1/*
2** 2001-09-15
3**
4** The author disclaims copyright to this source code. In place of
5** a legal notice, here is a blessing:
6**
7** May you do good and not evil.
8** May you find forgiveness for yourself and forgive others.
9** May you share freely, never taking more than you give.
10**
11*************************************************************************
12** This header file defines the interface that the SQLite library
13** presents to client programs. If a C-function, structure, datatype,
14** or constant definition does not appear in this file, then it is
15** not a published API of SQLite, is subject to change without
16** notice, and should not be referenced by programs that use SQLite.
17**
18** Some of the definitions that are in this file are marked as
19** "experimental". Experimental interfaces are normally new
20** features recently added to SQLite. We do not anticipate changes
21** to experimental interfaces but reserve the right to make minor changes
22** if experience from use "in the wild" suggest such changes are prudent.
23**
24** The official C-language API documentation for SQLite is derived
25** from comments in this file. This file is the authoritative source
26** on how SQLite interfaces are supposed to operate.
27**
28** The name of this file under configuration management is "sqlite.h.in".
29** The makefile makes some minor changes to this file (such as inserting
30** the version number) and changes its name to "sqlite3.h" as
31** part of the build process.
32*/
33#ifndef SQLITE3_H
34#define SQLITE3_H
35#include <stdarg.h> /* Needed for the definition of va_list */
36
37/*
38** Make sure we can call this stuff from C++.
39*/
40#ifdef __cplusplus
41extern "C" {
42#endif
43
44
45/*
46** Facilitate override of interface linkage and calling conventions.
47** Be aware that these macros may not be used within this particular
48** translation of the amalgamation and its associated header file.
49**
50** The SQLITE_EXTERN and SQLITE_API macros are used to instruct the
51** compiler that the target identifier should have external linkage.
52**
53** The SQLITE_CDECL macro is used to set the calling convention for
54** public functions that accept a variable number of arguments.
55**
56** The SQLITE_APICALL macro is used to set the calling convention for
57** public functions that accept a fixed number of arguments.
58**
59** The SQLITE_STDCALL macro is no longer used and is now deprecated.
60**
61** The SQLITE_CALLBACK macro is used to set the calling convention for
62** function pointers.
63**
64** The SQLITE_SYSAPI macro is used to set the calling convention for
65** functions provided by the operating system.
66**
67** Currently, the SQLITE_CDECL, SQLITE_APICALL, SQLITE_CALLBACK, and
68** SQLITE_SYSAPI macros are used only when building for environments
69** that require non-default calling conventions.
70*/
71#ifndef SQLITE_EXTERN
72# define SQLITE_EXTERN extern
73#endif
74#ifndef SQLITE_API
75# define SQLITE_API
76#endif
77#ifndef SQLITE_CDECL
78# define SQLITE_CDECL
79#endif
80#ifndef SQLITE_APICALL
81# define SQLITE_APICALL
82#endif
83#ifndef SQLITE_STDCALL
84# define SQLITE_STDCALL SQLITE_APICALL
85#endif
86#ifndef SQLITE_CALLBACK
87# define SQLITE_CALLBACK
88#endif
89#ifndef SQLITE_SYSAPI
90# define SQLITE_SYSAPI
91#endif
92
93/*
94** These no-op macros are used in front of interfaces to mark those
95** interfaces as either deprecated or experimental. New applications
96** should not use deprecated interfaces - they are supported for backwards
97** compatibility only. Application writers should be aware that
98** experimental interfaces are subject to change in point releases.
99**
100** These macros used to resolve to various kinds of compiler magic that
101** would generate warning messages when they were used. But that
102** compiler magic ended up generating such a flurry of bug reports
103** that we have taken it all out and gone back to using simple
104** noop macros.
105*/
106#define SQLITE_DEPRECATED
107#define SQLITE_EXPERIMENTAL
108
109/*
110** Ensure these symbols were not defined by some previous header file.
111*/
112#ifdef SQLITE_VERSION
113# undef SQLITE_VERSION
114#endif
115#ifdef SQLITE_VERSION_NUMBER
116# undef SQLITE_VERSION_NUMBER
117#endif
118
119/*
120** CAPI3REF: Compile-Time Library Version Numbers
121**
122** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
123** evaluates to a string literal that is the SQLite version in the
124** format "X.Y.Z" where X is the major version number (always 3 for
125** SQLite3) and Y is the minor version number and Z is the release number.)^
126** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
127** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
128** numbers used in [SQLITE_VERSION].)^
129** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
130** be larger than the release from which it is derived. Either Y will
131** be held constant and Z will be incremented or else Y will be incremented
132** and Z will be reset to zero.
133**
134** Since [version 3.6.18] ([dateof:3.6.18]),
135** SQLite source code has been stored in the
136** <a href="http://www.fossil-scm.org/">Fossil configuration management
137** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to
138** a string which identifies a particular check-in of SQLite
139** within its configuration management system. ^The SQLITE_SOURCE_ID
140** string contains the date and time of the check-in (UTC) and a SHA1
141** or SHA3-256 hash of the entire source tree. If the source code has
142** been edited in any way since it was last checked in, then the last
143** four hexadecimal digits of the hash may be modified.
144**
145** See also: [sqlite3_libversion()],
146** [sqlite3_libversion_number()], [sqlite3_sourceid()],
147** [sqlite_version()] and [sqlite_source_id()].
148*/
149#define SQLITE_VERSION "3.49.1"
150#define SQLITE_VERSION_NUMBER 3049001
151#define SQLITE_SOURCE_ID "2025-02-18 13:38:58 873d4e274b4988d260ba8354a9718324a1c26187a4ab4c1cc0227c03d0f10e70"
152
153/*
154** CAPI3REF: Run-Time Library Version Numbers
155** KEYWORDS: sqlite3_version sqlite3_sourceid
156**
157** These interfaces provide the same information as the [SQLITE_VERSION],
158** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
159** but are associated with the library instead of the header file. ^(Cautious
160** programmers might include assert() statements in their application to
161** verify that values returned by these interfaces match the macros in
162** the header, and thus ensure that the application is
163** compiled with matching library and header files.
164**
165** <blockquote><pre>
166** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
167** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
168** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
169** </pre></blockquote>)^
170**
171** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
172** macro. ^The sqlite3_libversion() function returns a pointer to the
173** to the sqlite3_version[] string constant. The sqlite3_libversion()
174** function is provided for use in DLLs since DLL users usually do not have
175** direct access to string constants within the DLL. ^The
176** sqlite3_libversion_number() function returns an integer equal to
177** [SQLITE_VERSION_NUMBER]. ^(The sqlite3_sourceid() function returns
178** a pointer to a string constant whose value is the same as the
179** [SQLITE_SOURCE_ID] C preprocessor macro. Except if SQLite is built
180** using an edited copy of [the amalgamation], then the last four characters
181** of the hash might be different from [SQLITE_SOURCE_ID].)^
182**
183** See also: [sqlite_version()] and [sqlite_source_id()].
184*/
185SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
186SQLITE_API const char *sqlite3_libversion(void);
187SQLITE_API const char *sqlite3_sourceid(void);
188SQLITE_API int sqlite3_libversion_number(void);
189
190/*
191** CAPI3REF: Run-Time Library Compilation Options Diagnostics
192**
193** ^The sqlite3_compileoption_used() function returns 0 or 1
194** indicating whether the specified option was defined at
195** compile time. ^The SQLITE_ prefix may be omitted from the
196** option name passed to sqlite3_compileoption_used().
197**
198** ^The sqlite3_compileoption_get() function allows iterating
199** over the list of options that were defined at compile time by
200** returning the N-th compile time option string. ^If N is out of range,
201** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_
202** prefix is omitted from any strings returned by
203** sqlite3_compileoption_get().
204**
205** ^Support for the diagnostic functions sqlite3_compileoption_used()
206** and sqlite3_compileoption_get() may be omitted by specifying the
207** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
208**
209** See also: SQL functions [sqlite_compileoption_used()] and
210** [sqlite_compileoption_get()] and the [compile_options pragma].
211*/
212#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
213SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
214SQLITE_API const char *sqlite3_compileoption_get(int N);
215#else
216# define sqlite3_compileoption_used(X) 0
217# define sqlite3_compileoption_get(X) ((void*)0)
218#endif
219
220/*
221** CAPI3REF: Test To See If The Library Is Threadsafe
222**
223** ^The sqlite3_threadsafe() function returns zero if and only if
224** SQLite was compiled with mutexing code omitted due to the
225** [SQLITE_THREADSAFE] compile-time option being set to 0.
226**
227** SQLite can be compiled with or without mutexes. When
228** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
229** are enabled and SQLite is threadsafe. When the
230** [SQLITE_THREADSAFE] macro is 0,
231** the mutexes are omitted. Without the mutexes, it is not safe
232** to use SQLite concurrently from more than one thread.
233**
234** Enabling mutexes incurs a measurable performance penalty.
235** So if speed is of utmost importance, it makes sense to disable
236** the mutexes. But for maximum safety, mutexes should be enabled.
237** ^The default behavior is for mutexes to be enabled.
238**
239** This interface can be used by an application to make sure that the
240** version of SQLite that it is linking against was compiled with
241** the desired setting of the [SQLITE_THREADSAFE] macro.
242**
243** This interface only reports on the compile-time mutex setting
244** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
245** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
246** can be fully or partially disabled using a call to [sqlite3_config()]
247** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
248** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the
249** sqlite3_threadsafe() function shows only the compile-time setting of
250** thread safety, not any run-time changes to that setting made by
251** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
252** is unchanged by calls to sqlite3_config().)^
253**
254** See the [threading mode] documentation for additional information.
255*/
256SQLITE_API int sqlite3_threadsafe(void);
257
258/*
259** CAPI3REF: Database Connection Handle
260** KEYWORDS: {database connection} {database connections}
261**
262** Each open SQLite database is represented by a pointer to an instance of
263** the opaque structure named "sqlite3". It is useful to think of an sqlite3
264** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
265** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
266** and [sqlite3_close_v2()] are its destructors. There are many other
267** interfaces (such as
268** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
269** [sqlite3_busy_timeout()] to name but three) that are methods on an
270** sqlite3 object.
271*/
272typedef struct sqlite3 sqlite3;
273
274/*
275** CAPI3REF: 64-Bit Integer Types
276** KEYWORDS: sqlite_int64 sqlite_uint64
277**
278** Because there is no cross-platform way to specify 64-bit integer types
279** SQLite includes typedefs for 64-bit signed and unsigned integers.
280**
281** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
282** The sqlite_int64 and sqlite_uint64 types are supported for backwards
283** compatibility only.
284**
285** ^The sqlite3_int64 and sqlite_int64 types can store integer values
286** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
287** sqlite3_uint64 and sqlite_uint64 types can store integer values
288** between 0 and +18446744073709551615 inclusive.
289*/
290#ifdef SQLITE_INT64_TYPE
291 typedef SQLITE_INT64_TYPE sqlite_int64;
292# ifdef SQLITE_UINT64_TYPE
293 typedef SQLITE_UINT64_TYPE sqlite_uint64;
294# else
295 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
296# endif
297#elif defined(_MSC_VER) || defined(__BORLANDC__)
298 typedef __int64 sqlite_int64;
299 typedef unsigned __int64 sqlite_uint64;
300#else
301 typedef long long int sqlite_int64;
302 typedef unsigned long long int sqlite_uint64;
303#endif
304typedef sqlite_int64 sqlite3_int64;
305typedef sqlite_uint64 sqlite3_uint64;
306
307/*
308** If compiling for a processor that lacks floating point support,
309** substitute integer for floating-point.
310*/
311#ifdef SQLITE_OMIT_FLOATING_POINT
312# define double sqlite3_int64
313#endif
314
315/*
316** CAPI3REF: Closing A Database Connection
317** DESTRUCTOR: sqlite3
318**
319** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
320** for the [sqlite3] object.
321** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
322** the [sqlite3] object is successfully destroyed and all associated
323** resources are deallocated.
324**
325** Ideally, applications should [sqlite3_finalize | finalize] all
326** [prepared statements], [sqlite3_blob_close | close] all [BLOB handles], and
327** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
328** with the [sqlite3] object prior to attempting to close the object.
329** ^If the database connection is associated with unfinalized prepared
330** statements, BLOB handlers, and/or unfinished sqlite3_backup objects then
331** sqlite3_close() will leave the database connection open and return
332** [SQLITE_BUSY]. ^If sqlite3_close_v2() is called with unfinalized prepared
333** statements, unclosed BLOB handlers, and/or unfinished sqlite3_backups,
334** it returns [SQLITE_OK] regardless, but instead of deallocating the database
335** connection immediately, it marks the database connection as an unusable
336** "zombie" and makes arrangements to automatically deallocate the database
337** connection after all prepared statements are finalized, all BLOB handles
338** are closed, and all backups have finished. The sqlite3_close_v2() interface
339** is intended for use with host languages that are garbage collected, and
340** where the order in which destructors are called is arbitrary.
341**
342** ^If an [sqlite3] object is destroyed while a transaction is open,
343** the transaction is automatically rolled back.
344**
345** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
346** must be either a NULL
347** pointer or an [sqlite3] object pointer obtained
348** from [sqlite3_open()], [sqlite3_open16()], or
349** [sqlite3_open_v2()], and not previously closed.
350** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
351** argument is a harmless no-op.
352*/
353SQLITE_API int sqlite3_close(sqlite3*);
354SQLITE_API int sqlite3_close_v2(sqlite3*);
355
356/*
357** The type for a callback function.
358** This is legacy and deprecated. It is included for historical
359** compatibility and is not documented.
360*/
361typedef int (*sqlite3_callback)(void*,int,char**, char**);
362
363/*
364** CAPI3REF: One-Step Query Execution Interface
365** METHOD: sqlite3
366**
367** The sqlite3_exec() interface is a convenience wrapper around
368** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
369** that allows an application to run multiple statements of SQL
370** without having to use a lot of C code.
371**
372** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
373** semicolon-separate SQL statements passed into its 2nd argument,
374** in the context of the [database connection] passed in as its 1st
375** argument. ^If the callback function of the 3rd argument to
376** sqlite3_exec() is not NULL, then it is invoked for each result row
377** coming out of the evaluated SQL statements. ^The 4th argument to
378** sqlite3_exec() is relayed through to the 1st argument of each
379** callback invocation. ^If the callback pointer to sqlite3_exec()
380** is NULL, then no callback is ever invoked and result rows are
381** ignored.
382**
383** ^If an error occurs while evaluating the SQL statements passed into
384** sqlite3_exec(), then execution of the current statement stops and
385** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
386** is not NULL then any error message is written into memory obtained
387** from [sqlite3_malloc()] and passed back through the 5th parameter.
388** To avoid memory leaks, the application should invoke [sqlite3_free()]
389** on error message strings returned through the 5th parameter of
390** sqlite3_exec() after the error message string is no longer needed.
391** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
392** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
393** NULL before returning.
394**
395** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
396** routine returns SQLITE_ABORT without invoking the callback again and
397** without running any subsequent SQL statements.
398**
399** ^The 2nd argument to the sqlite3_exec() callback function is the
400** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
401** callback is an array of pointers to strings obtained as if from
402** [sqlite3_column_text()], one for each column. ^If an element of a
403** result row is NULL then the corresponding string pointer for the
404** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
405** sqlite3_exec() callback is an array of pointers to strings where each
406** entry represents the name of corresponding result column as obtained
407** from [sqlite3_column_name()].
408**
409** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
410** to an empty string, or a pointer that contains only whitespace and/or
411** SQL comments, then no SQL statements are evaluated and the database
412** is not changed.
413**
414** Restrictions:
415**
416** <ul>
417** <li> The application must ensure that the 1st parameter to sqlite3_exec()
418** is a valid and open [database connection].
419** <li> The application must not close the [database connection] specified by
420** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
421** <li> The application must not modify the SQL statement text passed into
422** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
423** <li> The application must not dereference the arrays or string pointers
424** passed as the 3rd and 4th callback parameters after it returns.
425** </ul>
426*/
427SQLITE_API int sqlite3_exec(
428 sqlite3*, /* An open database */
429 const char *sql, /* SQL to be evaluated */
430 int (*callback)(void*,int,char**,char**), /* Callback function */
431 void *, /* 1st argument to callback */
432 char **errmsg /* Error msg written here */
433);
434
435/*
436** CAPI3REF: Result Codes
437** KEYWORDS: {result code definitions}
438**
439** Many SQLite functions return an integer result code from the set shown
440** here in order to indicate success or failure.
441**
442** New error codes may be added in future versions of SQLite.
443**
444** See also: [extended result code definitions]
445*/
446#define SQLITE_OK 0 /* Successful result */
447/* beginning-of-error-codes */
448#define SQLITE_ERROR 1 /* Generic error */
449#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
450#define SQLITE_PERM 3 /* Access permission denied */
451#define SQLITE_ABORT 4 /* Callback routine requested an abort */
452#define SQLITE_BUSY 5 /* The database file is locked */
453#define SQLITE_LOCKED 6 /* A table in the database is locked */
454#define SQLITE_NOMEM 7 /* A malloc() failed */
455#define SQLITE_READONLY 8 /* Attempt to write a readonly database */
456#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
457#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
458#define SQLITE_CORRUPT 11 /* The database disk image is malformed */
459#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
460#define SQLITE_FULL 13 /* Insertion failed because database is full */
461#define SQLITE_CANTOPEN 14 /* Unable to open the database file */
462#define SQLITE_PROTOCOL 15 /* Database lock protocol error */
463#define SQLITE_EMPTY 16 /* Internal use only */
464#define SQLITE_SCHEMA 17 /* The database schema changed */
465#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
466#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
467#define SQLITE_MISMATCH 20 /* Data type mismatch */
468#define SQLITE_MISUSE 21 /* Library used incorrectly */
469#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
470#define SQLITE_AUTH 23 /* Authorization denied */
471#define SQLITE_FORMAT 24 /* Not used */
472#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
473#define SQLITE_NOTADB 26 /* File opened that is not a database file */
474#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */
475#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */
476#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
477#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
478/* end-of-error-codes */
479
480/*
481** CAPI3REF: Extended Result Codes
482** KEYWORDS: {extended result code definitions}
483**
484** In its default configuration, SQLite API routines return one of 30 integer
485** [result codes]. However, experience has shown that many of
486** these result codes are too coarse-grained. They do not provide as
487** much information about problems as programmers might like. In an effort to
488** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8]
489** and later) include
490** support for additional result codes that provide more detailed information
491** about errors. These [extended result codes] are enabled or disabled
492** on a per database connection basis using the
493** [sqlite3_extended_result_codes()] API. Or, the extended code for
494** the most recent error can be obtained using
495** [sqlite3_extended_errcode()].
496*/
497#define SQLITE_ERROR_MISSING_COLLSEQ (SQLITE_ERROR | (1<<8))
498#define SQLITE_ERROR_RETRY (SQLITE_ERROR | (2<<8))
499#define SQLITE_ERROR_SNAPSHOT (SQLITE_ERROR | (3<<8))
500#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
501#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
502#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
503#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
504#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
505#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
506#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
507#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
508#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
509#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
510#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
511#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
512#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
513#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
514#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
515#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
516#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
517#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
518#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
519#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
520#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
521#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
522#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8))
523#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8))
524#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8))
525#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8))
526#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8))
527#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8))
528#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8))
529#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8))
530#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8))
531#define SQLITE_IOERR_DATA (SQLITE_IOERR | (32<<8))
532#define SQLITE_IOERR_CORRUPTFS (SQLITE_IOERR | (33<<8))
533#define SQLITE_IOERR_IN_PAGE (SQLITE_IOERR | (34<<8))
534#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
535#define SQLITE_LOCKED_VTAB (SQLITE_LOCKED | (2<<8))
536#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
537#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8))
538#define SQLITE_BUSY_TIMEOUT (SQLITE_BUSY | (3<<8))
539#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
540#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8))
541#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8))
542#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8))
543#define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) /* Not Used */
544#define SQLITE_CANTOPEN_SYMLINK (SQLITE_CANTOPEN | (6<<8))
545#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
546#define SQLITE_CORRUPT_SEQUENCE (SQLITE_CORRUPT | (2<<8))
547#define SQLITE_CORRUPT_INDEX (SQLITE_CORRUPT | (3<<8))
548#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
549#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
550#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8))
551#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8))
552#define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8))
553#define SQLITE_READONLY_DIRECTORY (SQLITE_READONLY | (6<<8))
554#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
555#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8))
556#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8))
557#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8))
558#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8))
559#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8))
560#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8))
561#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8))
562#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8))
563#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8))
564#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8))
565#define SQLITE_CONSTRAINT_PINNED (SQLITE_CONSTRAINT |(11<<8))
566#define SQLITE_CONSTRAINT_DATATYPE (SQLITE_CONSTRAINT |(12<<8))
567#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8))
568#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
569#define SQLITE_NOTICE_RBU (SQLITE_NOTICE | (3<<8))
570#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8))
571#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8))
572#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8))
573#define SQLITE_OK_SYMLINK (SQLITE_OK | (2<<8)) /* internal use only */
574
575/*
576** CAPI3REF: Flags For File Open Operations
577**
578** These bit values are intended for use in the
579** 3rd parameter to the [sqlite3_open_v2()] interface and
580** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
581**
582** Only those flags marked as "Ok for sqlite3_open_v2()" may be
583** used as the third argument to the [sqlite3_open_v2()] interface.
584** The other flags have historically been ignored by sqlite3_open_v2(),
585** though future versions of SQLite might change so that an error is
586** raised if any of the disallowed bits are passed into sqlite3_open_v2().
587** Applications should not depend on the historical behavior.
588**
589** Note in particular that passing the SQLITE_OPEN_EXCLUSIVE flag into
590** [sqlite3_open_v2()] does *not* cause the underlying database file
591** to be opened using O_EXCL. Passing SQLITE_OPEN_EXCLUSIVE into
592** [sqlite3_open_v2()] has historically be a no-op and might become an
593** error in future versions of SQLite.
594*/
595#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
596#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
597#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
598#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
599#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
600#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
601#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
602#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
603#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
604#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
605#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
606#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
607#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
608#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
609#define SQLITE_OPEN_SUPER_JOURNAL 0x00004000 /* VFS only */
610#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
611#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
612#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
613#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
614#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
615#define SQLITE_OPEN_NOFOLLOW 0x01000000 /* Ok for sqlite3_open_v2() */
616#define SQLITE_OPEN_EXRESCODE 0x02000000 /* Extended result codes */
617
618/* Reserved: 0x00F00000 */
619/* Legacy compatibility: */
620#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
621
622
623/*
624** CAPI3REF: Device Characteristics
625**
626** The xDeviceCharacteristics method of the [sqlite3_io_methods]
627** object returns an integer which is a vector of these
628** bit values expressing I/O characteristics of the mass storage
629** device that holds the file that the [sqlite3_io_methods]
630** refers to.
631**
632** The SQLITE_IOCAP_ATOMIC property means that all writes of
633** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
634** mean that writes of blocks that are nnn bytes in size and
635** are aligned to an address which is an integer multiple of
636** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
637** that when data is appended to a file, the data is appended
638** first then the size of the file is extended, never the other
639** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
640** information is written to disk in the same order as calls
641** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
642** after reboot following a crash or power loss, the only bytes in a
643** file that were written at the application level might have changed
644** and that adjacent bytes, even bytes within the same sector are
645** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
646** flag indicates that a file cannot be deleted when open. The
647** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
648** read-only media and cannot be changed even by processes with
649** elevated privileges.
650**
651** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
652** filesystem supports doing multiple write operations atomically when those
653** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
654** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].
655**
656** The SQLITE_IOCAP_SUBPAGE_READ property means that it is ok to read
657** from the database file in amounts that are not a multiple of the
658** page size and that do not begin at a page boundary. Without this
659** property, SQLite is careful to only do full-page reads and write
660** on aligned pages, with the one exception that it will do a sub-page
661** read of the first page to access the database header.
662*/
663#define SQLITE_IOCAP_ATOMIC 0x00000001
664#define SQLITE_IOCAP_ATOMIC512 0x00000002
665#define SQLITE_IOCAP_ATOMIC1K 0x00000004
666#define SQLITE_IOCAP_ATOMIC2K 0x00000008
667#define SQLITE_IOCAP_ATOMIC4K 0x00000010
668#define SQLITE_IOCAP_ATOMIC8K 0x00000020
669#define SQLITE_IOCAP_ATOMIC16K 0x00000040
670#define SQLITE_IOCAP_ATOMIC32K 0x00000080
671#define SQLITE_IOCAP_ATOMIC64K 0x00000100
672#define SQLITE_IOCAP_SAFE_APPEND 0x00000200
673#define SQLITE_IOCAP_SEQUENTIAL 0x00000400
674#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
675#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
676#define SQLITE_IOCAP_IMMUTABLE 0x00002000
677#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000
678#define SQLITE_IOCAP_SUBPAGE_READ 0x00008000
679
680/*
681** CAPI3REF: File Locking Levels
682**
683** SQLite uses one of these integer values as the second
684** argument to calls it makes to the xLock() and xUnlock() methods
685** of an [sqlite3_io_methods] object. These values are ordered from
686** lest restrictive to most restrictive.
687**
688** The argument to xLock() is always SHARED or higher. The argument to
689** xUnlock is either SHARED or NONE.
690*/
691#define SQLITE_LOCK_NONE 0 /* xUnlock() only */
692#define SQLITE_LOCK_SHARED 1 /* xLock() or xUnlock() */
693#define SQLITE_LOCK_RESERVED 2 /* xLock() only */
694#define SQLITE_LOCK_PENDING 3 /* xLock() only */
695#define SQLITE_LOCK_EXCLUSIVE 4 /* xLock() only */
696
697/*
698** CAPI3REF: Synchronization Type Flags
699**
700** When SQLite invokes the xSync() method of an
701** [sqlite3_io_methods] object it uses a combination of
702** these integer values as the second argument.
703**
704** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
705** sync operation only needs to flush data to mass storage. Inode
706** information need not be flushed. If the lower four bits of the flag
707** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
708** If the lower four bits equal SQLITE_SYNC_FULL, that means
709** to use Mac OS X style fullsync instead of fsync().
710**
711** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
712** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
713** settings. The [synchronous pragma] determines when calls to the
714** xSync VFS method occur and applies uniformly across all platforms.
715** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
716** energetic or rigorous or forceful the sync operations are and
717** only make a difference on Mac OSX for the default SQLite code.
718** (Third-party VFS implementations might also make the distinction
719** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
720** operating systems natively supported by SQLite, only Mac OSX
721** cares about the difference.)
722*/
723#define SQLITE_SYNC_NORMAL 0x00002
724#define SQLITE_SYNC_FULL 0x00003
725#define SQLITE_SYNC_DATAONLY 0x00010
726
727/*
728** CAPI3REF: OS Interface Open File Handle
729**
730** An [sqlite3_file] object represents an open file in the
731** [sqlite3_vfs | OS interface layer]. Individual OS interface
732** implementations will
733** want to subclass this object by appending additional fields
734** for their own use. The pMethods entry is a pointer to an
735** [sqlite3_io_methods] object that defines methods for performing
736** I/O operations on the open file.
737*/
738typedef struct sqlite3_file sqlite3_file;
739struct sqlite3_file {
740 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
741};
742
743/*
744** CAPI3REF: OS Interface File Virtual Methods Object
745**
746** Every file opened by the [sqlite3_vfs.xOpen] method populates an
747** [sqlite3_file] object (or, more commonly, a subclass of the
748** [sqlite3_file] object) with a pointer to an instance of this object.
749** This object defines the methods used to perform various operations
750** against the open file represented by the [sqlite3_file] object.
751**
752** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
753** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
754** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
755** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
756** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
757** to NULL.
758**
759** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
760** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
761** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
762** flag may be ORed in to indicate that only the data of the file
763** and not its inode needs to be synced.
764**
765** The integer values to xLock() and xUnlock() are one of
766** <ul>
767** <li> [SQLITE_LOCK_NONE],
768** <li> [SQLITE_LOCK_SHARED],
769** <li> [SQLITE_LOCK_RESERVED],
770** <li> [SQLITE_LOCK_PENDING], or
771** <li> [SQLITE_LOCK_EXCLUSIVE].
772** </ul>
773** xLock() upgrades the database file lock. In other words, xLock() moves the
774** database file lock in the direction NONE toward EXCLUSIVE. The argument to
775** xLock() is always one of SHARED, RESERVED, PENDING, or EXCLUSIVE, never
776** SQLITE_LOCK_NONE. If the database file lock is already at or above the
777** requested lock, then the call to xLock() is a no-op.
778** xUnlock() downgrades the database file lock to either SHARED or NONE.
779** If the lock is already at or below the requested lock state, then the call
780** to xUnlock() is a no-op.
781** The xCheckReservedLock() method checks whether any database connection,
782** either in this process or in some other process, is holding a RESERVED,
783** PENDING, or EXCLUSIVE lock on the file. It returns, via its output
784** pointer parameter, true if such a lock exists and false otherwise.
785**
786** The xFileControl() method is a generic interface that allows custom
787** VFS implementations to directly control an open file using the
788** [sqlite3_file_control()] interface. The second "op" argument is an
789** integer opcode. The third argument is a generic pointer intended to
790** point to a structure that may contain arguments or space in which to
791** write return values. Potential uses for xFileControl() might be
792** functions to enable blocking locks with timeouts, to change the
793** locking strategy (for example to use dot-file locks), to inquire
794** about the status of a lock, or to break stale locks. The SQLite
795** core reserves all opcodes less than 100 for its own use.
796** A [file control opcodes | list of opcodes] less than 100 is available.
797** Applications that define a custom xFileControl method should use opcodes
798** greater than 100 to avoid conflicts. VFS implementations should
799** return [SQLITE_NOTFOUND] for file control opcodes that they do not
800** recognize.
801**
802** The xSectorSize() method returns the sector size of the
803** device that underlies the file. The sector size is the
804** minimum write that can be performed without disturbing
805** other bytes in the file. The xDeviceCharacteristics()
806** method returns a bit vector describing behaviors of the
807** underlying device:
808**
809** <ul>
810** <li> [SQLITE_IOCAP_ATOMIC]
811** <li> [SQLITE_IOCAP_ATOMIC512]
812** <li> [SQLITE_IOCAP_ATOMIC1K]
813** <li> [SQLITE_IOCAP_ATOMIC2K]
814** <li> [SQLITE_IOCAP_ATOMIC4K]
815** <li> [SQLITE_IOCAP_ATOMIC8K]
816** <li> [SQLITE_IOCAP_ATOMIC16K]
817** <li> [SQLITE_IOCAP_ATOMIC32K]
818** <li> [SQLITE_IOCAP_ATOMIC64K]
819** <li> [SQLITE_IOCAP_SAFE_APPEND]
820** <li> [SQLITE_IOCAP_SEQUENTIAL]
821** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN]
822** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE]
823** <li> [SQLITE_IOCAP_IMMUTABLE]
824** <li> [SQLITE_IOCAP_BATCH_ATOMIC]
825** <li> [SQLITE_IOCAP_SUBPAGE_READ]
826** </ul>
827**
828** The SQLITE_IOCAP_ATOMIC property means that all writes of
829** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
830** mean that writes of blocks that are nnn bytes in size and
831** are aligned to an address which is an integer multiple of
832** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
833** that when data is appended to a file, the data is appended
834** first then the size of the file is extended, never the other
835** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
836** information is written to disk in the same order as calls
837** to xWrite().
838**
839** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
840** in the unread portions of the buffer with zeros. A VFS that
841** fails to zero-fill short reads might seem to work. However,
842** failure to zero-fill short reads will eventually lead to
843** database corruption.
844*/
845typedef struct sqlite3_io_methods sqlite3_io_methods;
846struct sqlite3_io_methods {
847 int iVersion;
848 int (*xClose)(sqlite3_file*);
849 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
850 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
851 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
852 int (*xSync)(sqlite3_file*, int flags);
853 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
854 int (*xLock)(sqlite3_file*, int);
855 int (*xUnlock)(sqlite3_file*, int);
856 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
857 int (*xFileControl)(sqlite3_file*, int op, void *pArg);
858 int (*xSectorSize)(sqlite3_file*);
859 int (*xDeviceCharacteristics)(sqlite3_file*);
860 /* Methods above are valid for version 1 */
861 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
862 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
863 void (*xShmBarrier)(sqlite3_file*);
864 int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
865 /* Methods above are valid for version 2 */
866 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
867 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
868 /* Methods above are valid for version 3 */
869 /* Additional methods may be added in future releases */
870};
871
872/*
873** CAPI3REF: Standard File Control Opcodes
874** KEYWORDS: {file control opcodes} {file control opcode}
875**
876** These integer constants are opcodes for the xFileControl method
877** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
878** interface.
879**
880** <ul>
881** <li>[[SQLITE_FCNTL_LOCKSTATE]]
882** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
883** opcode causes the xFileControl method to write the current state of
884** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
885** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
886** into an integer that the pArg argument points to.
887** This capability is only available if SQLite is compiled with [SQLITE_DEBUG].
888**
889** <li>[[SQLITE_FCNTL_SIZE_HINT]]
890** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
891** layer a hint of how large the database file will grow to be during the
892** current transaction. This hint is not guaranteed to be accurate but it
893** is often close. The underlying VFS might choose to preallocate database
894** file space based on this hint in order to help writes to the database
895** file run faster.
896**
897** <li>[[SQLITE_FCNTL_SIZE_LIMIT]]
898** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that
899** implements [sqlite3_deserialize()] to set an upper bound on the size
900** of the in-memory database. The argument is a pointer to a [sqlite3_int64].
901** If the integer pointed to is negative, then it is filled in with the
902** current limit. Otherwise the limit is set to the larger of the value
903** of the integer pointed to and the current database size. The integer
904** pointed to is set to the new limit.
905**
906** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
907** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
908** extends and truncates the database file in chunks of a size specified
909** by the user. The fourth argument to [sqlite3_file_control()] should
910** point to an integer (type int) containing the new chunk-size to use
911** for the nominated database. Allocating database file space in large
912** chunks (say 1MB at a time), may reduce file-system fragmentation and
913** improve performance on some systems.
914**
915** <li>[[SQLITE_FCNTL_FILE_POINTER]]
916** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
917** to the [sqlite3_file] object associated with a particular database
918** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER].
919**
920** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
921** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
922** to the [sqlite3_file] object associated with the journal file (either
923** the [rollback journal] or the [write-ahead log]) for a particular database
924** connection. See also [SQLITE_FCNTL_FILE_POINTER].
925**
926** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
927** No longer in use.
928**
929** <li>[[SQLITE_FCNTL_SYNC]]
930** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
931** sent to the VFS immediately before the xSync method is invoked on a
932** database file descriptor. Or, if the xSync method is not invoked
933** because the user has configured SQLite with
934** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
935** of the xSync method. In most cases, the pointer argument passed with
936** this file-control is NULL. However, if the database file is being synced
937** as part of a multi-database commit, the argument points to a nul-terminated
938** string containing the transactions super-journal file name. VFSes that
939** do not need this signal should silently ignore this opcode. Applications
940** should not call [sqlite3_file_control()] with this opcode as doing so may
941** disrupt the operation of the specialized VFSes that do require it.
942**
943** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
944** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
945** and sent to the VFS after a transaction has been committed immediately
946** but before the database is unlocked. VFSes that do not need this signal
947** should silently ignore this opcode. Applications should not call
948** [sqlite3_file_control()] with this opcode as doing so may disrupt the
949** operation of the specialized VFSes that do require it.
950**
951** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
952** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
953** retry counts and intervals for certain disk I/O operations for the
954** windows [VFS] in order to provide robustness in the presence of
955** anti-virus programs. By default, the windows VFS will retry file read,
956** file write, and file delete operations up to 10 times, with a delay
957** of 25 milliseconds before the first retry and with the delay increasing
958** by an additional 25 milliseconds with each subsequent retry. This
959** opcode allows these two values (10 retries and 25 milliseconds of delay)
960** to be adjusted. The values are changed for all database connections
961** within the same process. The argument is a pointer to an array of two
962** integers where the first integer is the new retry count and the second
963** integer is the delay. If either integer is negative, then the setting
964** is not changed but instead the prior value of that setting is written
965** into the array entry, allowing the current retry settings to be
966** interrogated. The zDbName parameter is ignored.
967**
968** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
969** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
970** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary
971** write ahead log ([WAL file]) and shared memory
972** files used for transaction control
973** are automatically deleted when the latest connection to the database
974** closes. Setting persistent WAL mode causes those files to persist after
975** close. Persisting the files is useful when other processes that do not
976** have write permission on the directory containing the database file want
977** to read the database file, as the WAL and shared memory files must exist
978** in order for the database to be readable. The fourth parameter to
979** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
980** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
981** WAL mode. If the integer is -1, then it is overwritten with the current
982** WAL persistence setting.
983**
984** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
985** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
986** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
987** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
988** xDeviceCharacteristics methods. The fourth parameter to
989** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
990** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
991** mode. If the integer is -1, then it is overwritten with the current
992** zero-damage mode setting.
993**
994** <li>[[SQLITE_FCNTL_OVERWRITE]]
995** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
996** a write transaction to indicate that, unless it is rolled back for some
997** reason, the entire database file will be overwritten by the current
998** transaction. This is used by VACUUM operations.
999**
1000** <li>[[SQLITE_FCNTL_VFSNAME]]
1001** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
1002** all [VFSes] in the VFS stack. The names are of all VFS shims and the
1003** final bottom-level VFS are written into memory obtained from
1004** [sqlite3_malloc()] and the result is stored in the char* variable
1005** that the fourth parameter of [sqlite3_file_control()] points to.
1006** The caller is responsible for freeing the memory when done. As with
1007** all file-control actions, there is no guarantee that this will actually
1008** do anything. Callers should initialize the char* variable to a NULL
1009** pointer in case this file-control is not implemented. This file-control
1010** is intended for diagnostic use only.
1011**
1012** <li>[[SQLITE_FCNTL_VFS_POINTER]]
1013** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
1014** [VFSes] currently in use. ^(The argument X in
1015** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
1016** of type "[sqlite3_vfs] **". This opcodes will set *X
1017** to a pointer to the top-level VFS.)^
1018** ^When there are multiple VFS shims in the stack, this opcode finds the
1019** upper-most shim only.
1020**
1021** <li>[[SQLITE_FCNTL_PRAGMA]]
1022** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
1023** file control is sent to the open [sqlite3_file] object corresponding
1024** to the database file to which the pragma statement refers. ^The argument
1025** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
1026** pointers to strings (char**) in which the second element of the array
1027** is the name of the pragma and the third element is the argument to the
1028** pragma or NULL if the pragma has no argument. ^The handler for an
1029** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
1030** of the char** argument point to a string obtained from [sqlite3_mprintf()]
1031** or the equivalent and that string will become the result of the pragma or
1032** the error message if the pragma fails. ^If the
1033** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
1034** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
1035** file control returns [SQLITE_OK], then the parser assumes that the
1036** VFS has handled the PRAGMA itself and the parser generates a no-op
1037** prepared statement if result string is NULL, or that returns a copy
1038** of the result string if the string is non-NULL.
1039** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
1040** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
1041** that the VFS encountered an error while handling the [PRAGMA] and the
1042** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
1043** file control occurs at the beginning of pragma statement analysis and so
1044** it is able to override built-in [PRAGMA] statements.
1045**
1046** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
1047** ^The [SQLITE_FCNTL_BUSYHANDLER]
1048** file-control may be invoked by SQLite on the database file handle
1049** shortly after it is opened in order to provide a custom VFS with access
1050** to the connection's busy-handler callback. The argument is of type (void**)
1051** - an array of two (void *) values. The first (void *) actually points
1052** to a function of type (int (*)(void *)). In order to invoke the connection's
1053** busy-handler, this function should be invoked with the second (void *) in
1054** the array as the only argument. If it returns non-zero, then the operation
1055** should be retried. If it returns zero, the custom VFS should abandon the
1056** current operation.
1057**
1058** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
1059** ^Applications can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
1060** to have SQLite generate a
1061** temporary filename using the same algorithm that is followed to generate
1062** temporary filenames for TEMP tables and other internal uses. The
1063** argument should be a char** which will be filled with the filename
1064** written into memory obtained from [sqlite3_malloc()]. The caller should
1065** invoke [sqlite3_free()] on the result to avoid a memory leak.
1066**
1067** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
1068** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
1069** maximum number of bytes that will be used for memory-mapped I/O.
1070** The argument is a pointer to a value of type sqlite3_int64 that
1071** is an advisory maximum number of bytes in the file to memory map. The
1072** pointer is overwritten with the old value. The limit is not changed if
1073** the value originally pointed to is negative, and so the current limit
1074** can be queried by passing in a pointer to a negative number. This
1075** file-control is used internally to implement [PRAGMA mmap_size].
1076**
1077** <li>[[SQLITE_FCNTL_TRACE]]
1078** The [SQLITE_FCNTL_TRACE] file control provides advisory information
1079** to the VFS about what the higher layers of the SQLite stack are doing.
1080** This file control is used by some VFS activity tracing [shims].
1081** The argument is a zero-terminated string. Higher layers in the
1082** SQLite stack may generate instances of this file control if
1083** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
1084**
1085** <li>[[SQLITE_FCNTL_HAS_MOVED]]
1086** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
1087** pointer to an integer and it writes a boolean into that integer depending
1088** on whether or not the file has been renamed, moved, or deleted since it
1089** was first opened.
1090**
1091** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]]
1092** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
1093** underlying native file handle associated with a file handle. This file
1094** control interprets its argument as a pointer to a native file handle and
1095** writes the resulting value there.
1096**
1097** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
1098** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This
1099** opcode causes the xFileControl method to swap the file handle with the one
1100** pointed to by the pArg argument. This capability is used during testing
1101** and only needs to be supported when SQLITE_TEST is defined.
1102**
1103** <li>[[SQLITE_FCNTL_NULL_IO]]
1104** The [SQLITE_FCNTL_NULL_IO] opcode sets the low-level file descriptor
1105** or file handle for the [sqlite3_file] object such that it will no longer
1106** read or write to the database file.
1107**
1108** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
1109** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
1110** be advantageous to block on the next WAL lock if the lock is not immediately
1111** available. The WAL subsystem issues this signal during rare
1112** circumstances in order to fix a problem with priority inversion.
1113** Applications should <em>not</em> use this file-control.
1114**
1115** <li>[[SQLITE_FCNTL_ZIPVFS]]
1116** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
1117** VFS should return SQLITE_NOTFOUND for this opcode.
1118**
1119** <li>[[SQLITE_FCNTL_RBU]]
1120** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
1121** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for
1122** this opcode.
1123**
1124** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]]
1125** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
1126** the file descriptor is placed in "batch write mode", which
1127** means all subsequent write operations will be deferred and done
1128** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems
1129** that do not support batch atomic writes will return SQLITE_NOTFOUND.
1130** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
1131** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
1132** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make
1133** no VFS interface calls on the same [sqlite3_file] file descriptor
1134** except for calls to the xWrite method and the xFileControl method
1135** with [SQLITE_FCNTL_SIZE_HINT].
1136**
1137** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]]
1138** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
1139** operations since the previous successful call to
1140** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
1141** This file control returns [SQLITE_OK] if and only if the writes were
1142** all performed successfully and have been committed to persistent storage.
1143** ^Regardless of whether or not it is successful, this file control takes
1144** the file descriptor out of batch write mode so that all subsequent
1145** write operations are independent.
1146** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
1147** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1148**
1149** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]]
1150** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
1151** operations since the previous successful call to
1152** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
1153** ^This file control takes the file descriptor out of batch write mode
1154** so that all subsequent write operations are independent.
1155** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
1156** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1157**
1158** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]]
1159** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS
1160** to block for up to M milliseconds before failing when attempting to
1161** obtain a file lock using the xLock or xShmLock methods of the VFS.
1162** The parameter is a pointer to a 32-bit signed integer that contains
1163** the value that M is to be set to. Before returning, the 32-bit signed
1164** integer is overwritten with the previous value of M.
1165**
1166** <li>[[SQLITE_FCNTL_DATA_VERSION]]
1167** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to
1168** a database file. The argument is a pointer to a 32-bit unsigned integer.
1169** The "data version" for the pager is written into the pointer. The
1170** "data version" changes whenever any change occurs to the corresponding
1171** database file, either through SQL statements on the same database
1172** connection or through transactions committed by separate database
1173** connections possibly in other processes. The [sqlite3_total_changes()]
1174** interface can be used to find if any database on the connection has changed,
1175** but that interface responds to changes on TEMP as well as MAIN and does
1176** not provide a mechanism to detect changes to MAIN only. Also, the
1177** [sqlite3_total_changes()] interface responds to internal changes only and
1178** omits changes made by other database connections. The
1179** [PRAGMA data_version] command provides a mechanism to detect changes to
1180** a single attached database that occur due to other database connections,
1181** but omits changes implemented by the database connection on which it is
1182** called. This file control is the only mechanism to detect changes that
1183** happen either internally or externally and that are associated with
1184** a particular attached database.
1185**
1186** <li>[[SQLITE_FCNTL_CKPT_START]]
1187** The [SQLITE_FCNTL_CKPT_START] opcode is invoked from within a checkpoint
1188** in wal mode before the client starts to copy pages from the wal
1189** file to the database file.
1190**
1191** <li>[[SQLITE_FCNTL_CKPT_DONE]]
1192** The [SQLITE_FCNTL_CKPT_DONE] opcode is invoked from within a checkpoint
1193** in wal mode after the client has finished copying pages from the wal
1194** file to the database file, but before the *-shm file is updated to
1195** record the fact that the pages have been checkpointed.
1196**
1197** <li>[[SQLITE_FCNTL_EXTERNAL_READER]]
1198** The EXPERIMENTAL [SQLITE_FCNTL_EXTERNAL_READER] opcode is used to detect
1199** whether or not there is a database client in another process with a wal-mode
1200** transaction open on the database or not. It is only available on unix.The
1201** (void*) argument passed with this file-control should be a pointer to a
1202** value of type (int). The integer value is set to 1 if the database is a wal
1203** mode database and there exists at least one client in another process that
1204** currently has an SQL transaction open on the database. It is set to 0 if
1205** the database is not a wal-mode db, or if there is no such connection in any
1206** other process. This opcode cannot be used to detect transactions opened
1207** by clients within the current process, only within other processes.
1208**
1209** <li>[[SQLITE_FCNTL_CKSM_FILE]]
1210** The [SQLITE_FCNTL_CKSM_FILE] opcode is for use internally by the
1211** [checksum VFS shim] only.
1212**
1213** <li>[[SQLITE_FCNTL_RESET_CACHE]]
1214** If there is currently no transaction open on the database, and the
1215** database is not a temp db, then the [SQLITE_FCNTL_RESET_CACHE] file-control
1216** purges the contents of the in-memory page cache. If there is an open
1217** transaction, or if the db is a temp-db, this opcode is a no-op, not an error.
1218** </ul>
1219*/
1220#define SQLITE_FCNTL_LOCKSTATE 1
1221#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2
1222#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3
1223#define SQLITE_FCNTL_LAST_ERRNO 4
1224#define SQLITE_FCNTL_SIZE_HINT 5
1225#define SQLITE_FCNTL_CHUNK_SIZE 6
1226#define SQLITE_FCNTL_FILE_POINTER 7
1227#define SQLITE_FCNTL_SYNC_OMITTED 8
1228#define SQLITE_FCNTL_WIN32_AV_RETRY 9
1229#define SQLITE_FCNTL_PERSIST_WAL 10
1230#define SQLITE_FCNTL_OVERWRITE 11
1231#define SQLITE_FCNTL_VFSNAME 12
1232#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
1233#define SQLITE_FCNTL_PRAGMA 14
1234#define SQLITE_FCNTL_BUSYHANDLER 15
1235#define SQLITE_FCNTL_TEMPFILENAME 16
1236#define SQLITE_FCNTL_MMAP_SIZE 18
1237#define SQLITE_FCNTL_TRACE 19
1238#define SQLITE_FCNTL_HAS_MOVED 20
1239#define SQLITE_FCNTL_SYNC 21
1240#define SQLITE_FCNTL_COMMIT_PHASETWO 22
1241#define SQLITE_FCNTL_WIN32_SET_HANDLE 23
1242#define SQLITE_FCNTL_WAL_BLOCK 24
1243#define SQLITE_FCNTL_ZIPVFS 25
1244#define SQLITE_FCNTL_RBU 26
1245#define SQLITE_FCNTL_VFS_POINTER 27
1246#define SQLITE_FCNTL_JOURNAL_POINTER 28
1247#define SQLITE_FCNTL_WIN32_GET_HANDLE 29
1248#define SQLITE_FCNTL_PDB 30
1249#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31
1250#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32
1251#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33
1252#define SQLITE_FCNTL_LOCK_TIMEOUT 34
1253#define SQLITE_FCNTL_DATA_VERSION 35
1254#define SQLITE_FCNTL_SIZE_LIMIT 36
1255#define SQLITE_FCNTL_CKPT_DONE 37
1256#define SQLITE_FCNTL_RESERVE_BYTES 38
1257#define SQLITE_FCNTL_CKPT_START 39
1258#define SQLITE_FCNTL_EXTERNAL_READER 40
1259#define SQLITE_FCNTL_CKSM_FILE 41
1260#define SQLITE_FCNTL_RESET_CACHE 42
1261#define SQLITE_FCNTL_NULL_IO 43
1262
1263/* deprecated names */
1264#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE
1265#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE
1266#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO
1267
1268
1269/*
1270** CAPI3REF: Mutex Handle
1271**
1272** The mutex module within SQLite defines [sqlite3_mutex] to be an
1273** abstract type for a mutex object. The SQLite core never looks
1274** at the internal representation of an [sqlite3_mutex]. It only
1275** deals with pointers to the [sqlite3_mutex] object.
1276**
1277** Mutexes are created using [sqlite3_mutex_alloc()].
1278*/
1279typedef struct sqlite3_mutex sqlite3_mutex;
1280
1281/*
1282** CAPI3REF: Loadable Extension Thunk
1283**
1284** A pointer to the opaque sqlite3_api_routines structure is passed as
1285** the third parameter to entry points of [loadable extensions]. This
1286** structure must be typedefed in order to work around compiler warnings
1287** on some platforms.
1288*/
1289typedef struct sqlite3_api_routines sqlite3_api_routines;
1290
1291/*
1292** CAPI3REF: File Name
1293**
1294** Type [sqlite3_filename] is used by SQLite to pass filenames to the
1295** xOpen method of a [VFS]. It may be cast to (const char*) and treated
1296** as a normal, nul-terminated, UTF-8 buffer containing the filename, but
1297** may also be passed to special APIs such as:
1298**
1299** <ul>
1300** <li> sqlite3_filename_database()
1301** <li> sqlite3_filename_journal()
1302** <li> sqlite3_filename_wal()
1303** <li> sqlite3_uri_parameter()
1304** <li> sqlite3_uri_boolean()
1305** <li> sqlite3_uri_int64()
1306** <li> sqlite3_uri_key()
1307** </ul>
1308*/
1309typedef const char *sqlite3_filename;
1310
1311/*
1312** CAPI3REF: OS Interface Object
1313**
1314** An instance of the sqlite3_vfs object defines the interface between
1315** the SQLite core and the underlying operating system. The "vfs"
1316** in the name of the object stands for "virtual file system". See
1317** the [VFS | VFS documentation] for further information.
1318**
1319** The VFS interface is sometimes extended by adding new methods onto
1320** the end. Each time such an extension occurs, the iVersion field
1321** is incremented. The iVersion value started out as 1 in
1322** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
1323** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
1324** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields
1325** may be appended to the sqlite3_vfs object and the iVersion value
1326** may increase again in future versions of SQLite.
1327** Note that due to an oversight, the structure
1328** of the sqlite3_vfs object changed in the transition from
1329** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
1330** and yet the iVersion field was not increased.
1331**
1332** The szOsFile field is the size of the subclassed [sqlite3_file]
1333** structure used by this VFS. mxPathname is the maximum length of
1334** a pathname in this VFS.
1335**
1336** Registered sqlite3_vfs objects are kept on a linked list formed by
1337** the pNext pointer. The [sqlite3_vfs_register()]
1338** and [sqlite3_vfs_unregister()] interfaces manage this list
1339** in a thread-safe way. The [sqlite3_vfs_find()] interface
1340** searches the list. Neither the application code nor the VFS
1341** implementation should use the pNext pointer.
1342**
1343** The pNext field is the only field in the sqlite3_vfs
1344** structure that SQLite will ever modify. SQLite will only access
1345** or modify this field while holding a particular static mutex.
1346** The application should never modify anything within the sqlite3_vfs
1347** object once the object has been registered.
1348**
1349** The zName field holds the name of the VFS module. The name must
1350** be unique across all VFS modules.
1351**
1352** [[sqlite3_vfs.xOpen]]
1353** ^SQLite guarantees that the zFilename parameter to xOpen
1354** is either a NULL pointer or string obtained
1355** from xFullPathname() with an optional suffix added.
1356** ^If a suffix is added to the zFilename parameter, it will
1357** consist of a single "-" character followed by no more than
1358** 11 alphanumeric and/or "-" characters.
1359** ^SQLite further guarantees that
1360** the string will be valid and unchanged until xClose() is
1361** called. Because of the previous sentence,
1362** the [sqlite3_file] can safely store a pointer to the
1363** filename if it needs to remember the filename for some reason.
1364** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1365** must invent its own temporary name for the file. ^Whenever the
1366** xFilename parameter is NULL it will also be the case that the
1367** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1368**
1369** The flags argument to xOpen() includes all bits set in
1370** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
1371** or [sqlite3_open16()] is used, then flags includes at least
1372** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1373** If xOpen() opens a file read-only then it sets *pOutFlags to
1374** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
1375**
1376** ^(SQLite will also add one of the following flags to the xOpen()
1377** call, depending on the object being opened:
1378**
1379** <ul>
1380** <li> [SQLITE_OPEN_MAIN_DB]
1381** <li> [SQLITE_OPEN_MAIN_JOURNAL]
1382** <li> [SQLITE_OPEN_TEMP_DB]
1383** <li> [SQLITE_OPEN_TEMP_JOURNAL]
1384** <li> [SQLITE_OPEN_TRANSIENT_DB]
1385** <li> [SQLITE_OPEN_SUBJOURNAL]
1386** <li> [SQLITE_OPEN_SUPER_JOURNAL]
1387** <li> [SQLITE_OPEN_WAL]
1388** </ul>)^
1389**
1390** The file I/O implementation can use the object type flags to
1391** change the way it deals with files. For example, an application
1392** that does not care about crash recovery or rollback might make
1393** the open of a journal file a no-op. Writes to this journal would
1394** also be no-ops, and any attempt to read the journal would return
1395** SQLITE_IOERR. Or the implementation might recognize that a database
1396** file will be doing page-aligned sector reads and writes in a random
1397** order and set up its I/O subsystem accordingly.
1398**
1399** SQLite might also add one of the following flags to the xOpen method:
1400**
1401** <ul>
1402** <li> [SQLITE_OPEN_DELETEONCLOSE]
1403** <li> [SQLITE_OPEN_EXCLUSIVE]
1404** </ul>
1405**
1406** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1407** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
1408** will be set for TEMP databases and their journals, transient
1409** databases, and subjournals.
1410**
1411** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1412** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1413** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1414** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1415** SQLITE_OPEN_CREATE, is used to indicate that file should always
1416** be created, and that it is an error if it already exists.
1417** It is <i>not</i> used to indicate the file should be opened
1418** for exclusive access.
1419**
1420** ^At least szOsFile bytes of memory are allocated by SQLite
1421** to hold the [sqlite3_file] structure passed as the third
1422** argument to xOpen. The xOpen method does not have to
1423** allocate the structure; it should just fill it in. Note that
1424** the xOpen method must set the sqlite3_file.pMethods to either
1425** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
1426** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
1427** element will be valid after xOpen returns regardless of the success
1428** or failure of the xOpen call.
1429**
1430** [[sqlite3_vfs.xAccess]]
1431** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1432** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1433** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1434** to test whether a file is at least readable. The SQLITE_ACCESS_READ
1435** flag is never actually used and is not implemented in the built-in
1436** VFSes of SQLite. The file is named by the second argument and can be a
1437** directory. The xAccess method returns [SQLITE_OK] on success or some
1438** non-zero error code if there is an I/O error or if the name of
1439** the file given in the second argument is illegal. If SQLITE_OK
1440** is returned, then non-zero or zero is written into *pResOut to indicate
1441** whether or not the file is accessible.
1442**
1443** ^SQLite will always allocate at least mxPathname+1 bytes for the
1444** output buffer xFullPathname. The exact size of the output buffer
1445** is also passed as a parameter to both methods. If the output buffer
1446** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1447** handled as a fatal error by SQLite, vfs implementations should endeavor
1448** to prevent this by setting mxPathname to a sufficiently large value.
1449**
1450** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1451** interfaces are not strictly a part of the filesystem, but they are
1452** included in the VFS structure for completeness.
1453** The xRandomness() function attempts to return nBytes bytes
1454** of good-quality randomness into zOut. The return value is
1455** the actual number of bytes of randomness obtained.
1456** The xSleep() method causes the calling thread to sleep for at
1457** least the number of microseconds given. ^The xCurrentTime()
1458** method returns a Julian Day Number for the current date and time as
1459** a floating point value.
1460** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1461** Day Number multiplied by 86400000 (the number of milliseconds in
1462** a 24-hour day).
1463** ^SQLite will use the xCurrentTimeInt64() method to get the current
1464** date and time if that method is available (if iVersion is 2 or
1465** greater and the function pointer is not NULL) and will fall back
1466** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1467**
1468** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1469** are not used by the SQLite core. These optional interfaces are provided
1470** by some VFSes to facilitate testing of the VFS code. By overriding
1471** system calls with functions under its control, a test program can
1472** simulate faults and error conditions that would otherwise be difficult
1473** or impossible to induce. The set of system calls that can be overridden
1474** varies from one VFS to another, and from one version of the same VFS to the
1475** next. Applications that use these interfaces must be prepared for any
1476** or all of these interfaces to be NULL or for their behavior to change
1477** from one release to the next. Applications must not attempt to access
1478** any of these methods if the iVersion of the VFS is less than 3.
1479*/
1480typedef struct sqlite3_vfs sqlite3_vfs;
1481typedef void (*sqlite3_syscall_ptr)(void);
1482struct sqlite3_vfs {
1483 int iVersion; /* Structure version number (currently 3) */
1484 int szOsFile; /* Size of subclassed sqlite3_file */
1485 int mxPathname; /* Maximum file pathname length */
1486 sqlite3_vfs *pNext; /* Next registered VFS */
1487 const char *zName; /* Name of this virtual file system */
1488 void *pAppData; /* Pointer to application-specific data */
1489 int (*xOpen)(sqlite3_vfs*, sqlite3_filename zName, sqlite3_file*,
1490 int flags, int *pOutFlags);
1491 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1492 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1493 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1494 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1495 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1496 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1497 void (*xDlClose)(sqlite3_vfs*, void*);
1498 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1499 int (*xSleep)(sqlite3_vfs*, int microseconds);
1500 int (*xCurrentTime)(sqlite3_vfs*, double*);
1501 int (*xGetLastError)(sqlite3_vfs*, int, char *);
1502 /*
1503 ** The methods above are in version 1 of the sqlite_vfs object
1504 ** definition. Those that follow are added in version 2 or later
1505 */
1506 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1507 /*
1508 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1509 ** Those below are for version 3 and greater.
1510 */
1511 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1512 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1513 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1514 /*
1515 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1516 ** New fields may be appended in future versions. The iVersion
1517 ** value will increment whenever this happens.
1518 */
1519};
1520
1521/*
1522** CAPI3REF: Flags for the xAccess VFS method
1523**
1524** These integer constants can be used as the third parameter to
1525** the xAccess method of an [sqlite3_vfs] object. They determine
1526** what kind of permissions the xAccess method is looking for.
1527** With SQLITE_ACCESS_EXISTS, the xAccess method
1528** simply checks whether the file exists.
1529** With SQLITE_ACCESS_READWRITE, the xAccess method
1530** checks whether the named directory is both readable and writable
1531** (in other words, if files can be added, removed, and renamed within
1532** the directory).
1533** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1534** [temp_store_directory pragma], though this could change in a future
1535** release of SQLite.
1536** With SQLITE_ACCESS_READ, the xAccess method
1537** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
1538** currently unused, though it might be used in a future release of
1539** SQLite.
1540*/
1541#define SQLITE_ACCESS_EXISTS 0
1542#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
1543#define SQLITE_ACCESS_READ 2 /* Unused */
1544
1545/*
1546** CAPI3REF: Flags for the xShmLock VFS method
1547**
1548** These integer constants define the various locking operations
1549** allowed by the xShmLock method of [sqlite3_io_methods]. The
1550** following are the only legal combinations of flags to the
1551** xShmLock method:
1552**
1553** <ul>
1554** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1555** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1556** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1557** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1558** </ul>
1559**
1560** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1561** was given on the corresponding lock.
1562**
1563** The xShmLock method can transition between unlocked and SHARED or
1564** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1565** and EXCLUSIVE.
1566*/
1567#define SQLITE_SHM_UNLOCK 1
1568#define SQLITE_SHM_LOCK 2
1569#define SQLITE_SHM_SHARED 4
1570#define SQLITE_SHM_EXCLUSIVE 8
1571
1572/*
1573** CAPI3REF: Maximum xShmLock index
1574**
1575** The xShmLock method on [sqlite3_io_methods] may use values
1576** between 0 and this upper bound as its "offset" argument.
1577** The SQLite core will never attempt to acquire or release a
1578** lock outside of this range
1579*/
1580#define SQLITE_SHM_NLOCK 8
1581
1582
1583/*
1584** CAPI3REF: Initialize The SQLite Library
1585**
1586** ^The sqlite3_initialize() routine initializes the
1587** SQLite library. ^The sqlite3_shutdown() routine
1588** deallocates any resources that were allocated by sqlite3_initialize().
1589** These routines are designed to aid in process initialization and
1590** shutdown on embedded systems. Workstation applications using
1591** SQLite normally do not need to invoke either of these routines.
1592**
1593** A call to sqlite3_initialize() is an "effective" call if it is
1594** the first time sqlite3_initialize() is invoked during the lifetime of
1595** the process, or if it is the first time sqlite3_initialize() is invoked
1596** following a call to sqlite3_shutdown(). ^(Only an effective call
1597** of sqlite3_initialize() does any initialization. All other calls
1598** are harmless no-ops.)^
1599**
1600** A call to sqlite3_shutdown() is an "effective" call if it is the first
1601** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1602** an effective call to sqlite3_shutdown() does any deinitialization.
1603** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1604**
1605** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1606** is not. The sqlite3_shutdown() interface must only be called from a
1607** single thread. All open [database connections] must be closed and all
1608** other SQLite resources must be deallocated prior to invoking
1609** sqlite3_shutdown().
1610**
1611** Among other things, ^sqlite3_initialize() will invoke
1612** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1613** will invoke sqlite3_os_end().
1614**
1615** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1616** ^If for some reason, sqlite3_initialize() is unable to initialize
1617** the library (perhaps it is unable to allocate a needed resource such
1618** as a mutex) it returns an [error code] other than [SQLITE_OK].
1619**
1620** ^The sqlite3_initialize() routine is called internally by many other
1621** SQLite interfaces so that an application usually does not need to
1622** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1623** calls sqlite3_initialize() so the SQLite library will be automatically
1624** initialized when [sqlite3_open()] is called if it has not be initialized
1625** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1626** compile-time option, then the automatic calls to sqlite3_initialize()
1627** are omitted and the application must call sqlite3_initialize() directly
1628** prior to using any other SQLite interface. For maximum portability,
1629** it is recommended that applications always invoke sqlite3_initialize()
1630** directly prior to using any other SQLite interface. Future releases
1631** of SQLite may require this. In other words, the behavior exhibited
1632** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1633** default behavior in some future release of SQLite.
1634**
1635** The sqlite3_os_init() routine does operating-system specific
1636** initialization of the SQLite library. The sqlite3_os_end()
1637** routine undoes the effect of sqlite3_os_init(). Typical tasks
1638** performed by these routines include allocation or deallocation
1639** of static resources, initialization of global variables,
1640** setting up a default [sqlite3_vfs] module, or setting up
1641** a default configuration using [sqlite3_config()].
1642**
1643** The application should never invoke either sqlite3_os_init()
1644** or sqlite3_os_end() directly. The application should only invoke
1645** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1646** interface is called automatically by sqlite3_initialize() and
1647** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1648** implementations for sqlite3_os_init() and sqlite3_os_end()
1649** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1650** When [custom builds | built for other platforms]
1651** (using the [SQLITE_OS_OTHER=1] compile-time
1652** option) the application must supply a suitable implementation for
1653** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1654** implementation of sqlite3_os_init() or sqlite3_os_end()
1655** must return [SQLITE_OK] on success and some other [error code] upon
1656** failure.
1657*/
1658SQLITE_API int sqlite3_initialize(void);
1659SQLITE_API int sqlite3_shutdown(void);
1660SQLITE_API int sqlite3_os_init(void);
1661SQLITE_API int sqlite3_os_end(void);
1662
1663/*
1664** CAPI3REF: Configuring The SQLite Library
1665**
1666** The sqlite3_config() interface is used to make global configuration
1667** changes to SQLite in order to tune SQLite to the specific needs of
1668** the application. The default configuration is recommended for most
1669** applications and so this routine is usually not necessary. It is
1670** provided to support rare applications with unusual needs.
1671**
1672** <b>The sqlite3_config() interface is not threadsafe. The application
1673** must ensure that no other SQLite interfaces are invoked by other
1674** threads while sqlite3_config() is running.</b>
1675**
1676** The first argument to sqlite3_config() is an integer
1677** [configuration option] that determines
1678** what property of SQLite is to be configured. Subsequent arguments
1679** vary depending on the [configuration option]
1680** in the first argument.
1681**
1682** For most configuration options, the sqlite3_config() interface
1683** may only be invoked prior to library initialization using
1684** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1685** The exceptional configuration options that may be invoked at any time
1686** are called "anytime configuration options".
1687** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1688** [sqlite3_shutdown()] with a first argument that is not an anytime
1689** configuration option, then the sqlite3_config() call will return SQLITE_MISUSE.
1690** Note, however, that ^sqlite3_config() can be called as part of the
1691** implementation of an application-defined [sqlite3_os_init()].
1692**
1693** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1694** ^If the option is unknown or SQLite is unable to set the option
1695** then this routine returns a non-zero [error code].
1696*/
1697SQLITE_API int sqlite3_config(int, ...);
1698
1699/*
1700** CAPI3REF: Configure database connections
1701** METHOD: sqlite3
1702**
1703** The sqlite3_db_config() interface is used to make configuration
1704** changes to a [database connection]. The interface is similar to
1705** [sqlite3_config()] except that the changes apply to a single
1706** [database connection] (specified in the first argument).
1707**
1708** The second argument to sqlite3_db_config(D,V,...) is the
1709** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1710** that indicates what aspect of the [database connection] is being configured.
1711** Subsequent arguments vary depending on the configuration verb.
1712**
1713** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1714** the call is considered successful.
1715*/
1716SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1717
1718/*
1719** CAPI3REF: Memory Allocation Routines
1720**
1721** An instance of this object defines the interface between SQLite
1722** and low-level memory allocation routines.
1723**
1724** This object is used in only one place in the SQLite interface.
1725** A pointer to an instance of this object is the argument to
1726** [sqlite3_config()] when the configuration option is
1727** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1728** By creating an instance of this object
1729** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1730** during configuration, an application can specify an alternative
1731** memory allocation subsystem for SQLite to use for all of its
1732** dynamic memory needs.
1733**
1734** Note that SQLite comes with several [built-in memory allocators]
1735** that are perfectly adequate for the overwhelming majority of applications
1736** and that this object is only useful to a tiny minority of applications
1737** with specialized memory allocation requirements. This object is
1738** also used during testing of SQLite in order to specify an alternative
1739** memory allocator that simulates memory out-of-memory conditions in
1740** order to verify that SQLite recovers gracefully from such
1741** conditions.
1742**
1743** The xMalloc, xRealloc, and xFree methods must work like the
1744** malloc(), realloc() and free() functions from the standard C library.
1745** ^SQLite guarantees that the second argument to
1746** xRealloc is always a value returned by a prior call to xRoundup.
1747**
1748** xSize should return the allocated size of a memory allocation
1749** previously obtained from xMalloc or xRealloc. The allocated size
1750** is always at least as big as the requested size but may be larger.
1751**
1752** The xRoundup method returns what would be the allocated size of
1753** a memory allocation given a particular requested size. Most memory
1754** allocators round up memory allocations at least to the next multiple
1755** of 8. Some allocators round up to a larger multiple or to a power of 2.
1756** Every memory allocation request coming in through [sqlite3_malloc()]
1757** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
1758** that causes the corresponding memory allocation to fail.
1759**
1760** The xInit method initializes the memory allocator. For example,
1761** it might allocate any required mutexes or initialize internal data
1762** structures. The xShutdown method is invoked (indirectly) by
1763** [sqlite3_shutdown()] and should deallocate any resources acquired
1764** by xInit. The pAppData pointer is used as the only parameter to
1765** xInit and xShutdown.
1766**
1767** SQLite holds the [SQLITE_MUTEX_STATIC_MAIN] mutex when it invokes
1768** the xInit method, so the xInit method need not be threadsafe. The
1769** xShutdown method is only called from [sqlite3_shutdown()] so it does
1770** not need to be threadsafe either. For all other methods, SQLite
1771** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1772** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1773** it is by default) and so the methods are automatically serialized.
1774** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1775** methods must be threadsafe or else make their own arrangements for
1776** serialization.
1777**
1778** SQLite will never invoke xInit() more than once without an intervening
1779** call to xShutdown().
1780*/
1781typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1782struct sqlite3_mem_methods {
1783 void *(*xMalloc)(int); /* Memory allocation function */
1784 void (*xFree)(void*); /* Free a prior allocation */
1785 void *(*xRealloc)(void*,int); /* Resize an allocation */
1786 int (*xSize)(void*); /* Return the size of an allocation */
1787 int (*xRoundup)(int); /* Round up request size to allocation size */
1788 int (*xInit)(void*); /* Initialize the memory allocator */
1789 void (*xShutdown)(void*); /* Deinitialize the memory allocator */
1790 void *pAppData; /* Argument to xInit() and xShutdown() */
1791};
1792
1793/*
1794** CAPI3REF: Configuration Options
1795** KEYWORDS: {configuration option}
1796**
1797** These constants are the available integer configuration options that
1798** can be passed as the first argument to the [sqlite3_config()] interface.
1799**
1800** Most of the configuration options for sqlite3_config()
1801** will only work if invoked prior to [sqlite3_initialize()] or after
1802** [sqlite3_shutdown()]. The few exceptions to this rule are called
1803** "anytime configuration options".
1804** ^Calling [sqlite3_config()] with a first argument that is not an
1805** anytime configuration option in between calls to [sqlite3_initialize()] and
1806** [sqlite3_shutdown()] is a no-op that returns SQLITE_MISUSE.
1807**
1808** The set of anytime configuration options can change (by insertions
1809** and/or deletions) from one release of SQLite to the next.
1810** As of SQLite version 3.42.0, the complete set of anytime configuration
1811** options is:
1812** <ul>
1813** <li> SQLITE_CONFIG_LOG
1814** <li> SQLITE_CONFIG_PCACHE_HDRSZ
1815** </ul>
1816**
1817** New configuration options may be added in future releases of SQLite.
1818** Existing configuration options might be discontinued. Applications
1819** should check the return code from [sqlite3_config()] to make sure that
1820** the call worked. The [sqlite3_config()] interface will return a
1821** non-zero [error code] if a discontinued or unsupported configuration option
1822** is invoked.
1823**
1824** <dl>
1825** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1826** <dd>There are no arguments to this option. ^This option sets the
1827** [threading mode] to Single-thread. In other words, it disables
1828** all mutexing and puts SQLite into a mode where it can only be used
1829** by a single thread. ^If SQLite is compiled with
1830** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1831** it is not possible to change the [threading mode] from its default
1832** value of Single-thread and so [sqlite3_config()] will return
1833** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1834** configuration option.</dd>
1835**
1836** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1837** <dd>There are no arguments to this option. ^This option sets the
1838** [threading mode] to Multi-thread. In other words, it disables
1839** mutexing on [database connection] and [prepared statement] objects.
1840** The application is responsible for serializing access to
1841** [database connections] and [prepared statements]. But other mutexes
1842** are enabled so that SQLite will be safe to use in a multi-threaded
1843** environment as long as no two threads attempt to use the same
1844** [database connection] at the same time. ^If SQLite is compiled with
1845** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1846** it is not possible to set the Multi-thread [threading mode] and
1847** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1848** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1849**
1850** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1851** <dd>There are no arguments to this option. ^This option sets the
1852** [threading mode] to Serialized. In other words, this option enables
1853** all mutexes including the recursive
1854** mutexes on [database connection] and [prepared statement] objects.
1855** In this mode (which is the default when SQLite is compiled with
1856** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1857** to [database connections] and [prepared statements] so that the
1858** application is free to use the same [database connection] or the
1859** same [prepared statement] in different threads at the same time.
1860** ^If SQLite is compiled with
1861** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1862** it is not possible to set the Serialized [threading mode] and
1863** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1864** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1865**
1866** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1867** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1868** a pointer to an instance of the [sqlite3_mem_methods] structure.
1869** The argument specifies
1870** alternative low-level memory allocation routines to be used in place of
1871** the memory allocation routines built into SQLite.)^ ^SQLite makes
1872** its own private copy of the content of the [sqlite3_mem_methods] structure
1873** before the [sqlite3_config()] call returns.</dd>
1874**
1875** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1876** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1877** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1878** The [sqlite3_mem_methods]
1879** structure is filled with the currently defined memory allocation routines.)^
1880** This option can be used to overload the default memory allocation
1881** routines with a wrapper that simulations memory allocation failure or
1882** tracks memory usage, for example. </dd>
1883**
1884** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
1885** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
1886** type int, interpreted as a boolean, which if true provides a hint to
1887** SQLite that it should avoid large memory allocations if possible.
1888** SQLite will run faster if it is free to make large memory allocations,
1889** but some application might prefer to run slower in exchange for
1890** guarantees about memory fragmentation that are possible if large
1891** allocations are avoided. This hint is normally off.
1892** </dd>
1893**
1894** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1895** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1896** interpreted as a boolean, which enables or disables the collection of
1897** memory allocation statistics. ^(When memory allocation statistics are
1898** disabled, the following SQLite interfaces become non-operational:
1899** <ul>
1900** <li> [sqlite3_hard_heap_limit64()]
1901** <li> [sqlite3_memory_used()]
1902** <li> [sqlite3_memory_highwater()]
1903** <li> [sqlite3_soft_heap_limit64()]
1904** <li> [sqlite3_status64()]
1905** </ul>)^
1906** ^Memory allocation statistics are enabled by default unless SQLite is
1907** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1908** allocation statistics are disabled by default.
1909** </dd>
1910**
1911** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1912** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
1913** </dd>
1914**
1915** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1916** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
1917** that SQLite can use for the database page cache with the default page
1918** cache implementation.
1919** This configuration option is a no-op if an application-defined page
1920** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
1921** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1922** 8-byte aligned memory (pMem), the size of each page cache line (sz),
1923** and the number of cache lines (N).
1924** The sz argument should be the size of the largest database page
1925** (a power of two between 512 and 65536) plus some extra bytes for each
1926** page header. ^The number of extra bytes needed by the page header
1927** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
1928** ^It is harmless, apart from the wasted memory,
1929** for the sz parameter to be larger than necessary. The pMem
1930** argument must be either a NULL pointer or a pointer to an 8-byte
1931** aligned block of memory of at least sz*N bytes, otherwise
1932** subsequent behavior is undefined.
1933** ^When pMem is not NULL, SQLite will strive to use the memory provided
1934** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
1935** a page cache line is larger than sz bytes or if all of the pMem buffer
1936** is exhausted.
1937** ^If pMem is NULL and N is non-zero, then each database connection
1938** does an initial bulk allocation for page cache memory
1939** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
1940** of -1024*N bytes if N is negative, . ^If additional
1941** page cache memory is needed beyond what is provided by the initial
1942** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
1943** additional cache line. </dd>
1944**
1945** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1946** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1947** that SQLite will use for all of its dynamic memory allocation needs
1948** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
1949** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1950** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1951** [SQLITE_ERROR] if invoked otherwise.
1952** ^There are three arguments to SQLITE_CONFIG_HEAP:
1953** An 8-byte aligned pointer to the memory,
1954** the number of bytes in the memory buffer, and the minimum allocation size.
1955** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1956** to using its default memory allocator (the system malloc() implementation),
1957** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
1958** memory pointer is not NULL then the alternative memory
1959** allocator is engaged to handle all of SQLites memory allocation needs.
1960** The first pointer (the memory pointer) must be aligned to an 8-byte
1961** boundary or subsequent behavior of SQLite will be undefined.
1962** The minimum allocation size is capped at 2**12. Reasonable values
1963** for the minimum allocation size are 2**5 through 2**8.</dd>
1964**
1965** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1966** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1967** pointer to an instance of the [sqlite3_mutex_methods] structure.
1968** The argument specifies alternative low-level mutex routines to be used
1969** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of
1970** the content of the [sqlite3_mutex_methods] structure before the call to
1971** [sqlite3_config()] returns. ^If SQLite is compiled with
1972** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1973** the entire mutexing subsystem is omitted from the build and hence calls to
1974** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1975** return [SQLITE_ERROR].</dd>
1976**
1977** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1978** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1979** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The
1980** [sqlite3_mutex_methods]
1981** structure is filled with the currently defined mutex routines.)^
1982** This option can be used to overload the default mutex allocation
1983** routines with a wrapper used to track mutex usage for performance
1984** profiling or testing, for example. ^If SQLite is compiled with
1985** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1986** the entire mutexing subsystem is omitted from the build and hence calls to
1987** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1988** return [SQLITE_ERROR].</dd>
1989**
1990** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1991** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1992** the default size of lookaside memory on each [database connection].
1993** The first argument is the
1994** size of each lookaside buffer slot and the second is the number of
1995** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE
1996** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1997** option to [sqlite3_db_config()] can be used to change the lookaside
1998** configuration on individual connections.)^ </dd>
1999**
2000** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
2001** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
2002** a pointer to an [sqlite3_pcache_methods2] object. This object specifies
2003** the interface to a custom page cache implementation.)^
2004** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
2005**
2006** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
2007** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
2008** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of
2009** the current page cache implementation into that object.)^ </dd>
2010**
2011** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
2012** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
2013** global [error log].
2014** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
2015** function with a call signature of void(*)(void*,int,const char*),
2016** and a pointer to void. ^If the function pointer is not NULL, it is
2017** invoked by [sqlite3_log()] to process each logging event. ^If the
2018** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
2019** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
2020** passed through as the first parameter to the application-defined logger
2021** function whenever that function is invoked. ^The second parameter to
2022** the logger function is a copy of the first parameter to the corresponding
2023** [sqlite3_log()] call and is intended to be a [result code] or an
2024** [extended result code]. ^The third parameter passed to the logger is
2025** log message after formatting via [sqlite3_snprintf()].
2026** The SQLite logging interface is not reentrant; the logger function
2027** supplied by the application must not invoke any SQLite interface.
2028** In a multi-threaded application, the application-defined logger
2029** function must be threadsafe. </dd>
2030**
2031** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
2032** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
2033** If non-zero, then URI handling is globally enabled. If the parameter is zero,
2034** then URI handling is globally disabled.)^ ^If URI handling is globally
2035** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
2036** [sqlite3_open16()] or
2037** specified as part of [ATTACH] commands are interpreted as URIs, regardless
2038** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
2039** connection is opened. ^If it is globally disabled, filenames are
2040** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
2041** database connection is opened. ^(By default, URI handling is globally
2042** disabled. The default value may be changed by compiling with the
2043** [SQLITE_USE_URI] symbol defined.)^
2044**
2045** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
2046** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
2047** argument which is interpreted as a boolean in order to enable or disable
2048** the use of covering indices for full table scans in the query optimizer.
2049** ^The default setting is determined
2050** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
2051** if that compile-time option is omitted.
2052** The ability to disable the use of covering indices for full table scans
2053** is because some incorrectly coded legacy applications might malfunction
2054** when the optimization is enabled. Providing the ability to
2055** disable the optimization allows the older, buggy application code to work
2056** without change even with newer versions of SQLite.
2057**
2058** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
2059** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
2060** <dd> These options are obsolete and should not be used by new code.
2061** They are retained for backwards compatibility but are now no-ops.
2062** </dd>
2063**
2064** [[SQLITE_CONFIG_SQLLOG]]
2065** <dt>SQLITE_CONFIG_SQLLOG
2066** <dd>This option is only available if sqlite is compiled with the
2067** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
2068** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
2069** The second should be of type (void*). The callback is invoked by the library
2070** in three separate circumstances, identified by the value passed as the
2071** fourth parameter. If the fourth parameter is 0, then the database connection
2072** passed as the second argument has just been opened. The third argument
2073** points to a buffer containing the name of the main database file. If the
2074** fourth parameter is 1, then the SQL statement that the third parameter
2075** points to has just been executed. Or, if the fourth parameter is 2, then
2076** the connection being passed as the second parameter is being closed. The
2077** third parameter is passed NULL In this case. An example of using this
2078** configuration option can be seen in the "test_sqllog.c" source file in
2079** the canonical SQLite source tree.</dd>
2080**
2081** [[SQLITE_CONFIG_MMAP_SIZE]]
2082** <dt>SQLITE_CONFIG_MMAP_SIZE
2083** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
2084** that are the default mmap size limit (the default setting for
2085** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
2086** ^The default setting can be overridden by each database connection using
2087** either the [PRAGMA mmap_size] command, or by using the
2088** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size
2089** will be silently truncated if necessary so that it does not exceed the
2090** compile-time maximum mmap size set by the
2091** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
2092** ^If either argument to this option is negative, then that argument is
2093** changed to its compile-time default.
2094**
2095** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
2096** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
2097** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
2098** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
2099** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
2100** that specifies the maximum size of the created heap.
2101**
2102** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
2103** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
2104** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
2105** is a pointer to an integer and writes into that integer the number of extra
2106** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
2107** The amount of extra space required can change depending on the compiler,
2108** target platform, and SQLite version.
2109**
2110** [[SQLITE_CONFIG_PMASZ]]
2111** <dt>SQLITE_CONFIG_PMASZ
2112** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
2113** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
2114** sorter to that integer. The default minimum PMA Size is set by the
2115** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched
2116** to help with sort operations when multithreaded sorting
2117** is enabled (using the [PRAGMA threads] command) and the amount of content
2118** to be sorted exceeds the page size times the minimum of the
2119** [PRAGMA cache_size] setting and this value.
2120**
2121** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
2122** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
2123** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
2124** becomes the [statement journal] spill-to-disk threshold.
2125** [Statement journals] are held in memory until their size (in bytes)
2126** exceeds this threshold, at which point they are written to disk.
2127** Or if the threshold is -1, statement journals are always held
2128** exclusively in memory.
2129** Since many statement journals never become large, setting the spill
2130** threshold to a value such as 64KiB can greatly reduce the amount of
2131** I/O required to support statement rollback.
2132** The default value for this setting is controlled by the
2133** [SQLITE_STMTJRNL_SPILL] compile-time option.
2134**
2135** [[SQLITE_CONFIG_SORTERREF_SIZE]]
2136** <dt>SQLITE_CONFIG_SORTERREF_SIZE
2137** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
2138** of type (int) - the new value of the sorter-reference size threshold.
2139** Usually, when SQLite uses an external sort to order records according
2140** to an ORDER BY clause, all fields required by the caller are present in the
2141** sorted records. However, if SQLite determines based on the declared type
2142** of a table column that its values are likely to be very large - larger
2143** than the configured sorter-reference size threshold - then a reference
2144** is stored in each sorted record and the required column values loaded
2145** from the database as records are returned in sorted order. The default
2146** value for this option is to never use this optimization. Specifying a
2147** negative value for this option restores the default behavior.
2148** This option is only available if SQLite is compiled with the
2149** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option.
2150**
2151** [[SQLITE_CONFIG_MEMDB_MAXSIZE]]
2152** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE
2153** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter
2154** [sqlite3_int64] parameter which is the default maximum size for an in-memory
2155** database created using [sqlite3_deserialize()]. This default maximum
2156** size can be adjusted up or down for individual databases using the
2157** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control]. If this
2158** configuration setting is never used, then the default maximum is determined
2159** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option. If that
2160** compile-time option is not set, then the default maximum is 1073741824.
2161**
2162** [[SQLITE_CONFIG_ROWID_IN_VIEW]]
2163** <dt>SQLITE_CONFIG_ROWID_IN_VIEW
2164** <dd>The SQLITE_CONFIG_ROWID_IN_VIEW option enables or disables the ability
2165** for VIEWs to have a ROWID. The capability can only be enabled if SQLite is
2166** compiled with -DSQLITE_ALLOW_ROWID_IN_VIEW, in which case the capability
2167** defaults to on. This configuration option queries the current setting or
2168** changes the setting to off or on. The argument is a pointer to an integer.
2169** If that integer initially holds a value of 1, then the ability for VIEWs to
2170** have ROWIDs is activated. If the integer initially holds zero, then the
2171** ability is deactivated. Any other initial value for the integer leaves the
2172** setting unchanged. After changes, if any, the integer is written with
2173** a 1 or 0, if the ability for VIEWs to have ROWIDs is on or off. If SQLite
2174** is compiled without -DSQLITE_ALLOW_ROWID_IN_VIEW (which is the usual and
2175** recommended case) then the integer is always filled with zero, regardless
2176** if its initial value.
2177** </dl>
2178*/
2179#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
2180#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
2181#define SQLITE_CONFIG_SERIALIZED 3 /* nil */
2182#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
2183#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
2184#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */
2185#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
2186#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
2187#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
2188#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
2189#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
2190/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
2191#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
2192#define SQLITE_CONFIG_PCACHE 14 /* no-op */
2193#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
2194#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
2195#define SQLITE_CONFIG_URI 17 /* int */
2196#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
2197#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
2198#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
2199#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
2200#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */
2201#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */
2202#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */
2203#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */
2204#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */
2205#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */
2206#define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */
2207#define SQLITE_CONFIG_MEMDB_MAXSIZE 29 /* sqlite3_int64 */
2208#define SQLITE_CONFIG_ROWID_IN_VIEW 30 /* int* */
2209
2210/*
2211** CAPI3REF: Database Connection Configuration Options
2212**
2213** These constants are the available integer configuration options that
2214** can be passed as the second parameter to the [sqlite3_db_config()] interface.
2215**
2216** The [sqlite3_db_config()] interface is a var-args functions. It takes a
2217** variable number of parameters, though always at least two. The number of
2218** parameters passed into sqlite3_db_config() depends on which of these
2219** constants is given as the second parameter. This documentation page
2220** refers to parameters beyond the second as "arguments". Thus, when this
2221** page says "the N-th argument" it means "the N-th parameter past the
2222** configuration option" or "the (N+2)-th parameter to sqlite3_db_config()".
2223**
2224** New configuration options may be added in future releases of SQLite.
2225** Existing configuration options might be discontinued. Applications
2226** should check the return code from [sqlite3_db_config()] to make sure that
2227** the call worked. ^The [sqlite3_db_config()] interface will return a
2228** non-zero [error code] if a discontinued or unsupported configuration option
2229** is invoked.
2230**
2231** <dl>
2232** [[SQLITE_DBCONFIG_LOOKASIDE]]
2233** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
2234** <dd> The SQLITE_DBCONFIG_LOOKASIDE option is used to adjust the
2235** configuration of the lookaside memory allocator within a database
2236** connection.
2237** The arguments to the SQLITE_DBCONFIG_LOOKASIDE option are <i>not</i>
2238** in the [DBCONFIG arguments|usual format].
2239** The SQLITE_DBCONFIG_LOOKASIDE option takes three arguments, not two,
2240** so that a call to [sqlite3_db_config()] that uses SQLITE_DBCONFIG_LOOKASIDE
2241** should have a total of five parameters.
2242** ^The first argument (the third parameter to [sqlite3_db_config()] is a
2243** pointer to a memory buffer to use for lookaside memory.
2244** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
2245** may be NULL in which case SQLite will allocate the
2246** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
2247** size of each lookaside buffer slot. ^The third argument is the number of
2248** slots. The size of the buffer in the first argument must be greater than
2249** or equal to the product of the second and third arguments. The buffer
2250** must be aligned to an 8-byte boundary. ^If the second argument to
2251** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
2252** rounded down to the next smaller multiple of 8. ^(The lookaside memory
2253** configuration for a database connection can only be changed when that
2254** connection is not currently using lookaside memory, or in other words
2255** when the "current value" returned by
2256** [sqlite3_db_status](D,[SQLITE_DBSTATUS_LOOKASIDE_USED],...) is zero.
2257** Any attempt to change the lookaside memory configuration when lookaside
2258** memory is in use leaves the configuration unchanged and returns
2259** [SQLITE_BUSY].)^</dd>
2260**
2261** [[SQLITE_DBCONFIG_ENABLE_FKEY]]
2262** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
2263** <dd> ^This option is used to enable or disable the enforcement of
2264** [foreign key constraints]. This is the same setting that is
2265** enabled or disabled by the [PRAGMA foreign_keys] statement.
2266** The first argument is an integer which is 0 to disable FK enforcement,
2267** positive to enable FK enforcement or negative to leave FK enforcement
2268** unchanged. The second parameter is a pointer to an integer into which
2269** is written 0 or 1 to indicate whether FK enforcement is off or on
2270** following this call. The second parameter may be a NULL pointer, in
2271** which case the FK enforcement setting is not reported back. </dd>
2272**
2273** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]]
2274** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
2275** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
2276** There should be two additional arguments.
2277** The first argument is an integer which is 0 to disable triggers,
2278** positive to enable triggers or negative to leave the setting unchanged.
2279** The second parameter is a pointer to an integer into which
2280** is written 0 or 1 to indicate whether triggers are disabled or enabled
2281** following this call. The second parameter may be a NULL pointer, in
2282** which case the trigger setting is not reported back.
2283**
2284** <p>Originally this option disabled all triggers. ^(However, since
2285** SQLite version 3.35.0, TEMP triggers are still allowed even if
2286** this option is off. So, in other words, this option now only disables
2287** triggers in the main database schema or in the schemas of [ATTACH]-ed
2288** databases.)^ </dd>
2289**
2290** [[SQLITE_DBCONFIG_ENABLE_VIEW]]
2291** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt>
2292** <dd> ^This option is used to enable or disable [CREATE VIEW | views].
2293** There must be two additional arguments.
2294** The first argument is an integer which is 0 to disable views,
2295** positive to enable views or negative to leave the setting unchanged.
2296** The second parameter is a pointer to an integer into which
2297** is written 0 or 1 to indicate whether views are disabled or enabled
2298** following this call. The second parameter may be a NULL pointer, in
2299** which case the view setting is not reported back.
2300**
2301** <p>Originally this option disabled all views. ^(However, since
2302** SQLite version 3.35.0, TEMP views are still allowed even if
2303** this option is off. So, in other words, this option now only disables
2304** views in the main database schema or in the schemas of ATTACH-ed
2305** databases.)^ </dd>
2306**
2307** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]]
2308** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
2309** <dd> ^This option is used to enable or disable the
2310** [fts3_tokenizer()] function which is part of the
2311** [FTS3] full-text search engine extension.
2312** There must be two additional arguments.
2313** The first argument is an integer which is 0 to disable fts3_tokenizer() or
2314** positive to enable fts3_tokenizer() or negative to leave the setting
2315** unchanged.
2316** The second parameter is a pointer to an integer into which
2317** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
2318** following this call. The second parameter may be a NULL pointer, in
2319** which case the new setting is not reported back. </dd>
2320**
2321** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]]
2322** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
2323** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
2324** interface independently of the [load_extension()] SQL function.
2325** The [sqlite3_enable_load_extension()] API enables or disables both the
2326** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
2327** There must be two additional arguments.
2328** When the first argument to this interface is 1, then only the C-API is
2329** enabled and the SQL function remains disabled. If the first argument to
2330** this interface is 0, then both the C-API and the SQL function are disabled.
2331** If the first argument is -1, then no changes are made to state of either the
2332** C-API or the SQL function.
2333** The second parameter is a pointer to an integer into which
2334** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
2335** is disabled or enabled following this call. The second parameter may
2336** be a NULL pointer, in which case the new setting is not reported back.
2337** </dd>
2338**
2339** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
2340** <dd> ^This option is used to change the name of the "main" database
2341** schema. This option does not follow the
2342** [DBCONFIG arguments|usual SQLITE_DBCONFIG argument format].
2343** This option takes exactly one additional argument so that the
2344** [sqlite3_db_config()] call has a total of three parameters. The
2345** extra argument must be a pointer to a constant UTF8 string which
2346** will become the new schema name in place of "main". ^SQLite does
2347** not make a copy of the new main schema name string, so the application
2348** must ensure that the argument passed into SQLITE_DBCONFIG MAINDBNAME
2349** is unchanged until after the database connection closes.
2350** </dd>
2351**
2352** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]]
2353** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
2354** <dd> Usually, when a database in [WAL mode] is closed or detached from a
2355** database handle, SQLite checks if if there are other connections to the
2356** same database, and if there are no other database connection (if the
2357** connection being closed is the last open connection to the database),
2358** then SQLite performs a [checkpoint] before closing the connection and
2359** deletes the WAL file. The SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE option can
2360** be used to override that behavior. The first argument passed to this
2361** operation (the third parameter to [sqlite3_db_config()]) is an integer
2362** which is positive to disable checkpoints-on-close, or zero (the default)
2363** to enable them, and negative to leave the setting unchanged.
2364** The second argument (the fourth parameter) is a pointer to an integer
2365** into which is written 0 or 1 to indicate whether checkpoints-on-close
2366** have been disabled - 0 if they are not disabled, 1 if they are.
2367** </dd>
2368**
2369** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
2370** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
2371** the [query planner stability guarantee] (QPSG). When the QPSG is active,
2372** a single SQL query statement will always use the same algorithm regardless
2373** of values of [bound parameters].)^ The QPSG disables some query optimizations
2374** that look at the values of bound parameters, which can make some queries
2375** slower. But the QPSG has the advantage of more predictable behavior. With
2376** the QPSG active, SQLite will always use the same query plan in the field as
2377** was used during testing in the lab.
2378** The first argument to this setting is an integer which is 0 to disable
2379** the QPSG, positive to enable QPSG, or negative to leave the setting
2380** unchanged. The second parameter is a pointer to an integer into which
2381** is written 0 or 1 to indicate whether the QPSG is disabled or enabled
2382** following this call.
2383** </dd>
2384**
2385** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
2386** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not
2387** include output for any operations performed by trigger programs. This
2388** option is used to set or clear (the default) a flag that governs this
2389** behavior. The first parameter passed to this operation is an integer -
2390** positive to enable output for trigger programs, or zero to disable it,
2391** or negative to leave the setting unchanged.
2392** The second parameter is a pointer to an integer into which is written
2393** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
2394** it is not disabled, 1 if it is.
2395** </dd>
2396**
2397** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt>
2398** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
2399** [VACUUM] in order to reset a database back to an empty database
2400** with no schema and no content. The following process works even for
2401** a badly corrupted database file:
2402** <ol>
2403** <li> If the database connection is newly opened, make sure it has read the
2404** database schema by preparing then discarding some query against the
2405** database, or calling sqlite3_table_column_metadata(), ignoring any
2406** errors. This step is only necessary if the application desires to keep
2407** the database in WAL mode after the reset if it was in WAL mode before
2408** the reset.
2409** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
2410** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0);
2411** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
2412** </ol>
2413** Because resetting a database is destructive and irreversible, the
2414** process requires the use of this obscure API and multiple steps to
2415** help ensure that it does not happen by accident. Because this
2416** feature must be capable of resetting corrupt databases, and
2417** shutting down virtual tables may require access to that corrupt
2418** storage, the library must abandon any installed virtual tables
2419** without calling their xDestroy() methods.
2420**
2421** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt>
2422** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the
2423** "defensive" flag for a database connection. When the defensive
2424** flag is enabled, language features that allow ordinary SQL to
2425** deliberately corrupt the database file are disabled. The disabled
2426** features include but are not limited to the following:
2427** <ul>
2428** <li> The [PRAGMA writable_schema=ON] statement.
2429** <li> The [PRAGMA journal_mode=OFF] statement.
2430** <li> The [PRAGMA schema_version=N] statement.
2431** <li> Writes to the [sqlite_dbpage] virtual table.
2432** <li> Direct writes to [shadow tables].
2433** </ul>
2434** </dd>
2435**
2436** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt>
2437** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the
2438** "writable_schema" flag. This has the same effect and is logically equivalent
2439** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF].
2440** The first argument to this setting is an integer which is 0 to disable
2441** the writable_schema, positive to enable writable_schema, or negative to
2442** leave the setting unchanged. The second parameter is a pointer to an
2443** integer into which is written 0 or 1 to indicate whether the writable_schema
2444** is enabled or disabled following this call.
2445** </dd>
2446**
2447** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]]
2448** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt>
2449** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates
2450** the legacy behavior of the [ALTER TABLE RENAME] command such it
2451** behaves as it did prior to [version 3.24.0] (2018-06-04). See the
2452** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for
2453** additional information. This feature can also be turned on and off
2454** using the [PRAGMA legacy_alter_table] statement.
2455** </dd>
2456**
2457** [[SQLITE_DBCONFIG_DQS_DML]]
2458** <dt>SQLITE_DBCONFIG_DQS_DML</dt>
2459** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates
2460** the legacy [double-quoted string literal] misfeature for DML statements
2461** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The
2462** default value of this setting is determined by the [-DSQLITE_DQS]
2463** compile-time option.
2464** </dd>
2465**
2466** [[SQLITE_DBCONFIG_DQS_DDL]]
2467** <dt>SQLITE_DBCONFIG_DQS_DDL</dt>
2468** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates
2469** the legacy [double-quoted string literal] misfeature for DDL statements,
2470** such as CREATE TABLE and CREATE INDEX. The
2471** default value of this setting is determined by the [-DSQLITE_DQS]
2472** compile-time option.
2473** </dd>
2474**
2475** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]]
2476** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</dt>
2477** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to
2478** assume that database schemas are untainted by malicious content.
2479** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite
2480** takes additional defensive steps to protect the application from harm
2481** including:
2482** <ul>
2483** <li> Prohibit the use of SQL functions inside triggers, views,
2484** CHECK constraints, DEFAULT clauses, expression indexes,
2485** partial indexes, or generated columns
2486** unless those functions are tagged with [SQLITE_INNOCUOUS].
2487** <li> Prohibit the use of virtual tables inside of triggers or views
2488** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS].
2489** </ul>
2490** This setting defaults to "on" for legacy compatibility, however
2491** all applications are advised to turn it off if possible. This setting
2492** can also be controlled using the [PRAGMA trusted_schema] statement.
2493** </dd>
2494**
2495** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]]
2496** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</dt>
2497** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates
2498** the legacy file format flag. When activated, this flag causes all newly
2499** created database file to have a schema format version number (the 4-byte
2500** integer found at offset 44 into the database header) of 1. This in turn
2501** means that the resulting database file will be readable and writable by
2502** any SQLite version back to 3.0.0 ([dateof:3.0.0]). Without this setting,
2503** newly created databases are generally not understandable by SQLite versions
2504** prior to 3.3.0 ([dateof:3.3.0]). As these words are written, there
2505** is now scarcely any need to generate database files that are compatible
2506** all the way back to version 3.0.0, and so this setting is of little
2507** practical use, but is provided so that SQLite can continue to claim the
2508** ability to generate new database files that are compatible with version
2509** 3.0.0.
2510** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on,
2511** the [VACUUM] command will fail with an obscure error when attempting to
2512** process a table with generated columns and a descending index. This is
2513** not considered a bug since SQLite versions 3.3.0 and earlier do not support
2514** either generated columns or descending indexes.
2515** </dd>
2516**
2517** [[SQLITE_DBCONFIG_STMT_SCANSTATUS]]
2518** <dt>SQLITE_DBCONFIG_STMT_SCANSTATUS</dt>
2519** <dd>The SQLITE_DBCONFIG_STMT_SCANSTATUS option is only useful in
2520** SQLITE_ENABLE_STMT_SCANSTATUS builds. In this case, it sets or clears
2521** a flag that enables collection of the sqlite3_stmt_scanstatus_v2()
2522** statistics. For statistics to be collected, the flag must be set on
2523** the database handle both when the SQL statement is prepared and when it
2524** is stepped. The flag is set (collection of statistics is enabled)
2525** by default. <p>This option takes two arguments: an integer and a pointer to
2526** an integer.. The first argument is 1, 0, or -1 to enable, disable, or
2527** leave unchanged the statement scanstatus option. If the second argument
2528** is not NULL, then the value of the statement scanstatus setting after
2529** processing the first argument is written into the integer that the second
2530** argument points to.
2531** </dd>
2532**
2533** [[SQLITE_DBCONFIG_REVERSE_SCANORDER]]
2534** <dt>SQLITE_DBCONFIG_REVERSE_SCANORDER</dt>
2535** <dd>The SQLITE_DBCONFIG_REVERSE_SCANORDER option changes the default order
2536** in which tables and indexes are scanned so that the scans start at the end
2537** and work toward the beginning rather than starting at the beginning and
2538** working toward the end. Setting SQLITE_DBCONFIG_REVERSE_SCANORDER is the
2539** same as setting [PRAGMA reverse_unordered_selects]. <p>This option takes
2540** two arguments which are an integer and a pointer to an integer. The first
2541** argument is 1, 0, or -1 to enable, disable, or leave unchanged the
2542** reverse scan order flag, respectively. If the second argument is not NULL,
2543** then 0 or 1 is written into the integer that the second argument points to
2544** depending on if the reverse scan order flag is set after processing the
2545** first argument.
2546** </dd>
2547**
2548** [[SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE]]
2549** <dt>SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE</dt>
2550** <dd>The SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE option enables or disables
2551** the ability of the [ATTACH DATABASE] SQL command to create a new database
2552** file if the database filed named in the ATTACH command does not already
2553** exist. This ability of ATTACH to create a new database is enabled by
2554** default. Applications can disable or reenable the ability for ATTACH to
2555** create new database files using this DBCONFIG option.<p>
2556** This option takes two arguments which are an integer and a pointer
2557** to an integer. The first argument is 1, 0, or -1 to enable, disable, or
2558** leave unchanged the attach-create flag, respectively. If the second
2559** argument is not NULL, then 0 or 1 is written into the integer that the
2560** second argument points to depending on if the attach-create flag is set
2561** after processing the first argument.
2562** </dd>
2563**
2564** [[SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE]]
2565** <dt>SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE</dt>
2566** <dd>The SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE option enables or disables the
2567** ability of the [ATTACH DATABASE] SQL command to open a database for writing.
2568** This capability is enabled by default. Applications can disable or
2569** reenable this capability using the current DBCONFIG option. If the
2570** the this capability is disabled, the [ATTACH] command will still work,
2571** but the database will be opened read-only. If this option is disabled,
2572** then the ability to create a new database using [ATTACH] is also disabled,
2573** regardless of the value of the [SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE]
2574** option.<p>
2575** This option takes two arguments which are an integer and a pointer
2576** to an integer. The first argument is 1, 0, or -1 to enable, disable, or
2577** leave unchanged the ability to ATTACH another database for writing,
2578** respectively. If the second argument is not NULL, then 0 or 1 is written
2579** into the integer to which the second argument points, depending on whether
2580** the ability to ATTACH a read/write database is enabled or disabled
2581** after processing the first argument.
2582** </dd>
2583**
2584** [[SQLITE_DBCONFIG_ENABLE_COMMENTS]]
2585** <dt>SQLITE_DBCONFIG_ENABLE_COMMENTS</dt>
2586** <dd>The SQLITE_DBCONFIG_ENABLE_COMMENTS option enables or disables the
2587** ability to include comments in SQL text. Comments are enabled by default.
2588** An application can disable or reenable comments in SQL text using this
2589** DBCONFIG option.<p>
2590** This option takes two arguments which are an integer and a pointer
2591** to an integer. The first argument is 1, 0, or -1 to enable, disable, or
2592** leave unchanged the ability to use comments in SQL text,
2593** respectively. If the second argument is not NULL, then 0 or 1 is written
2594** into the integer that the second argument points to depending on if
2595** comments are allowed in SQL text after processing the first argument.
2596** </dd>
2597**
2598** </dl>
2599**
2600** [[DBCONFIG arguments]] <h3>Arguments To SQLITE_DBCONFIG Options</h3>
2601**
2602** <p>Most of the SQLITE_DBCONFIG options take two arguments, so that the
2603** overall call to [sqlite3_db_config()] has a total of four parameters.
2604** The first argument (the third parameter to sqlite3_db_config()) is a integer.
2605** The second argument is a pointer to an integer. If the first argument is 1,
2606** then the option becomes enabled. If the first integer argument is 0, then the
2607** option is disabled. If the first argument is -1, then the option setting
2608** is unchanged. The second argument, the pointer to an integer, may be NULL.
2609** If the second argument is not NULL, then a value of 0 or 1 is written into
2610** the integer to which the second argument points, depending on whether the
2611** setting is disabled or enabled after applying any changes specified by
2612** the first argument.
2613**
2614** <p>While most SQLITE_DBCONFIG options use the argument format
2615** described in the previous paragraph, the [SQLITE_DBCONFIG_MAINDBNAME]
2616** and [SQLITE_DBCONFIG_LOOKASIDE] options are different. See the
2617** documentation of those exceptional options for details.
2618*/
2619#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */
2620#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
2621#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
2622#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
2623#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
2624#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
2625#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */
2626#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */
2627#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */
2628#define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */
2629#define SQLITE_DBCONFIG_DEFENSIVE 1010 /* int int* */
2630#define SQLITE_DBCONFIG_WRITABLE_SCHEMA 1011 /* int int* */
2631#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE 1012 /* int int* */
2632#define SQLITE_DBCONFIG_DQS_DML 1013 /* int int* */
2633#define SQLITE_DBCONFIG_DQS_DDL 1014 /* int int* */
2634#define SQLITE_DBCONFIG_ENABLE_VIEW 1015 /* int int* */
2635#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT 1016 /* int int* */
2636#define SQLITE_DBCONFIG_TRUSTED_SCHEMA 1017 /* int int* */
2637#define SQLITE_DBCONFIG_STMT_SCANSTATUS 1018 /* int int* */
2638#define SQLITE_DBCONFIG_REVERSE_SCANORDER 1019 /* int int* */
2639#define SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE 1020 /* int int* */
2640#define SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE 1021 /* int int* */
2641#define SQLITE_DBCONFIG_ENABLE_COMMENTS 1022 /* int int* */
2642#define SQLITE_DBCONFIG_MAX 1022 /* Largest DBCONFIG */
2643
2644/*
2645** CAPI3REF: Enable Or Disable Extended Result Codes
2646** METHOD: sqlite3
2647**
2648** ^The sqlite3_extended_result_codes() routine enables or disables the
2649** [extended result codes] feature of SQLite. ^The extended result
2650** codes are disabled by default for historical compatibility.
2651*/
2652SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
2653
2654/*
2655** CAPI3REF: Last Insert Rowid
2656** METHOD: sqlite3
2657**
2658** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
2659** has a unique 64-bit signed
2660** integer key called the [ROWID | "rowid"]. ^The rowid is always available
2661** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
2662** names are not also used by explicitly declared columns. ^If
2663** the table has a column of type [INTEGER PRIMARY KEY] then that column
2664** is another alias for the rowid.
2665**
2666** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
2667** the most recent successful [INSERT] into a rowid table or [virtual table]
2668** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
2669** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
2670** on the database connection D, then sqlite3_last_insert_rowid(D) returns
2671** zero.
2672**
2673** As well as being set automatically as rows are inserted into database
2674** tables, the value returned by this function may be set explicitly by
2675** [sqlite3_set_last_insert_rowid()]
2676**
2677** Some virtual table implementations may INSERT rows into rowid tables as
2678** part of committing a transaction (e.g. to flush data accumulated in memory
2679** to disk). In this case subsequent calls to this function return the rowid
2680** associated with these internal INSERT operations, which leads to
2681** unintuitive results. Virtual table implementations that do write to rowid
2682** tables in this way can avoid this problem by restoring the original
2683** rowid value using [sqlite3_set_last_insert_rowid()] before returning
2684** control to the user.
2685**
2686** ^(If an [INSERT] occurs within a trigger then this routine will
2687** return the [rowid] of the inserted row as long as the trigger is
2688** running. Once the trigger program ends, the value returned
2689** by this routine reverts to what it was before the trigger was fired.)^
2690**
2691** ^An [INSERT] that fails due to a constraint violation is not a
2692** successful [INSERT] and does not change the value returned by this
2693** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
2694** and INSERT OR ABORT make no changes to the return value of this
2695** routine when their insertion fails. ^(When INSERT OR REPLACE
2696** encounters a constraint violation, it does not fail. The
2697** INSERT continues to completion after deleting rows that caused
2698** the constraint problem so INSERT OR REPLACE will always change
2699** the return value of this interface.)^
2700**
2701** ^For the purposes of this routine, an [INSERT] is considered to
2702** be successful even if it is subsequently rolled back.
2703**
2704** This function is accessible to SQL statements via the
2705** [last_insert_rowid() SQL function].
2706**
2707** If a separate thread performs a new [INSERT] on the same
2708** database connection while the [sqlite3_last_insert_rowid()]
2709** function is running and thus changes the last insert [rowid],
2710** then the value returned by [sqlite3_last_insert_rowid()] is
2711** unpredictable and might not equal either the old or the new
2712** last insert [rowid].
2713*/
2714SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
2715
2716/*
2717** CAPI3REF: Set the Last Insert Rowid value.
2718** METHOD: sqlite3
2719**
2720** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
2721** set the value returned by calling sqlite3_last_insert_rowid(D) to R
2722** without inserting a row into the database.
2723*/
2724SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
2725
2726/*
2727** CAPI3REF: Count The Number Of Rows Modified
2728** METHOD: sqlite3
2729**
2730** ^These functions return the number of rows modified, inserted or
2731** deleted by the most recently completed INSERT, UPDATE or DELETE
2732** statement on the database connection specified by the only parameter.
2733** The two functions are identical except for the type of the return value
2734** and that if the number of rows modified by the most recent INSERT, UPDATE,
2735** or DELETE is greater than the maximum value supported by type "int", then
2736** the return value of sqlite3_changes() is undefined. ^Executing any other
2737** type of SQL statement does not modify the value returned by these functions.
2738** For the purposes of this interface, a CREATE TABLE AS SELECT statement
2739** does not count as an INSERT, UPDATE or DELETE statement and hence the rows
2740** added to the new table by the CREATE TABLE AS SELECT statement are not
2741** counted.
2742**
2743** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
2744** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
2745** [foreign key actions] or [REPLACE] constraint resolution are not counted.
2746**
2747** Changes to a view that are intercepted by
2748** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
2749** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
2750** DELETE statement run on a view is always zero. Only changes made to real
2751** tables are counted.
2752**
2753** Things are more complicated if the sqlite3_changes() function is
2754** executed while a trigger program is running. This may happen if the
2755** program uses the [changes() SQL function], or if some other callback
2756** function invokes sqlite3_changes() directly. Essentially:
2757**
2758** <ul>
2759** <li> ^(Before entering a trigger program the value returned by
2760** sqlite3_changes() function is saved. After the trigger program
2761** has finished, the original value is restored.)^
2762**
2763** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
2764** statement sets the value returned by sqlite3_changes()
2765** upon completion as normal. Of course, this value will not include
2766** any changes performed by sub-triggers, as the sqlite3_changes()
2767** value will be saved and restored after each sub-trigger has run.)^
2768** </ul>
2769**
2770** ^This means that if the changes() SQL function (or similar) is used
2771** by the first INSERT, UPDATE or DELETE statement within a trigger, it
2772** returns the value as set when the calling statement began executing.
2773** ^If it is used by the second or subsequent such statement within a trigger
2774** program, the value returned reflects the number of rows modified by the
2775** previous INSERT, UPDATE or DELETE statement within the same trigger.
2776**
2777** If a separate thread makes changes on the same database connection
2778** while [sqlite3_changes()] is running then the value returned
2779** is unpredictable and not meaningful.
2780**
2781** See also:
2782** <ul>
2783** <li> the [sqlite3_total_changes()] interface
2784** <li> the [count_changes pragma]
2785** <li> the [changes() SQL function]
2786** <li> the [data_version pragma]
2787** </ul>
2788*/
2789SQLITE_API int sqlite3_changes(sqlite3*);
2790SQLITE_API sqlite3_int64 sqlite3_changes64(sqlite3*);
2791
2792/*
2793** CAPI3REF: Total Number Of Rows Modified
2794** METHOD: sqlite3
2795**
2796** ^These functions return the total number of rows inserted, modified or
2797** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2798** since the database connection was opened, including those executed as
2799** part of trigger programs. The two functions are identical except for the
2800** type of the return value and that if the number of rows modified by the
2801** connection exceeds the maximum value supported by type "int", then
2802** the return value of sqlite3_total_changes() is undefined. ^Executing
2803** any other type of SQL statement does not affect the value returned by
2804** sqlite3_total_changes().
2805**
2806** ^Changes made as part of [foreign key actions] are included in the
2807** count, but those made as part of REPLACE constraint resolution are
2808** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2809** are not counted.
2810**
2811** The [sqlite3_total_changes(D)] interface only reports the number
2812** of rows that changed due to SQL statement run against database
2813** connection D. Any changes by other database connections are ignored.
2814** To detect changes against a database file from other database
2815** connections use the [PRAGMA data_version] command or the
2816** [SQLITE_FCNTL_DATA_VERSION] [file control].
2817**
2818** If a separate thread makes changes on the same database connection
2819** while [sqlite3_total_changes()] is running then the value
2820** returned is unpredictable and not meaningful.
2821**
2822** See also:
2823** <ul>
2824** <li> the [sqlite3_changes()] interface
2825** <li> the [count_changes pragma]
2826** <li> the [changes() SQL function]
2827** <li> the [data_version pragma]
2828** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control]
2829** </ul>
2830*/
2831SQLITE_API int sqlite3_total_changes(sqlite3*);
2832SQLITE_API sqlite3_int64 sqlite3_total_changes64(sqlite3*);
2833
2834/*
2835** CAPI3REF: Interrupt A Long-Running Query
2836** METHOD: sqlite3
2837**
2838** ^This function causes any pending database operation to abort and
2839** return at its earliest opportunity. This routine is typically
2840** called in response to a user action such as pressing "Cancel"
2841** or Ctrl-C where the user wants a long query operation to halt
2842** immediately.
2843**
2844** ^It is safe to call this routine from a thread different from the
2845** thread that is currently running the database operation. But it
2846** is not safe to call this routine with a [database connection] that
2847** is closed or might close before sqlite3_interrupt() returns.
2848**
2849** ^If an SQL operation is very nearly finished at the time when
2850** sqlite3_interrupt() is called, then it might not have an opportunity
2851** to be interrupted and might continue to completion.
2852**
2853** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2854** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2855** that is inside an explicit transaction, then the entire transaction
2856** will be rolled back automatically.
2857**
2858** ^The sqlite3_interrupt(D) call is in effect until all currently running
2859** SQL statements on [database connection] D complete. ^Any new SQL statements
2860** that are started after the sqlite3_interrupt() call and before the
2861** running statement count reaches zero are interrupted as if they had been
2862** running prior to the sqlite3_interrupt() call. ^New SQL statements
2863** that are started after the running statement count reaches zero are
2864** not effected by the sqlite3_interrupt().
2865** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2866** SQL statements is a no-op and has no effect on SQL statements
2867** that are started after the sqlite3_interrupt() call returns.
2868**
2869** ^The [sqlite3_is_interrupted(D)] interface can be used to determine whether
2870** or not an interrupt is currently in effect for [database connection] D.
2871** It returns 1 if an interrupt is currently in effect, or 0 otherwise.
2872*/
2873SQLITE_API void sqlite3_interrupt(sqlite3*);
2874SQLITE_API int sqlite3_is_interrupted(sqlite3*);
2875
2876/*
2877** CAPI3REF: Determine If An SQL Statement Is Complete
2878**
2879** These routines are useful during command-line input to determine if the
2880** currently entered text seems to form a complete SQL statement or
2881** if additional input is needed before sending the text into
2882** SQLite for parsing. ^These routines return 1 if the input string
2883** appears to be a complete SQL statement. ^A statement is judged to be
2884** complete if it ends with a semicolon token and is not a prefix of a
2885** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
2886** string literals or quoted identifier names or comments are not
2887** independent tokens (they are part of the token in which they are
2888** embedded) and thus do not count as a statement terminator. ^Whitespace
2889** and comments that follow the final semicolon are ignored.
2890**
2891** ^These routines return 0 if the statement is incomplete. ^If a
2892** memory allocation fails, then SQLITE_NOMEM is returned.
2893**
2894** ^These routines do not parse the SQL statements thus
2895** will not detect syntactically incorrect SQL.
2896**
2897** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2898** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2899** automatically by sqlite3_complete16(). If that initialization fails,
2900** then the return value from sqlite3_complete16() will be non-zero
2901** regardless of whether or not the input SQL is complete.)^
2902**
2903** The input to [sqlite3_complete()] must be a zero-terminated
2904** UTF-8 string.
2905**
2906** The input to [sqlite3_complete16()] must be a zero-terminated
2907** UTF-16 string in native byte order.
2908*/
2909SQLITE_API int sqlite3_complete(const char *sql);
2910SQLITE_API int sqlite3_complete16(const void *sql);
2911
2912/*
2913** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2914** KEYWORDS: {busy-handler callback} {busy handler}
2915** METHOD: sqlite3
2916**
2917** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2918** that might be invoked with argument P whenever
2919** an attempt is made to access a database table associated with
2920** [database connection] D when another thread
2921** or process has the table locked.
2922** The sqlite3_busy_handler() interface is used to implement
2923** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2924**
2925** ^If the busy callback is NULL, then [SQLITE_BUSY]
2926** is returned immediately upon encountering the lock. ^If the busy callback
2927** is not NULL, then the callback might be invoked with two arguments.
2928**
2929** ^The first argument to the busy handler is a copy of the void* pointer which
2930** is the third argument to sqlite3_busy_handler(). ^The second argument to
2931** the busy handler callback is the number of times that the busy handler has
2932** been invoked previously for the same locking event. ^If the
2933** busy callback returns 0, then no additional attempts are made to
2934** access the database and [SQLITE_BUSY] is returned
2935** to the application.
2936** ^If the callback returns non-zero, then another attempt
2937** is made to access the database and the cycle repeats.
2938**
2939** The presence of a busy handler does not guarantee that it will be invoked
2940** when there is lock contention. ^If SQLite determines that invoking the busy
2941** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2942** to the application instead of invoking the
2943** busy handler.
2944** Consider a scenario where one process is holding a read lock that
2945** it is trying to promote to a reserved lock and
2946** a second process is holding a reserved lock that it is trying
2947** to promote to an exclusive lock. The first process cannot proceed
2948** because it is blocked by the second and the second process cannot
2949** proceed because it is blocked by the first. If both processes
2950** invoke the busy handlers, neither will make any progress. Therefore,
2951** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2952** will induce the first process to release its read lock and allow
2953** the second process to proceed.
2954**
2955** ^The default busy callback is NULL.
2956**
2957** ^(There can only be a single busy handler defined for each
2958** [database connection]. Setting a new busy handler clears any
2959** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
2960** or evaluating [PRAGMA busy_timeout=N] will change the
2961** busy handler and thus clear any previously set busy handler.
2962**
2963** The busy callback should not take any actions which modify the
2964** database connection that invoked the busy handler. In other words,
2965** the busy handler is not reentrant. Any such actions
2966** result in undefined behavior.
2967**
2968** A busy handler must not close the database connection
2969** or [prepared statement] that invoked the busy handler.
2970*/
2971SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
2972
2973/*
2974** CAPI3REF: Set A Busy Timeout
2975** METHOD: sqlite3
2976**
2977** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2978** for a specified amount of time when a table is locked. ^The handler
2979** will sleep multiple times until at least "ms" milliseconds of sleeping
2980** have accumulated. ^After at least "ms" milliseconds of sleeping,
2981** the handler returns 0 which causes [sqlite3_step()] to return
2982** [SQLITE_BUSY].
2983**
2984** ^Calling this routine with an argument less than or equal to zero
2985** turns off all busy handlers.
2986**
2987** ^(There can only be a single busy handler for a particular
2988** [database connection] at any given moment. If another busy handler
2989** was defined (using [sqlite3_busy_handler()]) prior to calling
2990** this routine, that other busy handler is cleared.)^
2991**
2992** See also: [PRAGMA busy_timeout]
2993*/
2994SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
2995
2996/*
2997** CAPI3REF: Convenience Routines For Running Queries
2998** METHOD: sqlite3
2999**
3000** This is a legacy interface that is preserved for backwards compatibility.
3001** Use of this interface is not recommended.
3002**
3003** Definition: A <b>result table</b> is memory data structure created by the
3004** [sqlite3_get_table()] interface. A result table records the
3005** complete query results from one or more queries.
3006**
3007** The table conceptually has a number of rows and columns. But
3008** these numbers are not part of the result table itself. These
3009** numbers are obtained separately. Let N be the number of rows
3010** and M be the number of columns.
3011**
3012** A result table is an array of pointers to zero-terminated UTF-8 strings.
3013** There are (N+1)*M elements in the array. The first M pointers point
3014** to zero-terminated strings that contain the names of the columns.
3015** The remaining entries all point to query results. NULL values result
3016** in NULL pointers. All other values are in their UTF-8 zero-terminated
3017** string representation as returned by [sqlite3_column_text()].
3018**
3019** A result table might consist of one or more memory allocations.
3020** It is not safe to pass a result table directly to [sqlite3_free()].
3021** A result table should be deallocated using [sqlite3_free_table()].
3022**
3023** ^(As an example of the result table format, suppose a query result
3024** is as follows:
3025**
3026** <blockquote><pre>
3027** Name | Age
3028** -----------------------
3029** Alice | 43
3030** Bob | 28
3031** Cindy | 21
3032** </pre></blockquote>
3033**
3034** There are two columns (M==2) and three rows (N==3). Thus the
3035** result table has 8 entries. Suppose the result table is stored
3036** in an array named azResult. Then azResult holds this content:
3037**
3038** <blockquote><pre>
3039** azResult&#91;0] = "Name";
3040** azResult&#91;1] = "Age";
3041** azResult&#91;2] = "Alice";
3042** azResult&#91;3] = "43";
3043** azResult&#91;4] = "Bob";
3044** azResult&#91;5] = "28";
3045** azResult&#91;6] = "Cindy";
3046** azResult&#91;7] = "21";
3047** </pre></blockquote>)^
3048**
3049** ^The sqlite3_get_table() function evaluates one or more
3050** semicolon-separated SQL statements in the zero-terminated UTF-8
3051** string of its 2nd parameter and returns a result table to the
3052** pointer given in its 3rd parameter.
3053**
3054** After the application has finished with the result from sqlite3_get_table(),
3055** it must pass the result table pointer to sqlite3_free_table() in order to
3056** release the memory that was malloced. Because of the way the
3057** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
3058** function must not try to call [sqlite3_free()] directly. Only
3059** [sqlite3_free_table()] is able to release the memory properly and safely.
3060**
3061** The sqlite3_get_table() interface is implemented as a wrapper around
3062** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
3063** to any internal data structures of SQLite. It uses only the public
3064** interface defined here. As a consequence, errors that occur in the
3065** wrapper layer outside of the internal [sqlite3_exec()] call are not
3066** reflected in subsequent calls to [sqlite3_errcode()] or
3067** [sqlite3_errmsg()].
3068*/
3069SQLITE_API int sqlite3_get_table(
3070 sqlite3 *db, /* An open database */
3071 const char *zSql, /* SQL to be evaluated */
3072 char ***pazResult, /* Results of the query */
3073 int *pnRow, /* Number of result rows written here */
3074 int *pnColumn, /* Number of result columns written here */
3075 char **pzErrmsg /* Error msg written here */
3076);
3077SQLITE_API void sqlite3_free_table(char **result);
3078
3079/*
3080** CAPI3REF: Formatted String Printing Functions
3081**
3082** These routines are work-alikes of the "printf()" family of functions
3083** from the standard C library.
3084** These routines understand most of the common formatting options from
3085** the standard library printf()
3086** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]).
3087** See the [built-in printf()] documentation for details.
3088**
3089** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
3090** results into memory obtained from [sqlite3_malloc64()].
3091** The strings returned by these two routines should be
3092** released by [sqlite3_free()]. ^Both routines return a
3093** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough
3094** memory to hold the resulting string.
3095**
3096** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
3097** the standard C library. The result is written into the
3098** buffer supplied as the second parameter whose size is given by
3099** the first parameter. Note that the order of the
3100** first two parameters is reversed from snprintf().)^ This is an
3101** historical accident that cannot be fixed without breaking
3102** backwards compatibility. ^(Note also that sqlite3_snprintf()
3103** returns a pointer to its buffer instead of the number of
3104** characters actually written into the buffer.)^ We admit that
3105** the number of characters written would be a more useful return
3106** value but we cannot change the implementation of sqlite3_snprintf()
3107** now without breaking compatibility.
3108**
3109** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
3110** guarantees that the buffer is always zero-terminated. ^The first
3111** parameter "n" is the total size of the buffer, including space for
3112** the zero terminator. So the longest string that can be completely
3113** written will be n-1 characters.
3114**
3115** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
3116**
3117** See also: [built-in printf()], [printf() SQL function]
3118*/
3119SQLITE_API char *sqlite3_mprintf(const char*,...);
3120SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
3121SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
3122SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
3123
3124/*
3125** CAPI3REF: Memory Allocation Subsystem
3126**
3127** The SQLite core uses these three routines for all of its own
3128** internal memory allocation needs. "Core" in the previous sentence
3129** does not include operating-system specific [VFS] implementation. The
3130** Windows VFS uses native malloc() and free() for some operations.
3131**
3132** ^The sqlite3_malloc() routine returns a pointer to a block
3133** of memory at least N bytes in length, where N is the parameter.
3134** ^If sqlite3_malloc() is unable to obtain sufficient free
3135** memory, it returns a NULL pointer. ^If the parameter N to
3136** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
3137** a NULL pointer.
3138**
3139** ^The sqlite3_malloc64(N) routine works just like
3140** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
3141** of a signed 32-bit integer.
3142**
3143** ^Calling sqlite3_free() with a pointer previously returned
3144** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
3145** that it might be reused. ^The sqlite3_free() routine is
3146** a no-op if is called with a NULL pointer. Passing a NULL pointer
3147** to sqlite3_free() is harmless. After being freed, memory
3148** should neither be read nor written. Even reading previously freed
3149** memory might result in a segmentation fault or other severe error.
3150** Memory corruption, a segmentation fault, or other severe error
3151** might result if sqlite3_free() is called with a non-NULL pointer that
3152** was not obtained from sqlite3_malloc() or sqlite3_realloc().
3153**
3154** ^The sqlite3_realloc(X,N) interface attempts to resize a
3155** prior memory allocation X to be at least N bytes.
3156** ^If the X parameter to sqlite3_realloc(X,N)
3157** is a NULL pointer then its behavior is identical to calling
3158** sqlite3_malloc(N).
3159** ^If the N parameter to sqlite3_realloc(X,N) is zero or
3160** negative then the behavior is exactly the same as calling
3161** sqlite3_free(X).
3162** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
3163** of at least N bytes in size or NULL if insufficient memory is available.
3164** ^If M is the size of the prior allocation, then min(N,M) bytes
3165** of the prior allocation are copied into the beginning of buffer returned
3166** by sqlite3_realloc(X,N) and the prior allocation is freed.
3167** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
3168** prior allocation is not freed.
3169**
3170** ^The sqlite3_realloc64(X,N) interfaces works the same as
3171** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
3172** of a 32-bit signed integer.
3173**
3174** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
3175** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
3176** sqlite3_msize(X) returns the size of that memory allocation in bytes.
3177** ^The value returned by sqlite3_msize(X) might be larger than the number
3178** of bytes requested when X was allocated. ^If X is a NULL pointer then
3179** sqlite3_msize(X) returns zero. If X points to something that is not
3180** the beginning of memory allocation, or if it points to a formerly
3181** valid memory allocation that has now been freed, then the behavior
3182** of sqlite3_msize(X) is undefined and possibly harmful.
3183**
3184** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
3185** sqlite3_malloc64(), and sqlite3_realloc64()
3186** is always aligned to at least an 8 byte boundary, or to a
3187** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
3188** option is used.
3189**
3190** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
3191** must be either NULL or else pointers obtained from a prior
3192** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
3193** not yet been released.
3194**
3195** The application must not read or write any part of
3196** a block of memory after it has been released using
3197** [sqlite3_free()] or [sqlite3_realloc()].
3198*/
3199SQLITE_API void *sqlite3_malloc(int);
3200SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
3201SQLITE_API void *sqlite3_realloc(void*, int);
3202SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
3203SQLITE_API void sqlite3_free(void*);
3204SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
3205
3206/*
3207** CAPI3REF: Memory Allocator Statistics
3208**
3209** SQLite provides these two interfaces for reporting on the status
3210** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
3211** routines, which form the built-in memory allocation subsystem.
3212**
3213** ^The [sqlite3_memory_used()] routine returns the number of bytes
3214** of memory currently outstanding (malloced but not freed).
3215** ^The [sqlite3_memory_highwater()] routine returns the maximum
3216** value of [sqlite3_memory_used()] since the high-water mark
3217** was last reset. ^The values returned by [sqlite3_memory_used()] and
3218** [sqlite3_memory_highwater()] include any overhead
3219** added by SQLite in its implementation of [sqlite3_malloc()],
3220** but not overhead added by the any underlying system library
3221** routines that [sqlite3_malloc()] may call.
3222**
3223** ^The memory high-water mark is reset to the current value of
3224** [sqlite3_memory_used()] if and only if the parameter to
3225** [sqlite3_memory_highwater()] is true. ^The value returned
3226** by [sqlite3_memory_highwater(1)] is the high-water mark
3227** prior to the reset.
3228*/
3229SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
3230SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
3231
3232/*
3233** CAPI3REF: Pseudo-Random Number Generator
3234**
3235** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
3236** select random [ROWID | ROWIDs] when inserting new records into a table that
3237** already uses the largest possible [ROWID]. The PRNG is also used for
3238** the built-in random() and randomblob() SQL functions. This interface allows
3239** applications to access the same PRNG for other purposes.
3240**
3241** ^A call to this routine stores N bytes of randomness into buffer P.
3242** ^The P parameter can be a NULL pointer.
3243**
3244** ^If this routine has not been previously called or if the previous
3245** call had N less than one or a NULL pointer for P, then the PRNG is
3246** seeded using randomness obtained from the xRandomness method of
3247** the default [sqlite3_vfs] object.
3248** ^If the previous call to this routine had an N of 1 or more and a
3249** non-NULL P then the pseudo-randomness is generated
3250** internally and without recourse to the [sqlite3_vfs] xRandomness
3251** method.
3252*/
3253SQLITE_API void sqlite3_randomness(int N, void *P);
3254
3255/*
3256** CAPI3REF: Compile-Time Authorization Callbacks
3257** METHOD: sqlite3
3258** KEYWORDS: {authorizer callback}
3259**
3260** ^This routine registers an authorizer callback with a particular
3261** [database connection], supplied in the first argument.
3262** ^The authorizer callback is invoked as SQL statements are being compiled
3263** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
3264** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
3265** and [sqlite3_prepare16_v3()]. ^At various
3266** points during the compilation process, as logic is being created
3267** to perform various actions, the authorizer callback is invoked to
3268** see if those actions are allowed. ^The authorizer callback should
3269** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
3270** specific action but allow the SQL statement to continue to be
3271** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
3272** rejected with an error. ^If the authorizer callback returns
3273** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
3274** then the [sqlite3_prepare_v2()] or equivalent call that triggered
3275** the authorizer will fail with an error message.
3276**
3277** When the callback returns [SQLITE_OK], that means the operation
3278** requested is ok. ^When the callback returns [SQLITE_DENY], the
3279** [sqlite3_prepare_v2()] or equivalent call that triggered the
3280** authorizer will fail with an error message explaining that
3281** access is denied.
3282**
3283** ^The first parameter to the authorizer callback is a copy of the third
3284** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
3285** to the callback is an integer [SQLITE_COPY | action code] that specifies
3286** the particular action to be authorized. ^The third through sixth parameters
3287** to the callback are either NULL pointers or zero-terminated strings
3288** that contain additional details about the action to be authorized.
3289** Applications must always be prepared to encounter a NULL pointer in any
3290** of the third through the sixth parameters of the authorization callback.
3291**
3292** ^If the action code is [SQLITE_READ]
3293** and the callback returns [SQLITE_IGNORE] then the
3294** [prepared statement] statement is constructed to substitute
3295** a NULL value in place of the table column that would have
3296** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
3297** return can be used to deny an untrusted user access to individual
3298** columns of a table.
3299** ^When a table is referenced by a [SELECT] but no column values are
3300** extracted from that table (for example in a query like
3301** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
3302** is invoked once for that table with a column name that is an empty string.
3303** ^If the action code is [SQLITE_DELETE] and the callback returns
3304** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
3305** [truncate optimization] is disabled and all rows are deleted individually.
3306**
3307** An authorizer is used when [sqlite3_prepare | preparing]
3308** SQL statements from an untrusted source, to ensure that the SQL statements
3309** do not try to access data they are not allowed to see, or that they do not
3310** try to execute malicious statements that damage the database. For
3311** example, an application may allow a user to enter arbitrary
3312** SQL queries for evaluation by a database. But the application does
3313** not want the user to be able to make arbitrary changes to the
3314** database. An authorizer could then be put in place while the
3315** user-entered SQL is being [sqlite3_prepare | prepared] that
3316** disallows everything except [SELECT] statements.
3317**
3318** Applications that need to process SQL from untrusted sources
3319** might also consider lowering resource limits using [sqlite3_limit()]
3320** and limiting database size using the [max_page_count] [PRAGMA]
3321** in addition to using an authorizer.
3322**
3323** ^(Only a single authorizer can be in place on a database connection
3324** at a time. Each call to sqlite3_set_authorizer overrides the
3325** previous call.)^ ^Disable the authorizer by installing a NULL callback.
3326** The authorizer is disabled by default.
3327**
3328** The authorizer callback must not do anything that will modify
3329** the database connection that invoked the authorizer callback.
3330** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3331** database connections for the meaning of "modify" in this paragraph.
3332**
3333** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
3334** statement might be re-prepared during [sqlite3_step()] due to a
3335** schema change. Hence, the application should ensure that the
3336** correct authorizer callback remains in place during the [sqlite3_step()].
3337**
3338** ^Note that the authorizer callback is invoked only during
3339** [sqlite3_prepare()] or its variants. Authorization is not
3340** performed during statement evaluation in [sqlite3_step()], unless
3341** as stated in the previous paragraph, sqlite3_step() invokes
3342** sqlite3_prepare_v2() to reprepare a statement after a schema change.
3343*/
3344SQLITE_API int sqlite3_set_authorizer(
3345 sqlite3*,
3346 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
3347 void *pUserData
3348);
3349
3350/*
3351** CAPI3REF: Authorizer Return Codes
3352**
3353** The [sqlite3_set_authorizer | authorizer callback function] must
3354** return either [SQLITE_OK] or one of these two constants in order
3355** to signal SQLite whether or not the action is permitted. See the
3356** [sqlite3_set_authorizer | authorizer documentation] for additional
3357** information.
3358**
3359** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
3360** returned from the [sqlite3_vtab_on_conflict()] interface.
3361*/
3362#define SQLITE_DENY 1 /* Abort the SQL statement with an error */
3363#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
3364
3365/*
3366** CAPI3REF: Authorizer Action Codes
3367**
3368** The [sqlite3_set_authorizer()] interface registers a callback function
3369** that is invoked to authorize certain SQL statement actions. The
3370** second parameter to the callback is an integer code that specifies
3371** what action is being authorized. These are the integer action codes that
3372** the authorizer callback may be passed.
3373**
3374** These action code values signify what kind of operation is to be
3375** authorized. The 3rd and 4th parameters to the authorization
3376** callback function will be parameters or NULL depending on which of these
3377** codes is used as the second parameter. ^(The 5th parameter to the
3378** authorizer callback is the name of the database ("main", "temp",
3379** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
3380** is the name of the inner-most trigger or view that is responsible for
3381** the access attempt or NULL if this access attempt is directly from
3382** top-level SQL code.
3383*/
3384/******************************************* 3rd ************ 4th ***********/
3385#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
3386#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
3387#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
3388#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
3389#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
3390#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
3391#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
3392#define SQLITE_CREATE_VIEW 8 /* View Name NULL */
3393#define SQLITE_DELETE 9 /* Table Name NULL */
3394#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
3395#define SQLITE_DROP_TABLE 11 /* Table Name NULL */
3396#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
3397#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
3398#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
3399#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
3400#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
3401#define SQLITE_DROP_VIEW 17 /* View Name NULL */
3402#define SQLITE_INSERT 18 /* Table Name NULL */
3403#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
3404#define SQLITE_READ 20 /* Table Name Column Name */
3405#define SQLITE_SELECT 21 /* NULL NULL */
3406#define SQLITE_TRANSACTION 22 /* Operation NULL */
3407#define SQLITE_UPDATE 23 /* Table Name Column Name */
3408#define SQLITE_ATTACH 24 /* Filename NULL */
3409#define SQLITE_DETACH 25 /* Database Name NULL */
3410#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
3411#define SQLITE_REINDEX 27 /* Index Name NULL */
3412#define SQLITE_ANALYZE 28 /* Table Name NULL */
3413#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
3414#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
3415#define SQLITE_FUNCTION 31 /* NULL Function Name */
3416#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
3417#define SQLITE_COPY 0 /* No longer used */
3418#define SQLITE_RECURSIVE 33 /* NULL NULL */
3419
3420/*
3421** CAPI3REF: Deprecated Tracing And Profiling Functions
3422** DEPRECATED
3423**
3424** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
3425** instead of the routines described here.
3426**
3427** These routines register callback functions that can be used for
3428** tracing and profiling the execution of SQL statements.
3429**
3430** ^The callback function registered by sqlite3_trace() is invoked at
3431** various times when an SQL statement is being run by [sqlite3_step()].
3432** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
3433** SQL statement text as the statement first begins executing.
3434** ^(Additional sqlite3_trace() callbacks might occur
3435** as each triggered subprogram is entered. The callbacks for triggers
3436** contain a UTF-8 SQL comment that identifies the trigger.)^
3437**
3438** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
3439** the length of [bound parameter] expansion in the output of sqlite3_trace().
3440**
3441** ^The callback function registered by sqlite3_profile() is invoked
3442** as each SQL statement finishes. ^The profile callback contains
3443** the original statement text and an estimate of wall-clock time
3444** of how long that statement took to run. ^The profile callback
3445** time is in units of nanoseconds, however the current implementation
3446** is only capable of millisecond resolution so the six least significant
3447** digits in the time are meaningless. Future versions of SQLite
3448** might provide greater resolution on the profiler callback. Invoking
3449** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the
3450** profile callback.
3451*/
3452SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
3453 void(*xTrace)(void*,const char*), void*);
3454SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
3455 void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
3456
3457/*
3458** CAPI3REF: SQL Trace Event Codes
3459** KEYWORDS: SQLITE_TRACE
3460**
3461** These constants identify classes of events that can be monitored
3462** using the [sqlite3_trace_v2()] tracing logic. The M argument
3463** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
3464** the following constants. ^The first argument to the trace callback
3465** is one of the following constants.
3466**
3467** New tracing constants may be added in future releases.
3468**
3469** ^A trace callback has four arguments: xCallback(T,C,P,X).
3470** ^The T argument is one of the integer type codes above.
3471** ^The C argument is a copy of the context pointer passed in as the
3472** fourth argument to [sqlite3_trace_v2()].
3473** The P and X arguments are pointers whose meanings depend on T.
3474**
3475** <dl>
3476** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
3477** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
3478** first begins running and possibly at other times during the
3479** execution of the prepared statement, such as at the start of each
3480** trigger subprogram. ^The P argument is a pointer to the
3481** [prepared statement]. ^The X argument is a pointer to a string which
3482** is the unexpanded SQL text of the prepared statement or an SQL comment
3483** that indicates the invocation of a trigger. ^The callback can compute
3484** the same text that would have been returned by the legacy [sqlite3_trace()]
3485** interface by using the X argument when X begins with "--" and invoking
3486** [sqlite3_expanded_sql(P)] otherwise.
3487**
3488** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
3489** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
3490** information as is provided by the [sqlite3_profile()] callback.
3491** ^The P argument is a pointer to the [prepared statement] and the
3492** X argument points to a 64-bit integer which is approximately
3493** the number of nanoseconds that the prepared statement took to run.
3494** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
3495**
3496** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
3497** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
3498** statement generates a single row of result.
3499** ^The P argument is a pointer to the [prepared statement] and the
3500** X argument is unused.
3501**
3502** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
3503** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
3504** connection closes.
3505** ^The P argument is a pointer to the [database connection] object
3506** and the X argument is unused.
3507** </dl>
3508*/
3509#define SQLITE_TRACE_STMT 0x01
3510#define SQLITE_TRACE_PROFILE 0x02
3511#define SQLITE_TRACE_ROW 0x04
3512#define SQLITE_TRACE_CLOSE 0x08
3513
3514/*
3515** CAPI3REF: SQL Trace Hook
3516** METHOD: sqlite3
3517**
3518** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
3519** function X against [database connection] D, using property mask M
3520** and context pointer P. ^If the X callback is
3521** NULL or if the M mask is zero, then tracing is disabled. The
3522** M argument should be the bitwise OR-ed combination of
3523** zero or more [SQLITE_TRACE] constants.
3524**
3525** ^Each call to either sqlite3_trace(D,X,P) or sqlite3_trace_v2(D,M,X,P)
3526** overrides (cancels) all prior calls to sqlite3_trace(D,X,P) or
3527** sqlite3_trace_v2(D,M,X,P) for the [database connection] D. Each
3528** database connection may have at most one trace callback.
3529**
3530** ^The X callback is invoked whenever any of the events identified by
3531** mask M occur. ^The integer return value from the callback is currently
3532** ignored, though this may change in future releases. Callback
3533** implementations should return zero to ensure future compatibility.
3534**
3535** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
3536** ^The T argument is one of the [SQLITE_TRACE]
3537** constants to indicate why the callback was invoked.
3538** ^The C argument is a copy of the context pointer.
3539** The P and X arguments are pointers whose meanings depend on T.
3540**
3541** The sqlite3_trace_v2() interface is intended to replace the legacy
3542** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
3543** are deprecated.
3544*/
3545SQLITE_API int sqlite3_trace_v2(
3546 sqlite3*,
3547 unsigned uMask,
3548 int(*xCallback)(unsigned,void*,void*,void*),
3549 void *pCtx
3550);
3551
3552/*
3553** CAPI3REF: Query Progress Callbacks
3554** METHOD: sqlite3
3555**
3556** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
3557** function X to be invoked periodically during long running calls to
3558** [sqlite3_step()] and [sqlite3_prepare()] and similar for
3559** database connection D. An example use for this
3560** interface is to keep a GUI updated during a large query.
3561**
3562** ^The parameter P is passed through as the only parameter to the
3563** callback function X. ^The parameter N is the approximate number of
3564** [virtual machine instructions] that are evaluated between successive
3565** invocations of the callback X. ^If N is less than one then the progress
3566** handler is disabled.
3567**
3568** ^Only a single progress handler may be defined at one time per
3569** [database connection]; setting a new progress handler cancels the
3570** old one. ^Setting parameter X to NULL disables the progress handler.
3571** ^The progress handler is also disabled by setting N to a value less
3572** than 1.
3573**
3574** ^If the progress callback returns non-zero, the operation is
3575** interrupted. This feature can be used to implement a
3576** "Cancel" button on a GUI progress dialog box.
3577**
3578** The progress handler callback must not do anything that will modify
3579** the database connection that invoked the progress handler.
3580** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3581** database connections for the meaning of "modify" in this paragraph.
3582**
3583** The progress handler callback would originally only be invoked from the
3584** bytecode engine. It still might be invoked during [sqlite3_prepare()]
3585** and similar because those routines might force a reparse of the schema
3586** which involves running the bytecode engine. However, beginning with
3587** SQLite version 3.41.0, the progress handler callback might also be
3588** invoked directly from [sqlite3_prepare()] while analyzing and generating
3589** code for complex queries.
3590*/
3591SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
3592
3593/*
3594** CAPI3REF: Opening A New Database Connection
3595** CONSTRUCTOR: sqlite3
3596**
3597** ^These routines open an SQLite database file as specified by the
3598** filename argument. ^The filename argument is interpreted as UTF-8 for
3599** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
3600** order for sqlite3_open16(). ^(A [database connection] handle is usually
3601** returned in *ppDb, even if an error occurs. The only exception is that
3602** if SQLite is unable to allocate memory to hold the [sqlite3] object,
3603** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
3604** object.)^ ^(If the database is opened (and/or created) successfully, then
3605** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
3606** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
3607** an English language description of the error following a failure of any
3608** of the sqlite3_open() routines.
3609**
3610** ^The default encoding will be UTF-8 for databases created using
3611** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases
3612** created using sqlite3_open16() will be UTF-16 in the native byte order.
3613**
3614** Whether or not an error occurs when it is opened, resources
3615** associated with the [database connection] handle should be released by
3616** passing it to [sqlite3_close()] when it is no longer required.
3617**
3618** The sqlite3_open_v2() interface works like sqlite3_open()
3619** except that it accepts two additional parameters for additional control
3620** over the new database connection. ^(The flags parameter to
3621** sqlite3_open_v2() must include, at a minimum, one of the following
3622** three flag combinations:)^
3623**
3624** <dl>
3625** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
3626** <dd>The database is opened in read-only mode. If the database does
3627** not already exist, an error is returned.</dd>)^
3628**
3629** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
3630** <dd>The database is opened for reading and writing if possible, or
3631** reading only if the file is write protected by the operating
3632** system. In either case the database must already exist, otherwise
3633** an error is returned. For historical reasons, if opening in
3634** read-write mode fails due to OS-level permissions, an attempt is
3635** made to open it in read-only mode. [sqlite3_db_readonly()] can be
3636** used to determine whether the database is actually
3637** read-write.</dd>)^
3638**
3639** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
3640** <dd>The database is opened for reading and writing, and is created if
3641** it does not already exist. This is the behavior that is always used for
3642** sqlite3_open() and sqlite3_open16().</dd>)^
3643** </dl>
3644**
3645** In addition to the required flags, the following optional flags are
3646** also supported:
3647**
3648** <dl>
3649** ^(<dt>[SQLITE_OPEN_URI]</dt>
3650** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^
3651**
3652** ^(<dt>[SQLITE_OPEN_MEMORY]</dt>
3653** <dd>The database will be opened as an in-memory database. The database
3654** is named by the "filename" argument for the purposes of cache-sharing,
3655** if shared cache mode is enabled, but the "filename" is otherwise ignored.
3656** </dd>)^
3657**
3658** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt>
3659** <dd>The new database connection will use the "multi-thread"
3660** [threading mode].)^ This means that separate threads are allowed
3661** to use SQLite at the same time, as long as each thread is using
3662** a different [database connection].
3663**
3664** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt>
3665** <dd>The new database connection will use the "serialized"
3666** [threading mode].)^ This means the multiple threads can safely
3667** attempt to use the same database connection at the same time.
3668** (Mutexes will block any actual concurrency, but in this mode
3669** there is no harm in trying.)
3670**
3671** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt>
3672** <dd>The database is opened [shared cache] enabled, overriding
3673** the default shared cache setting provided by
3674** [sqlite3_enable_shared_cache()].)^
3675** The [use of shared cache mode is discouraged] and hence shared cache
3676** capabilities may be omitted from many builds of SQLite. In such cases,
3677** this option is a no-op.
3678**
3679** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt>
3680** <dd>The database is opened [shared cache] disabled, overriding
3681** the default shared cache setting provided by
3682** [sqlite3_enable_shared_cache()].)^
3683**
3684** [[OPEN_EXRESCODE]] ^(<dt>[SQLITE_OPEN_EXRESCODE]</dt>
3685** <dd>The database connection comes up in "extended result code mode".
3686** In other words, the database behaves as if
3687** [sqlite3_extended_result_codes(db,1)] were called on the database
3688** connection as soon as the connection is created. In addition to setting
3689** the extended result code mode, this flag also causes [sqlite3_open_v2()]
3690** to return an extended result code.</dd>
3691**
3692** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt>
3693** <dd>The database filename is not allowed to contain a symbolic link</dd>
3694** </dl>)^
3695**
3696** If the 3rd parameter to sqlite3_open_v2() is not one of the
3697** required combinations shown above optionally combined with other
3698** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
3699** then the behavior is undefined. Historic versions of SQLite
3700** have silently ignored surplus bits in the flags parameter to
3701** sqlite3_open_v2(), however that behavior might not be carried through
3702** into future versions of SQLite and so applications should not rely
3703** upon it. Note in particular that the SQLITE_OPEN_EXCLUSIVE flag is a no-op
3704** for sqlite3_open_v2(). The SQLITE_OPEN_EXCLUSIVE does *not* cause
3705** the open to fail if the database already exists. The SQLITE_OPEN_EXCLUSIVE
3706** flag is intended for use by the [sqlite3_vfs|VFS interface] only, and not
3707** by sqlite3_open_v2().
3708**
3709** ^The fourth parameter to sqlite3_open_v2() is the name of the
3710** [sqlite3_vfs] object that defines the operating system interface that
3711** the new database connection should use. ^If the fourth parameter is
3712** a NULL pointer then the default [sqlite3_vfs] object is used.
3713**
3714** ^If the filename is ":memory:", then a private, temporary in-memory database
3715** is created for the connection. ^This in-memory database will vanish when
3716** the database connection is closed. Future versions of SQLite might
3717** make use of additional special filenames that begin with the ":" character.
3718** It is recommended that when a database filename actually does begin with
3719** a ":" character you should prefix the filename with a pathname such as
3720** "./" to avoid ambiguity.
3721**
3722** ^If the filename is an empty string, then a private, temporary
3723** on-disk database will be created. ^This private database will be
3724** automatically deleted as soon as the database connection is closed.
3725**
3726** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
3727**
3728** ^If [URI filename] interpretation is enabled, and the filename argument
3729** begins with "file:", then the filename is interpreted as a URI. ^URI
3730** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
3731** set in the third argument to sqlite3_open_v2(), or if it has
3732** been enabled globally using the [SQLITE_CONFIG_URI] option with the
3733** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
3734** URI filename interpretation is turned off
3735** by default, but future releases of SQLite might enable URI filename
3736** interpretation by default. See "[URI filenames]" for additional
3737** information.
3738**
3739** URI filenames are parsed according to RFC 3986. ^If the URI contains an
3740** authority, then it must be either an empty string or the string
3741** "localhost". ^If the authority is not an empty string or "localhost", an
3742** error is returned to the caller. ^The fragment component of a URI, if
3743** present, is ignored.
3744**
3745** ^SQLite uses the path component of the URI as the name of the disk file
3746** which contains the database. ^If the path begins with a '/' character,
3747** then it is interpreted as an absolute path. ^If the path does not begin
3748** with a '/' (meaning that the authority section is omitted from the URI)
3749** then the path is interpreted as a relative path.
3750** ^(On windows, the first component of an absolute path
3751** is a drive specification (e.g. "C:").)^
3752**
3753** [[core URI query parameters]]
3754** The query component of a URI may contain parameters that are interpreted
3755** either by SQLite itself, or by a [VFS | custom VFS implementation].
3756** SQLite and its built-in [VFSes] interpret the
3757** following query parameters:
3758**
3759** <ul>
3760** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
3761** a VFS object that provides the operating system interface that should
3762** be used to access the database file on disk. ^If this option is set to
3763** an empty string the default VFS object is used. ^Specifying an unknown
3764** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
3765** present, then the VFS specified by the option takes precedence over
3766** the value passed as the fourth parameter to sqlite3_open_v2().
3767**
3768** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
3769** "rwc", or "memory". Attempting to set it to any other value is
3770** an error)^.
3771** ^If "ro" is specified, then the database is opened for read-only
3772** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
3773** third argument to sqlite3_open_v2(). ^If the mode option is set to
3774** "rw", then the database is opened for read-write (but not create)
3775** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
3776** been set. ^Value "rwc" is equivalent to setting both
3777** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is
3778** set to "memory" then a pure [in-memory database] that never reads
3779** or writes from disk is used. ^It is an error to specify a value for
3780** the mode parameter that is less restrictive than that specified by
3781** the flags passed in the third parameter to sqlite3_open_v2().
3782**
3783** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
3784** "private". ^Setting it to "shared" is equivalent to setting the
3785** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
3786** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
3787** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
3788** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
3789** a URI filename, its value overrides any behavior requested by setting
3790** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
3791**
3792** <li> <b>psow</b>: ^The psow parameter indicates whether or not the
3793** [powersafe overwrite] property does or does not apply to the
3794** storage media on which the database file resides.
3795**
3796** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
3797** which if set disables file locking in rollback journal modes. This
3798** is useful for accessing a database on a filesystem that does not
3799** support locking. Caution: Database corruption might result if two
3800** or more processes write to the same database and any one of those
3801** processes uses nolock=1.
3802**
3803** <li> <b>immutable</b>: ^The immutable parameter is a boolean query
3804** parameter that indicates that the database file is stored on
3805** read-only media. ^When immutable is set, SQLite assumes that the
3806** database file cannot be changed, even by a process with higher
3807** privilege, and so the database is opened read-only and all locking
3808** and change detection is disabled. Caution: Setting the immutable
3809** property on a database file that does in fact change can result
3810** in incorrect query results and/or [SQLITE_CORRUPT] errors.
3811** See also: [SQLITE_IOCAP_IMMUTABLE].
3812**
3813** </ul>
3814**
3815** ^Specifying an unknown parameter in the query component of a URI is not an
3816** error. Future versions of SQLite might understand additional query
3817** parameters. See "[query parameters with special meaning to SQLite]" for
3818** additional information.
3819**
3820** [[URI filename examples]] <h3>URI filename examples</h3>
3821**
3822** <table border="1" align=center cellpadding=5>
3823** <tr><th> URI filenames <th> Results
3824** <tr><td> file:data.db <td>
3825** Open the file "data.db" in the current directory.
3826** <tr><td> file:/home/fred/data.db<br>
3827** file:///home/fred/data.db <br>
3828** file://localhost/home/fred/data.db <br> <td>
3829** Open the database file "/home/fred/data.db".
3830** <tr><td> file://darkstar/home/fred/data.db <td>
3831** An error. "darkstar" is not a recognized authority.
3832** <tr><td style="white-space:nowrap">
3833** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
3834** <td> Windows only: Open the file "data.db" on fred's desktop on drive
3835** C:. Note that the %20 escaping in this example is not strictly
3836** necessary - space characters can be used literally
3837** in URI filenames.
3838** <tr><td> file:data.db?mode=ro&cache=private <td>
3839** Open file "data.db" in the current directory for read-only access.
3840** Regardless of whether or not shared-cache mode is enabled by
3841** default, use a private cache.
3842** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
3843** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
3844** that uses dot-files in place of posix advisory locking.
3845** <tr><td> file:data.db?mode=readonly <td>
3846** An error. "readonly" is not a valid option for the "mode" parameter.
3847** Use "ro" instead: "file:data.db?mode=ro".
3848** </table>
3849**
3850** ^URI hexadecimal escape sequences (%HH) are supported within the path and
3851** query components of a URI. A hexadecimal escape sequence consists of a
3852** percent sign - "%" - followed by exactly two hexadecimal digits
3853** specifying an octet value. ^Before the path or query components of a
3854** URI filename are interpreted, they are encoded using UTF-8 and all
3855** hexadecimal escape sequences replaced by a single byte containing the
3856** corresponding octet. If this process generates an invalid UTF-8 encoding,
3857** the results are undefined.
3858**
3859** <b>Note to Windows users:</b> The encoding used for the filename argument
3860** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
3861** codepage is currently defined. Filenames containing international
3862** characters must be converted to UTF-8 prior to passing them into
3863** sqlite3_open() or sqlite3_open_v2().
3864**
3865** <b>Note to Windows Runtime users:</b> The temporary directory must be set
3866** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
3867** features that require the use of temporary files may fail.
3868**
3869** See also: [sqlite3_temp_directory]
3870*/
3871SQLITE_API int sqlite3_open(
3872 const char *filename, /* Database filename (UTF-8) */
3873 sqlite3 **ppDb /* OUT: SQLite db handle */
3874);
3875SQLITE_API int sqlite3_open16(
3876 const void *filename, /* Database filename (UTF-16) */
3877 sqlite3 **ppDb /* OUT: SQLite db handle */
3878);
3879SQLITE_API int sqlite3_open_v2(
3880 const char *filename, /* Database filename (UTF-8) */
3881 sqlite3 **ppDb, /* OUT: SQLite db handle */
3882 int flags, /* Flags */
3883 const char *zVfs /* Name of VFS module to use */
3884);
3885
3886/*
3887** CAPI3REF: Obtain Values For URI Parameters
3888**
3889** These are utility routines, useful to [VFS|custom VFS implementations],
3890** that check if a database file was a URI that contained a specific query
3891** parameter, and if so obtains the value of that query parameter.
3892**
3893** The first parameter to these interfaces (hereafter referred to
3894** as F) must be one of:
3895** <ul>
3896** <li> A database filename pointer created by the SQLite core and
3897** passed into the xOpen() method of a VFS implementation, or
3898** <li> A filename obtained from [sqlite3_db_filename()], or
3899** <li> A new filename constructed using [sqlite3_create_filename()].
3900** </ul>
3901** If the F parameter is not one of the above, then the behavior is
3902** undefined and probably undesirable. Older versions of SQLite were
3903** more tolerant of invalid F parameters than newer versions.
3904**
3905** If F is a suitable filename (as described in the previous paragraph)
3906** and if P is the name of the query parameter, then
3907** sqlite3_uri_parameter(F,P) returns the value of the P
3908** parameter if it exists or a NULL pointer if P does not appear as a
3909** query parameter on F. If P is a query parameter of F and it
3910** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3911** a pointer to an empty string.
3912**
3913** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3914** parameter and returns true (1) or false (0) according to the value
3915** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3916** value of query parameter P is one of "yes", "true", or "on" in any
3917** case or if the value begins with a non-zero number. The
3918** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3919** query parameter P is one of "no", "false", or "off" in any case or
3920** if the value begins with a numeric zero. If P is not a query
3921** parameter on F or if the value of P does not match any of the
3922** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3923**
3924** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3925** 64-bit signed integer and returns that integer, or D if P does not
3926** exist. If the value of P is something other than an integer, then
3927** zero is returned.
3928**
3929** The sqlite3_uri_key(F,N) returns a pointer to the name (not
3930** the value) of the N-th query parameter for filename F, or a NULL
3931** pointer if N is less than zero or greater than the number of query
3932** parameters minus 1. The N value is zero-based so N should be 0 to obtain
3933** the name of the first query parameter, 1 for the second parameter, and
3934** so forth.
3935**
3936** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3937** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
3938** is not a database file pathname pointer that the SQLite core passed
3939** into the xOpen VFS method, then the behavior of this routine is undefined
3940** and probably undesirable.
3941**
3942** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F
3943** parameter can also be the name of a rollback journal file or WAL file
3944** in addition to the main database file. Prior to version 3.31.0, these
3945** routines would only work if F was the name of the main database file.
3946** When the F parameter is the name of the rollback journal or WAL file,
3947** it has access to all the same query parameters as were found on the
3948** main database file.
3949**
3950** See the [URI filename] documentation for additional information.
3951*/
3952SQLITE_API const char *sqlite3_uri_parameter(sqlite3_filename z, const char *zParam);
3953SQLITE_API int sqlite3_uri_boolean(sqlite3_filename z, const char *zParam, int bDefault);
3954SQLITE_API sqlite3_int64 sqlite3_uri_int64(sqlite3_filename, const char*, sqlite3_int64);
3955SQLITE_API const char *sqlite3_uri_key(sqlite3_filename z, int N);
3956
3957/*
3958** CAPI3REF: Translate filenames
3959**
3960** These routines are available to [VFS|custom VFS implementations] for
3961** translating filenames between the main database file, the journal file,
3962** and the WAL file.
3963**
3964** If F is the name of an sqlite database file, journal file, or WAL file
3965** passed by the SQLite core into the VFS, then sqlite3_filename_database(F)
3966** returns the name of the corresponding database file.
3967**
3968** If F is the name of an sqlite database file, journal file, or WAL file
3969** passed by the SQLite core into the VFS, or if F is a database filename
3970** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F)
3971** returns the name of the corresponding rollback journal file.
3972**
3973** If F is the name of an sqlite database file, journal file, or WAL file
3974** that was passed by the SQLite core into the VFS, or if F is a database
3975** filename obtained from [sqlite3_db_filename()], then
3976** sqlite3_filename_wal(F) returns the name of the corresponding
3977** WAL file.
3978**
3979** In all of the above, if F is not the name of a database, journal or WAL
3980** filename passed into the VFS from the SQLite core and F is not the
3981** return value from [sqlite3_db_filename()], then the result is
3982** undefined and is likely a memory access violation.
3983*/
3984SQLITE_API const char *sqlite3_filename_database(sqlite3_filename);
3985SQLITE_API const char *sqlite3_filename_journal(sqlite3_filename);
3986SQLITE_API const char *sqlite3_filename_wal(sqlite3_filename);
3987
3988/*
3989** CAPI3REF: Database File Corresponding To A Journal
3990**
3991** ^If X is the name of a rollback or WAL-mode journal file that is
3992** passed into the xOpen method of [sqlite3_vfs], then
3993** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file]
3994** object that represents the main database file.
3995**
3996** This routine is intended for use in custom [VFS] implementations
3997** only. It is not a general-purpose interface.
3998** The argument sqlite3_file_object(X) must be a filename pointer that
3999** has been passed into [sqlite3_vfs].xOpen method where the
4000** flags parameter to xOpen contains one of the bits
4001** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL]. Any other use
4002** of this routine results in undefined and probably undesirable
4003** behavior.
4004*/
4005SQLITE_API sqlite3_file *sqlite3_database_file_object(const char*);
4006
4007/*
4008** CAPI3REF: Create and Destroy VFS Filenames
4009**
4010** These interfaces are provided for use by [VFS shim] implementations and
4011** are not useful outside of that context.
4012**
4013** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of
4014** database filename D with corresponding journal file J and WAL file W and
4015** with N URI parameters key/values pairs in the array P. The result from
4016** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that
4017** is safe to pass to routines like:
4018** <ul>
4019** <li> [sqlite3_uri_parameter()],
4020** <li> [sqlite3_uri_boolean()],
4021** <li> [sqlite3_uri_int64()],
4022** <li> [sqlite3_uri_key()],
4023** <li> [sqlite3_filename_database()],
4024** <li> [sqlite3_filename_journal()], or
4025** <li> [sqlite3_filename_wal()].
4026** </ul>
4027** If a memory allocation error occurs, sqlite3_create_filename() might
4028** return a NULL pointer. The memory obtained from sqlite3_create_filename(X)
4029** must be released by a corresponding call to sqlite3_free_filename(Y).
4030**
4031** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array
4032** of 2*N pointers to strings. Each pair of pointers in this array corresponds
4033** to a key and value for a query parameter. The P parameter may be a NULL
4034** pointer if N is zero. None of the 2*N pointers in the P array may be
4035** NULL pointers and key pointers should not be empty strings.
4036** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may
4037** be NULL pointers, though they can be empty strings.
4038**
4039** The sqlite3_free_filename(Y) routine releases a memory allocation
4040** previously obtained from sqlite3_create_filename(). Invoking
4041** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op.
4042**
4043** If the Y parameter to sqlite3_free_filename(Y) is anything other
4044** than a NULL pointer or a pointer previously acquired from
4045** sqlite3_create_filename(), then bad things such as heap
4046** corruption or segfaults may occur. The value Y should not be
4047** used again after sqlite3_free_filename(Y) has been called. This means
4048** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y,
4049** then the corresponding [sqlite3_module.xClose() method should also be
4050** invoked prior to calling sqlite3_free_filename(Y).
4051*/
4052SQLITE_API sqlite3_filename sqlite3_create_filename(
4053 const char *zDatabase,
4054 const char *zJournal,
4055 const char *zWal,
4056 int nParam,
4057 const char **azParam
4058);
4059SQLITE_API void sqlite3_free_filename(sqlite3_filename);
4060
4061/*
4062** CAPI3REF: Error Codes And Messages
4063** METHOD: sqlite3
4064**
4065** ^If the most recent sqlite3_* API call associated with
4066** [database connection] D failed, then the sqlite3_errcode(D) interface
4067** returns the numeric [result code] or [extended result code] for that
4068** API call.
4069** ^The sqlite3_extended_errcode()
4070** interface is the same except that it always returns the
4071** [extended result code] even when extended result codes are
4072** disabled.
4073**
4074** The values returned by sqlite3_errcode() and/or
4075** sqlite3_extended_errcode() might change with each API call.
4076** Except, there are some interfaces that are guaranteed to never
4077** change the value of the error code. The error-code preserving
4078** interfaces include the following:
4079**
4080** <ul>
4081** <li> sqlite3_errcode()
4082** <li> sqlite3_extended_errcode()
4083** <li> sqlite3_errmsg()
4084** <li> sqlite3_errmsg16()
4085** <li> sqlite3_error_offset()
4086** </ul>
4087**
4088** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
4089** text that describes the error, as either UTF-8 or UTF-16 respectively,
4090** or NULL if no error message is available.
4091** (See how SQLite handles [invalid UTF] for exceptions to this rule.)
4092** ^(Memory to hold the error message string is managed internally.
4093** The application does not need to worry about freeing the result.
4094** However, the error string might be overwritten or deallocated by
4095** subsequent calls to other SQLite interface functions.)^
4096**
4097** ^The sqlite3_errstr(E) interface returns the English-language text
4098** that describes the [result code] E, as UTF-8, or NULL if E is not an
4099** result code for which a text error message is available.
4100** ^(Memory to hold the error message string is managed internally
4101** and must not be freed by the application)^.
4102**
4103** ^If the most recent error references a specific token in the input
4104** SQL, the sqlite3_error_offset() interface returns the byte offset
4105** of the start of that token. ^The byte offset returned by
4106** sqlite3_error_offset() assumes that the input SQL is UTF8.
4107** ^If the most recent error does not reference a specific token in the input
4108** SQL, then the sqlite3_error_offset() function returns -1.
4109**
4110** When the serialized [threading mode] is in use, it might be the
4111** case that a second error occurs on a separate thread in between
4112** the time of the first error and the call to these interfaces.
4113** When that happens, the second error will be reported since these
4114** interfaces always report the most recent result. To avoid
4115** this, each thread can obtain exclusive use of the [database connection] D
4116** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
4117** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
4118** all calls to the interfaces listed here are completed.
4119**
4120** If an interface fails with SQLITE_MISUSE, that means the interface
4121** was invoked incorrectly by the application. In that case, the
4122** error code and message may or may not be set.
4123*/
4124SQLITE_API int sqlite3_errcode(sqlite3 *db);
4125SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
4126SQLITE_API const char *sqlite3_errmsg(sqlite3*);
4127SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
4128SQLITE_API const char *sqlite3_errstr(int);
4129SQLITE_API int sqlite3_error_offset(sqlite3 *db);
4130
4131/*
4132** CAPI3REF: Prepared Statement Object
4133** KEYWORDS: {prepared statement} {prepared statements}
4134**
4135** An instance of this object represents a single SQL statement that
4136** has been compiled into binary form and is ready to be evaluated.
4137**
4138** Think of each SQL statement as a separate computer program. The
4139** original SQL text is source code. A prepared statement object
4140** is the compiled object code. All SQL must be converted into a
4141** prepared statement before it can be run.
4142**
4143** The life-cycle of a prepared statement object usually goes like this:
4144**
4145** <ol>
4146** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
4147** <li> Bind values to [parameters] using the sqlite3_bind_*()
4148** interfaces.
4149** <li> Run the SQL by calling [sqlite3_step()] one or more times.
4150** <li> Reset the prepared statement using [sqlite3_reset()] then go back
4151** to step 2. Do this zero or more times.
4152** <li> Destroy the object using [sqlite3_finalize()].
4153** </ol>
4154*/
4155typedef struct sqlite3_stmt sqlite3_stmt;
4156
4157/*
4158** CAPI3REF: Run-time Limits
4159** METHOD: sqlite3
4160**
4161** ^(This interface allows the size of various constructs to be limited
4162** on a connection by connection basis. The first parameter is the
4163** [database connection] whose limit is to be set or queried. The
4164** second parameter is one of the [limit categories] that define a
4165** class of constructs to be size limited. The third parameter is the
4166** new limit for that construct.)^
4167**
4168** ^If the new limit is a negative number, the limit is unchanged.
4169** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
4170** [limits | hard upper bound]
4171** set at compile-time by a C preprocessor macro called
4172** [limits | SQLITE_MAX_<i>NAME</i>].
4173** (The "_LIMIT_" in the name is changed to "_MAX_".))^
4174** ^Attempts to increase a limit above its hard upper bound are
4175** silently truncated to the hard upper bound.
4176**
4177** ^Regardless of whether or not the limit was changed, the
4178** [sqlite3_limit()] interface returns the prior value of the limit.
4179** ^Hence, to find the current value of a limit without changing it,
4180** simply invoke this interface with the third parameter set to -1.
4181**
4182** Run-time limits are intended for use in applications that manage
4183** both their own internal database and also databases that are controlled
4184** by untrusted external sources. An example application might be a
4185** web browser that has its own databases for storing history and
4186** separate databases controlled by JavaScript applications downloaded
4187** off the Internet. The internal databases can be given the
4188** large, default limits. Databases managed by external sources can
4189** be given much smaller limits designed to prevent a denial of service
4190** attack. Developers might also want to use the [sqlite3_set_authorizer()]
4191** interface to further control untrusted SQL. The size of the database
4192** created by an untrusted script can be contained using the
4193** [max_page_count] [PRAGMA].
4194**
4195** New run-time limit categories may be added in future releases.
4196*/
4197SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
4198
4199/*
4200** CAPI3REF: Run-Time Limit Categories
4201** KEYWORDS: {limit category} {*limit categories}
4202**
4203** These constants define various performance limits
4204** that can be lowered at run-time using [sqlite3_limit()].
4205** The synopsis of the meanings of the various limits is shown below.
4206** Additional information is available at [limits | Limits in SQLite].
4207**
4208** <dl>
4209** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
4210** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
4211**
4212** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
4213** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
4214**
4215** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
4216** <dd>The maximum number of columns in a table definition or in the
4217** result set of a [SELECT] or the maximum number of columns in an index
4218** or in an ORDER BY or GROUP BY clause.</dd>)^
4219**
4220** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
4221** <dd>The maximum depth of the parse tree on any expression.</dd>)^
4222**
4223** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
4224** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
4225**
4226** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
4227** <dd>The maximum number of instructions in a virtual machine program
4228** used to implement an SQL statement. If [sqlite3_prepare_v2()] or
4229** the equivalent tries to allocate space for more than this many opcodes
4230** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
4231**
4232** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
4233** <dd>The maximum number of arguments on a function.</dd>)^
4234**
4235** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
4236** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
4237**
4238** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
4239** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
4240** <dd>The maximum length of the pattern argument to the [LIKE] or
4241** [GLOB] operators.</dd>)^
4242**
4243** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
4244** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
4245** <dd>The maximum index number of any [parameter] in an SQL statement.)^
4246**
4247** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
4248** <dd>The maximum depth of recursion for triggers.</dd>)^
4249**
4250** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
4251** <dd>The maximum number of auxiliary worker threads that a single
4252** [prepared statement] may start.</dd>)^
4253** </dl>
4254*/
4255#define SQLITE_LIMIT_LENGTH 0
4256#define SQLITE_LIMIT_SQL_LENGTH 1
4257#define SQLITE_LIMIT_COLUMN 2
4258#define SQLITE_LIMIT_EXPR_DEPTH 3
4259#define SQLITE_LIMIT_COMPOUND_SELECT 4
4260#define SQLITE_LIMIT_VDBE_OP 5
4261#define SQLITE_LIMIT_FUNCTION_ARG 6
4262#define SQLITE_LIMIT_ATTACHED 7
4263#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
4264#define SQLITE_LIMIT_VARIABLE_NUMBER 9
4265#define SQLITE_LIMIT_TRIGGER_DEPTH 10
4266#define SQLITE_LIMIT_WORKER_THREADS 11
4267
4268/*
4269** CAPI3REF: Prepare Flags
4270**
4271** These constants define various flags that can be passed into
4272** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
4273** [sqlite3_prepare16_v3()] interfaces.
4274**
4275** New flags may be added in future releases of SQLite.
4276**
4277** <dl>
4278** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt>
4279** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
4280** that the prepared statement will be retained for a long time and
4281** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
4282** and [sqlite3_prepare16_v3()] assume that the prepared statement will
4283** be used just once or at most a few times and then destroyed using
4284** [sqlite3_finalize()] relatively soon. The current implementation acts
4285** on this hint by avoiding the use of [lookaside memory] so as not to
4286** deplete the limited store of lookaside memory. Future versions of
4287** SQLite may act on this hint differently.
4288**
4289** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt>
4290** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
4291** to be required for any prepared statement that wanted to use the
4292** [sqlite3_normalized_sql()] interface. However, the
4293** [sqlite3_normalized_sql()] interface is now available to all
4294** prepared statements, regardless of whether or not they use this
4295** flag.
4296**
4297** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt>
4298** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler
4299** to return an error (error code SQLITE_ERROR) if the statement uses
4300** any virtual tables.
4301**
4302** [[SQLITE_PREPARE_DONT_LOG]] <dt>SQLITE_PREPARE_DONT_LOG</dt>
4303** <dd>The SQLITE_PREPARE_DONT_LOG flag prevents SQL compiler
4304** errors from being sent to the error log defined by
4305** [SQLITE_CONFIG_LOG]. This can be used, for example, to do test
4306** compiles to see if some SQL syntax is well-formed, without generating
4307** messages on the global error log when it is not. If the test compile
4308** fails, the sqlite3_prepare_v3() call returns the same error indications
4309** with or without this flag; it just omits the call to [sqlite3_log()] that
4310** logs the error.
4311** </dl>
4312*/
4313#define SQLITE_PREPARE_PERSISTENT 0x01
4314#define SQLITE_PREPARE_NORMALIZE 0x02
4315#define SQLITE_PREPARE_NO_VTAB 0x04
4316#define SQLITE_PREPARE_DONT_LOG 0x10
4317
4318/*
4319** CAPI3REF: Compiling An SQL Statement
4320** KEYWORDS: {SQL statement compiler}
4321** METHOD: sqlite3
4322** CONSTRUCTOR: sqlite3_stmt
4323**
4324** To execute an SQL statement, it must first be compiled into a byte-code
4325** program using one of these routines. Or, in other words, these routines
4326** are constructors for the [prepared statement] object.
4327**
4328** The preferred routine to use is [sqlite3_prepare_v2()]. The
4329** [sqlite3_prepare()] interface is legacy and should be avoided.
4330** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
4331** for special purposes.
4332**
4333** The use of the UTF-8 interfaces is preferred, as SQLite currently
4334** does all parsing using UTF-8. The UTF-16 interfaces are provided
4335** as a convenience. The UTF-16 interfaces work by converting the
4336** input text into UTF-8, then invoking the corresponding UTF-8 interface.
4337**
4338** The first argument, "db", is a [database connection] obtained from a
4339** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
4340** [sqlite3_open16()]. The database connection must not have been closed.
4341**
4342** The second argument, "zSql", is the statement to be compiled, encoded
4343** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(),
4344** and sqlite3_prepare_v3()
4345** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
4346** and sqlite3_prepare16_v3() use UTF-16.
4347**
4348** ^If the nByte argument is negative, then zSql is read up to the
4349** first zero terminator. ^If nByte is positive, then it is the maximum
4350** number of bytes read from zSql. When nByte is positive, zSql is read
4351** up to the first zero terminator or until the nByte bytes have been read,
4352** whichever comes first. ^If nByte is zero, then no prepared
4353** statement is generated.
4354** If the caller knows that the supplied string is nul-terminated, then
4355** there is a small performance advantage to passing an nByte parameter that
4356** is the number of bytes in the input string <i>including</i>
4357** the nul-terminator.
4358** Note that nByte measure the length of the input in bytes, not
4359** characters, even for the UTF-16 interfaces.
4360**
4361** ^If pzTail is not NULL then *pzTail is made to point to the first byte
4362** past the end of the first SQL statement in zSql. These routines only
4363** compile the first statement in zSql, so *pzTail is left pointing to
4364** what remains uncompiled.
4365**
4366** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
4367** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
4368** to NULL. ^If the input text contains no SQL (if the input is an empty
4369** string or a comment) then *ppStmt is set to NULL.
4370** The calling procedure is responsible for deleting the compiled
4371** SQL statement using [sqlite3_finalize()] after it has finished with it.
4372** ppStmt may not be NULL.
4373**
4374** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
4375** otherwise an [error code] is returned.
4376**
4377** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
4378** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
4379** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
4380** are retained for backwards compatibility, but their use is discouraged.
4381** ^In the "vX" interfaces, the prepared statement
4382** that is returned (the [sqlite3_stmt] object) contains a copy of the
4383** original SQL text. This causes the [sqlite3_step()] interface to
4384** behave differently in three ways:
4385**
4386** <ol>
4387** <li>
4388** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
4389** always used to do, [sqlite3_step()] will automatically recompile the SQL
4390** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
4391** retries will occur before sqlite3_step() gives up and returns an error.
4392** </li>
4393**
4394** <li>
4395** ^When an error occurs, [sqlite3_step()] will return one of the detailed
4396** [error codes] or [extended error codes]. ^The legacy behavior was that
4397** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
4398** and the application would have to make a second call to [sqlite3_reset()]
4399** in order to find the underlying cause of the problem. With the "v2" prepare
4400** interfaces, the underlying reason for the error is returned immediately.
4401** </li>
4402**
4403** <li>
4404** ^If the specific value bound to a [parameter | host parameter] in the
4405** WHERE clause might influence the choice of query plan for a statement,
4406** then the statement will be automatically recompiled, as if there had been
4407** a schema change, on the first [sqlite3_step()] call following any change
4408** to the [sqlite3_bind_text | bindings] of that [parameter].
4409** ^The specific value of a WHERE-clause [parameter] might influence the
4410** choice of query plan if the parameter is the left-hand side of a [LIKE]
4411** or [GLOB] operator or if the parameter is compared to an indexed column
4412** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled.
4413** </li>
4414** </ol>
4415**
4416** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
4417** the extra prepFlags parameter, which is a bit array consisting of zero or
4418** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The
4419** sqlite3_prepare_v2() interface works exactly the same as
4420** sqlite3_prepare_v3() with a zero prepFlags parameter.
4421*/
4422SQLITE_API int sqlite3_prepare(
4423 sqlite3 *db, /* Database handle */
4424 const char *zSql, /* SQL statement, UTF-8 encoded */
4425 int nByte, /* Maximum length of zSql in bytes. */
4426 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
4427 const char **pzTail /* OUT: Pointer to unused portion of zSql */
4428);
4429SQLITE_API int sqlite3_prepare_v2(
4430 sqlite3 *db, /* Database handle */
4431 const char *zSql, /* SQL statement, UTF-8 encoded */
4432 int nByte, /* Maximum length of zSql in bytes. */
4433 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
4434 const char **pzTail /* OUT: Pointer to unused portion of zSql */
4435);
4436SQLITE_API int sqlite3_prepare_v3(
4437 sqlite3 *db, /* Database handle */
4438 const char *zSql, /* SQL statement, UTF-8 encoded */
4439 int nByte, /* Maximum length of zSql in bytes. */
4440 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
4441 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
4442 const char **pzTail /* OUT: Pointer to unused portion of zSql */
4443);
4444SQLITE_API int sqlite3_prepare16(
4445 sqlite3 *db, /* Database handle */
4446 const void *zSql, /* SQL statement, UTF-16 encoded */
4447 int nByte, /* Maximum length of zSql in bytes. */
4448 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
4449 const void **pzTail /* OUT: Pointer to unused portion of zSql */
4450);
4451SQLITE_API int sqlite3_prepare16_v2(
4452 sqlite3 *db, /* Database handle */
4453 const void *zSql, /* SQL statement, UTF-16 encoded */
4454 int nByte, /* Maximum length of zSql in bytes. */
4455 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
4456 const void **pzTail /* OUT: Pointer to unused portion of zSql */
4457);
4458SQLITE_API int sqlite3_prepare16_v3(
4459 sqlite3 *db, /* Database handle */
4460 const void *zSql, /* SQL statement, UTF-16 encoded */
4461 int nByte, /* Maximum length of zSql in bytes. */
4462 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
4463 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
4464 const void **pzTail /* OUT: Pointer to unused portion of zSql */
4465);
4466
4467/*
4468** CAPI3REF: Retrieving Statement SQL
4469** METHOD: sqlite3_stmt
4470**
4471** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
4472** SQL text used to create [prepared statement] P if P was
4473** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
4474** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4475** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
4476** string containing the SQL text of prepared statement P with
4477** [bound parameters] expanded.
4478** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8
4479** string containing the normalized SQL text of prepared statement P. The
4480** semantics used to normalize a SQL statement are unspecified and subject
4481** to change. At a minimum, literal values will be replaced with suitable
4482** placeholders.
4483**
4484** ^(For example, if a prepared statement is created using the SQL
4485** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
4486** and parameter :xyz is unbound, then sqlite3_sql() will return
4487** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
4488** will return "SELECT 2345,NULL".)^
4489**
4490** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
4491** is available to hold the result, or if the result would exceed the
4492** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
4493**
4494** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
4495** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time
4496** option causes sqlite3_expanded_sql() to always return NULL.
4497**
4498** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P)
4499** are managed by SQLite and are automatically freed when the prepared
4500** statement is finalized.
4501** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
4502** is obtained from [sqlite3_malloc()] and must be freed by the application
4503** by passing it to [sqlite3_free()].
4504**
4505** ^The sqlite3_normalized_sql() interface is only available if
4506** the [SQLITE_ENABLE_NORMALIZE] compile-time option is defined.
4507*/
4508SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
4509SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
4510#ifdef SQLITE_ENABLE_NORMALIZE
4511SQLITE_API const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt);
4512#endif
4513
4514/*
4515** CAPI3REF: Determine If An SQL Statement Writes The Database
4516** METHOD: sqlite3_stmt
4517**
4518** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
4519** and only if the [prepared statement] X makes no direct changes to
4520** the content of the database file.
4521**
4522** Note that [application-defined SQL functions] or
4523** [virtual tables] might change the database indirectly as a side effect.
4524** ^(For example, if an application defines a function "eval()" that
4525** calls [sqlite3_exec()], then the following SQL statement would
4526** change the database file through side-effects:
4527**
4528** <blockquote><pre>
4529** SELECT eval('DELETE FROM t1') FROM t2;
4530** </pre></blockquote>
4531**
4532** But because the [SELECT] statement does not change the database file
4533** directly, sqlite3_stmt_readonly() would still return true.)^
4534**
4535** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
4536** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
4537** since the statements themselves do not actually modify the database but
4538** rather they control the timing of when other statements modify the
4539** database. ^The [ATTACH] and [DETACH] statements also cause
4540** sqlite3_stmt_readonly() to return true since, while those statements
4541** change the configuration of a database connection, they do not make
4542** changes to the content of the database files on disk.
4543** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
4544** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
4545** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
4546** sqlite3_stmt_readonly() returns false for those commands.
4547**
4548** ^This routine returns false if there is any possibility that the
4549** statement might change the database file. ^A false return does
4550** not guarantee that the statement will change the database file.
4551** ^For example, an UPDATE statement might have a WHERE clause that
4552** makes it a no-op, but the sqlite3_stmt_readonly() result would still
4553** be false. ^Similarly, a CREATE TABLE IF NOT EXISTS statement is a
4554** read-only no-op if the table already exists, but
4555** sqlite3_stmt_readonly() still returns false for such a statement.
4556**
4557** ^If prepared statement X is an [EXPLAIN] or [EXPLAIN QUERY PLAN]
4558** statement, then sqlite3_stmt_readonly(X) returns the same value as
4559** if the EXPLAIN or EXPLAIN QUERY PLAN prefix were omitted.
4560*/
4561SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
4562
4563/*
4564** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement
4565** METHOD: sqlite3_stmt
4566**
4567** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the
4568** prepared statement S is an EXPLAIN statement, or 2 if the
4569** statement S is an EXPLAIN QUERY PLAN.
4570** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is
4571** an ordinary statement or a NULL pointer.
4572*/
4573SQLITE_API int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt);
4574
4575/*
4576** CAPI3REF: Change The EXPLAIN Setting For A Prepared Statement
4577** METHOD: sqlite3_stmt
4578**
4579** The sqlite3_stmt_explain(S,E) interface changes the EXPLAIN
4580** setting for [prepared statement] S. If E is zero, then S becomes
4581** a normal prepared statement. If E is 1, then S behaves as if
4582** its SQL text began with "[EXPLAIN]". If E is 2, then S behaves as if
4583** its SQL text began with "[EXPLAIN QUERY PLAN]".
4584**
4585** Calling sqlite3_stmt_explain(S,E) might cause S to be reprepared.
4586** SQLite tries to avoid a reprepare, but a reprepare might be necessary
4587** on the first transition into EXPLAIN or EXPLAIN QUERY PLAN mode.
4588**
4589** Because of the potential need to reprepare, a call to
4590** sqlite3_stmt_explain(S,E) will fail with SQLITE_ERROR if S cannot be
4591** reprepared because it was created using [sqlite3_prepare()] instead of
4592** the newer [sqlite3_prepare_v2()] or [sqlite3_prepare_v3()] interfaces and
4593** hence has no saved SQL text with which to reprepare.
4594**
4595** Changing the explain setting for a prepared statement does not change
4596** the original SQL text for the statement. Hence, if the SQL text originally
4597** began with EXPLAIN or EXPLAIN QUERY PLAN, but sqlite3_stmt_explain(S,0)
4598** is called to convert the statement into an ordinary statement, the EXPLAIN
4599** or EXPLAIN QUERY PLAN keywords will still appear in the sqlite3_sql(S)
4600** output, even though the statement now acts like a normal SQL statement.
4601**
4602** This routine returns SQLITE_OK if the explain mode is successfully
4603** changed, or an error code if the explain mode could not be changed.
4604** The explain mode cannot be changed while a statement is active.
4605** Hence, it is good practice to call [sqlite3_reset(S)]
4606** immediately prior to calling sqlite3_stmt_explain(S,E).
4607*/
4608SQLITE_API int sqlite3_stmt_explain(sqlite3_stmt *pStmt, int eMode);
4609
4610/*
4611** CAPI3REF: Determine If A Prepared Statement Has Been Reset
4612** METHOD: sqlite3_stmt
4613**
4614** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
4615** [prepared statement] S has been stepped at least once using
4616** [sqlite3_step(S)] but has neither run to completion (returned
4617** [SQLITE_DONE] from [sqlite3_step(S)]) nor
4618** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
4619** interface returns false if S is a NULL pointer. If S is not a
4620** NULL pointer and is not a pointer to a valid [prepared statement]
4621** object, then the behavior is undefined and probably undesirable.
4622**
4623** This interface can be used in combination [sqlite3_next_stmt()]
4624** to locate all prepared statements associated with a database
4625** connection that are in need of being reset. This can be used,
4626** for example, in diagnostic routines to search for prepared
4627** statements that are holding a transaction open.
4628*/
4629SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
4630
4631/*
4632** CAPI3REF: Dynamically Typed Value Object
4633** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
4634**
4635** SQLite uses the sqlite3_value object to represent all values
4636** that can be stored in a database table. SQLite uses dynamic typing
4637** for the values it stores. ^Values stored in sqlite3_value objects
4638** can be integers, floating point values, strings, BLOBs, or NULL.
4639**
4640** An sqlite3_value object may be either "protected" or "unprotected".
4641** Some interfaces require a protected sqlite3_value. Other interfaces
4642** will accept either a protected or an unprotected sqlite3_value.
4643** Every interface that accepts sqlite3_value arguments specifies
4644** whether or not it requires a protected sqlite3_value. The
4645** [sqlite3_value_dup()] interface can be used to construct a new
4646** protected sqlite3_value from an unprotected sqlite3_value.
4647**
4648** The terms "protected" and "unprotected" refer to whether or not
4649** a mutex is held. An internal mutex is held for a protected
4650** sqlite3_value object but no mutex is held for an unprotected
4651** sqlite3_value object. If SQLite is compiled to be single-threaded
4652** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
4653** or if SQLite is run in one of reduced mutex modes
4654** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
4655** then there is no distinction between protected and unprotected
4656** sqlite3_value objects and they can be used interchangeably. However,
4657** for maximum code portability it is recommended that applications
4658** still make the distinction between protected and unprotected
4659** sqlite3_value objects even when not strictly required.
4660**
4661** ^The sqlite3_value objects that are passed as parameters into the
4662** implementation of [application-defined SQL functions] are protected.
4663** ^The sqlite3_value objects returned by [sqlite3_vtab_rhs_value()]
4664** are protected.
4665** ^The sqlite3_value object returned by
4666** [sqlite3_column_value()] is unprotected.
4667** Unprotected sqlite3_value objects may only be used as arguments
4668** to [sqlite3_result_value()], [sqlite3_bind_value()], and
4669** [sqlite3_value_dup()].
4670** The [sqlite3_value_blob | sqlite3_value_type()] family of
4671** interfaces require protected sqlite3_value objects.
4672*/
4673typedef struct sqlite3_value sqlite3_value;
4674
4675/*
4676** CAPI3REF: SQL Function Context Object
4677**
4678** The context in which an SQL function executes is stored in an
4679** sqlite3_context object. ^A pointer to an sqlite3_context object
4680** is always first parameter to [application-defined SQL functions].
4681** The application-defined SQL function implementation will pass this
4682** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
4683** [sqlite3_aggregate_context()], [sqlite3_user_data()],
4684** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
4685** and/or [sqlite3_set_auxdata()].
4686*/
4687typedef struct sqlite3_context sqlite3_context;
4688
4689/*
4690** CAPI3REF: Binding Values To Prepared Statements
4691** KEYWORDS: {host parameter} {host parameters} {host parameter name}
4692** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
4693** METHOD: sqlite3_stmt
4694**
4695** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
4696** literals may be replaced by a [parameter] that matches one of following
4697** templates:
4698**
4699** <ul>
4700** <li> ?
4701** <li> ?NNN
4702** <li> :VVV
4703** <li> @VVV
4704** <li> $VVV
4705** </ul>
4706**
4707** In the templates above, NNN represents an integer literal,
4708** and VVV represents an alphanumeric identifier.)^ ^The values of these
4709** parameters (also called "host parameter names" or "SQL parameters")
4710** can be set using the sqlite3_bind_*() routines defined here.
4711**
4712** ^The first argument to the sqlite3_bind_*() routines is always
4713** a pointer to the [sqlite3_stmt] object returned from
4714** [sqlite3_prepare_v2()] or its variants.
4715**
4716** ^The second argument is the index of the SQL parameter to be set.
4717** ^The leftmost SQL parameter has an index of 1. ^When the same named
4718** SQL parameter is used more than once, second and subsequent
4719** occurrences have the same index as the first occurrence.
4720** ^The index for named parameters can be looked up using the
4721** [sqlite3_bind_parameter_index()] API if desired. ^The index
4722** for "?NNN" parameters is the value of NNN.
4723** ^The NNN value must be between 1 and the [sqlite3_limit()]
4724** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766).
4725**
4726** ^The third argument is the value to bind to the parameter.
4727** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
4728** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
4729** is ignored and the end result is the same as sqlite3_bind_null().
4730** ^If the third parameter to sqlite3_bind_text() is not NULL, then
4731** it should be a pointer to well-formed UTF8 text.
4732** ^If the third parameter to sqlite3_bind_text16() is not NULL, then
4733** it should be a pointer to well-formed UTF16 text.
4734** ^If the third parameter to sqlite3_bind_text64() is not NULL, then
4735** it should be a pointer to a well-formed unicode string that is
4736** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16
4737** otherwise.
4738**
4739** [[byte-order determination rules]] ^The byte-order of
4740** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF)
4741** found in first character, which is removed, or in the absence of a BOM
4742** the byte order is the native byte order of the host
4743** machine for sqlite3_bind_text16() or the byte order specified in
4744** the 6th parameter for sqlite3_bind_text64().)^
4745** ^If UTF16 input text contains invalid unicode
4746** characters, then SQLite might change those invalid characters
4747** into the unicode replacement character: U+FFFD.
4748**
4749** ^(In those routines that have a fourth argument, its value is the
4750** number of bytes in the parameter. To be clear: the value is the
4751** number of <u>bytes</u> in the value, not the number of characters.)^
4752** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
4753** is negative, then the length of the string is
4754** the number of bytes up to the first zero terminator.
4755** If the fourth parameter to sqlite3_bind_blob() is negative, then
4756** the behavior is undefined.
4757** If a non-negative fourth parameter is provided to sqlite3_bind_text()
4758** or sqlite3_bind_text16() or sqlite3_bind_text64() then
4759** that parameter must be the byte offset
4760** where the NUL terminator would occur assuming the string were NUL
4761** terminated. If any NUL characters occurs at byte offsets less than
4762** the value of the fourth parameter then the resulting string value will
4763** contain embedded NULs. The result of expressions involving strings
4764** with embedded NULs is undefined.
4765**
4766** ^The fifth argument to the BLOB and string binding interfaces controls
4767** or indicates the lifetime of the object referenced by the third parameter.
4768** These three options exist:
4769** ^ (1) A destructor to dispose of the BLOB or string after SQLite has finished
4770** with it may be passed. ^It is called to dispose of the BLOB or string even
4771** if the call to the bind API fails, except the destructor is not called if
4772** the third parameter is a NULL pointer or the fourth parameter is negative.
4773** ^ (2) The special constant, [SQLITE_STATIC], may be passed to indicate that
4774** the application remains responsible for disposing of the object. ^In this
4775** case, the object and the provided pointer to it must remain valid until
4776** either the prepared statement is finalized or the same SQL parameter is
4777** bound to something else, whichever occurs sooner.
4778** ^ (3) The constant, [SQLITE_TRANSIENT], may be passed to indicate that the
4779** object is to be copied prior to the return from sqlite3_bind_*(). ^The
4780** object and pointer to it must remain valid until then. ^SQLite will then
4781** manage the lifetime of its private copy.
4782**
4783** ^The sixth argument to sqlite3_bind_text64() must be one of
4784** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
4785** to specify the encoding of the text in the third parameter. If
4786** the sixth argument to sqlite3_bind_text64() is not one of the
4787** allowed values shown above, or if the text encoding is different
4788** from the encoding specified by the sixth parameter, then the behavior
4789** is undefined.
4790**
4791** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
4792** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
4793** (just an integer to hold its size) while it is being processed.
4794** Zeroblobs are intended to serve as placeholders for BLOBs whose
4795** content is later written using
4796** [sqlite3_blob_open | incremental BLOB I/O] routines.
4797** ^A negative value for the zeroblob results in a zero-length BLOB.
4798**
4799** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
4800** [prepared statement] S to have an SQL value of NULL, but to also be
4801** associated with the pointer P of type T. ^D is either a NULL pointer or
4802** a pointer to a destructor function for P. ^SQLite will invoke the
4803** destructor D with a single argument of P when it is finished using
4804** P. The T parameter should be a static string, preferably a string
4805** literal. The sqlite3_bind_pointer() routine is part of the
4806** [pointer passing interface] added for SQLite 3.20.0.
4807**
4808** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
4809** for the [prepared statement] or with a prepared statement for which
4810** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
4811** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
4812** routine is passed a [prepared statement] that has been finalized, the
4813** result is undefined and probably harmful.
4814**
4815** ^Bindings are not cleared by the [sqlite3_reset()] routine.
4816** ^Unbound parameters are interpreted as NULL.
4817**
4818** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
4819** [error code] if anything goes wrong.
4820** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
4821** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
4822** [SQLITE_MAX_LENGTH].
4823** ^[SQLITE_RANGE] is returned if the parameter
4824** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
4825**
4826** See also: [sqlite3_bind_parameter_count()],
4827** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
4828*/
4829SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
4830SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
4831 void(*)(void*));
4832SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
4833SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
4834SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
4835SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
4836SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
4837SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
4838SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
4839 void(*)(void*), unsigned char encoding);
4840SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
4841SQLITE_API int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
4842SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
4843SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
4844
4845/*
4846** CAPI3REF: Number Of SQL Parameters
4847** METHOD: sqlite3_stmt
4848**
4849** ^This routine can be used to find the number of [SQL parameters]
4850** in a [prepared statement]. SQL parameters are tokens of the
4851** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
4852** placeholders for values that are [sqlite3_bind_blob | bound]
4853** to the parameters at a later time.
4854**
4855** ^(This routine actually returns the index of the largest (rightmost)
4856** parameter. For all forms except ?NNN, this will correspond to the
4857** number of unique parameters. If parameters of the ?NNN form are used,
4858** there may be gaps in the list.)^
4859**
4860** See also: [sqlite3_bind_blob|sqlite3_bind()],
4861** [sqlite3_bind_parameter_name()], and
4862** [sqlite3_bind_parameter_index()].
4863*/
4864SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
4865
4866/*
4867** CAPI3REF: Name Of A Host Parameter
4868** METHOD: sqlite3_stmt
4869**
4870** ^The sqlite3_bind_parameter_name(P,N) interface returns
4871** the name of the N-th [SQL parameter] in the [prepared statement] P.
4872** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
4873** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
4874** respectively.
4875** In other words, the initial ":" or "$" or "@" or "?"
4876** is included as part of the name.)^
4877** ^Parameters of the form "?" without a following integer have no name
4878** and are referred to as "nameless" or "anonymous parameters".
4879**
4880** ^The first host parameter has an index of 1, not 0.
4881**
4882** ^If the value N is out of range or if the N-th parameter is
4883** nameless, then NULL is returned. ^The returned string is
4884** always in UTF-8 encoding even if the named parameter was
4885** originally specified as UTF-16 in [sqlite3_prepare16()],
4886** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4887**
4888** See also: [sqlite3_bind_blob|sqlite3_bind()],
4889** [sqlite3_bind_parameter_count()], and
4890** [sqlite3_bind_parameter_index()].
4891*/
4892SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
4893
4894/*
4895** CAPI3REF: Index Of A Parameter With A Given Name
4896** METHOD: sqlite3_stmt
4897**
4898** ^Return the index of an SQL parameter given its name. ^The
4899** index value returned is suitable for use as the second
4900** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
4901** is returned if no matching parameter is found. ^The parameter
4902** name must be given in UTF-8 even if the original statement
4903** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
4904** [sqlite3_prepare16_v3()].
4905**
4906** See also: [sqlite3_bind_blob|sqlite3_bind()],
4907** [sqlite3_bind_parameter_count()], and
4908** [sqlite3_bind_parameter_name()].
4909*/
4910SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
4911
4912/*
4913** CAPI3REF: Reset All Bindings On A Prepared Statement
4914** METHOD: sqlite3_stmt
4915**
4916** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
4917** the [sqlite3_bind_blob | bindings] on a [prepared statement].
4918** ^Use this routine to reset all host parameters to NULL.
4919*/
4920SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
4921
4922/*
4923** CAPI3REF: Number Of Columns In A Result Set
4924** METHOD: sqlite3_stmt
4925**
4926** ^Return the number of columns in the result set returned by the
4927** [prepared statement]. ^If this routine returns 0, that means the
4928** [prepared statement] returns no data (for example an [UPDATE]).
4929** ^However, just because this routine returns a positive number does not
4930** mean that one or more rows of data will be returned. ^A SELECT statement
4931** will always have a positive sqlite3_column_count() but depending on the
4932** WHERE clause constraints and the table content, it might return no rows.
4933**
4934** See also: [sqlite3_data_count()]
4935*/
4936SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
4937
4938/*
4939** CAPI3REF: Column Names In A Result Set
4940** METHOD: sqlite3_stmt
4941**
4942** ^These routines return the name assigned to a particular column
4943** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
4944** interface returns a pointer to a zero-terminated UTF-8 string
4945** and sqlite3_column_name16() returns a pointer to a zero-terminated
4946** UTF-16 string. ^The first parameter is the [prepared statement]
4947** that implements the [SELECT] statement. ^The second parameter is the
4948** column number. ^The leftmost column is number 0.
4949**
4950** ^The returned string pointer is valid until either the [prepared statement]
4951** is destroyed by [sqlite3_finalize()] or until the statement is automatically
4952** reprepared by the first call to [sqlite3_step()] for a particular run
4953** or until the next call to
4954** sqlite3_column_name() or sqlite3_column_name16() on the same column.
4955**
4956** ^If sqlite3_malloc() fails during the processing of either routine
4957** (for example during a conversion from UTF-8 to UTF-16) then a
4958** NULL pointer is returned.
4959**
4960** ^The name of a result column is the value of the "AS" clause for
4961** that column, if there is an AS clause. If there is no AS clause
4962** then the name of the column is unspecified and may change from
4963** one release of SQLite to the next.
4964*/
4965SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
4966SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
4967
4968/*
4969** CAPI3REF: Source Of Data In A Query Result
4970** METHOD: sqlite3_stmt
4971**
4972** ^These routines provide a means to determine the database, table, and
4973** table column that is the origin of a particular result column in
4974** [SELECT] statement.
4975** ^The name of the database or table or column can be returned as
4976** either a UTF-8 or UTF-16 string. ^The _database_ routines return
4977** the database name, the _table_ routines return the table name, and
4978** the origin_ routines return the column name.
4979** ^The returned string is valid until the [prepared statement] is destroyed
4980** using [sqlite3_finalize()] or until the statement is automatically
4981** reprepared by the first call to [sqlite3_step()] for a particular run
4982** or until the same information is requested
4983** again in a different encoding.
4984**
4985** ^The names returned are the original un-aliased names of the
4986** database, table, and column.
4987**
4988** ^The first argument to these interfaces is a [prepared statement].
4989** ^These functions return information about the Nth result column returned by
4990** the statement, where N is the second function argument.
4991** ^The left-most column is column 0 for these routines.
4992**
4993** ^If the Nth column returned by the statement is an expression or
4994** subquery and is not a column value, then all of these functions return
4995** NULL. ^These routines might also return NULL if a memory allocation error
4996** occurs. ^Otherwise, they return the name of the attached database, table,
4997** or column that query result column was extracted from.
4998**
4999** ^As with all other SQLite APIs, those whose names end with "16" return
5000** UTF-16 encoded strings and the other functions return UTF-8.
5001**
5002** ^These APIs are only available if the library was compiled with the
5003** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
5004**
5005** If two or more threads call one or more
5006** [sqlite3_column_database_name | column metadata interfaces]
5007** for the same [prepared statement] and result column
5008** at the same time then the results are undefined.
5009*/
5010SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
5011SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
5012SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
5013SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
5014SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
5015SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
5016
5017/*
5018** CAPI3REF: Declared Datatype Of A Query Result
5019** METHOD: sqlite3_stmt
5020**
5021** ^(The first parameter is a [prepared statement].
5022** If this statement is a [SELECT] statement and the Nth column of the
5023** returned result set of that [SELECT] is a table column (not an
5024** expression or subquery) then the declared type of the table
5025** column is returned.)^ ^If the Nth column of the result set is an
5026** expression or subquery, then a NULL pointer is returned.
5027** ^The returned string is always UTF-8 encoded.
5028**
5029** ^(For example, given the database schema:
5030**
5031** CREATE TABLE t1(c1 VARIANT);
5032**
5033** and the following statement to be compiled:
5034**
5035** SELECT c1 + 1, c1 FROM t1;
5036**
5037** this routine would return the string "VARIANT" for the second result
5038** column (i==1), and a NULL pointer for the first result column (i==0).)^
5039**
5040** ^SQLite uses dynamic run-time typing. ^So just because a column
5041** is declared to contain a particular type does not mean that the
5042** data stored in that column is of the declared type. SQLite is
5043** strongly typed, but the typing is dynamic not static. ^Type
5044** is associated with individual values, not with the containers
5045** used to hold those values.
5046*/
5047SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
5048SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
5049
5050/*
5051** CAPI3REF: Evaluate An SQL Statement
5052** METHOD: sqlite3_stmt
5053**
5054** After a [prepared statement] has been prepared using any of
5055** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
5056** or [sqlite3_prepare16_v3()] or one of the legacy
5057** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
5058** must be called one or more times to evaluate the statement.
5059**
5060** The details of the behavior of the sqlite3_step() interface depend
5061** on whether the statement was prepared using the newer "vX" interfaces
5062** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
5063** [sqlite3_prepare16_v2()] or the older legacy
5064** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
5065** new "vX" interface is recommended for new applications but the legacy
5066** interface will continue to be supported.
5067**
5068** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
5069** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
5070** ^With the "v2" interface, any of the other [result codes] or
5071** [extended result codes] might be returned as well.
5072**
5073** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
5074** database locks it needs to do its job. ^If the statement is a [COMMIT]
5075** or occurs outside of an explicit transaction, then you can retry the
5076** statement. If the statement is not a [COMMIT] and occurs within an
5077** explicit transaction then you should rollback the transaction before
5078** continuing.
5079**
5080** ^[SQLITE_DONE] means that the statement has finished executing
5081** successfully. sqlite3_step() should not be called again on this virtual
5082** machine without first calling [sqlite3_reset()] to reset the virtual
5083** machine back to its initial state.
5084**
5085** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
5086** is returned each time a new row of data is ready for processing by the
5087** caller. The values may be accessed using the [column access functions].
5088** sqlite3_step() is called again to retrieve the next row of data.
5089**
5090** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
5091** violation) has occurred. sqlite3_step() should not be called again on
5092** the VM. More information may be found by calling [sqlite3_errmsg()].
5093** ^With the legacy interface, a more specific error code (for example,
5094** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
5095** can be obtained by calling [sqlite3_reset()] on the
5096** [prepared statement]. ^In the "v2" interface,
5097** the more specific error code is returned directly by sqlite3_step().
5098**
5099** [SQLITE_MISUSE] means that the this routine was called inappropriately.
5100** Perhaps it was called on a [prepared statement] that has
5101** already been [sqlite3_finalize | finalized] or on one that had
5102** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
5103** be the case that the same database connection is being used by two or
5104** more threads at the same moment in time.
5105**
5106** For all versions of SQLite up to and including 3.6.23.1, a call to
5107** [sqlite3_reset()] was required after sqlite3_step() returned anything
5108** other than [SQLITE_ROW] before any subsequent invocation of
5109** sqlite3_step(). Failure to reset the prepared statement using
5110** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
5111** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1],
5112** sqlite3_step() began
5113** calling [sqlite3_reset()] automatically in this circumstance rather
5114** than returning [SQLITE_MISUSE]. This is not considered a compatibility
5115** break because any application that ever receives an SQLITE_MISUSE error
5116** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
5117** can be used to restore the legacy behavior.
5118**
5119** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
5120** API always returns a generic error code, [SQLITE_ERROR], following any
5121** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
5122** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
5123** specific [error codes] that better describes the error.
5124** We admit that this is a goofy design. The problem has been fixed
5125** with the "v2" interface. If you prepare all of your SQL statements
5126** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
5127** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
5128** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
5129** then the more specific [error codes] are returned directly
5130** by sqlite3_step(). The use of the "vX" interfaces is recommended.
5131*/
5132SQLITE_API int sqlite3_step(sqlite3_stmt*);
5133
5134/*
5135** CAPI3REF: Number of columns in a result set
5136** METHOD: sqlite3_stmt
5137**
5138** ^The sqlite3_data_count(P) interface returns the number of columns in the
5139** current row of the result set of [prepared statement] P.
5140** ^If prepared statement P does not have results ready to return
5141** (via calls to the [sqlite3_column_int | sqlite3_column()] family of
5142** interfaces) then sqlite3_data_count(P) returns 0.
5143** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
5144** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
5145** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
5146** will return non-zero if previous call to [sqlite3_step](P) returned
5147** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
5148** where it always returns zero since each step of that multi-step
5149** pragma returns 0 columns of data.
5150**
5151** See also: [sqlite3_column_count()]
5152*/
5153SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
5154
5155/*
5156** CAPI3REF: Fundamental Datatypes
5157** KEYWORDS: SQLITE_TEXT
5158**
5159** ^(Every value in SQLite has one of five fundamental datatypes:
5160**
5161** <ul>
5162** <li> 64-bit signed integer
5163** <li> 64-bit IEEE floating point number
5164** <li> string
5165** <li> BLOB
5166** <li> NULL
5167** </ul>)^
5168**
5169** These constants are codes for each of those types.
5170**
5171** Note that the SQLITE_TEXT constant was also used in SQLite version 2
5172** for a completely different meaning. Software that links against both
5173** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
5174** SQLITE_TEXT.
5175*/
5176#define SQLITE_INTEGER 1
5177#define SQLITE_FLOAT 2
5178#define SQLITE_BLOB 4
5179#define SQLITE_NULL 5
5180#ifdef SQLITE_TEXT
5181# undef SQLITE_TEXT
5182#else
5183# define SQLITE_TEXT 3
5184#endif
5185#define SQLITE3_TEXT 3
5186
5187/*
5188** CAPI3REF: Result Values From A Query
5189** KEYWORDS: {column access functions}
5190** METHOD: sqlite3_stmt
5191**
5192** <b>Summary:</b>
5193** <blockquote><table border=0 cellpadding=0 cellspacing=0>
5194** <tr><td><b>sqlite3_column_blob</b><td>&rarr;<td>BLOB result
5195** <tr><td><b>sqlite3_column_double</b><td>&rarr;<td>REAL result
5196** <tr><td><b>sqlite3_column_int</b><td>&rarr;<td>32-bit INTEGER result
5197** <tr><td><b>sqlite3_column_int64</b><td>&rarr;<td>64-bit INTEGER result
5198** <tr><td><b>sqlite3_column_text</b><td>&rarr;<td>UTF-8 TEXT result
5199** <tr><td><b>sqlite3_column_text16</b><td>&rarr;<td>UTF-16 TEXT result
5200** <tr><td><b>sqlite3_column_value</b><td>&rarr;<td>The result as an
5201** [sqlite3_value|unprotected sqlite3_value] object.
5202** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
5203** <tr><td><b>sqlite3_column_bytes</b><td>&rarr;<td>Size of a BLOB
5204** or a UTF-8 TEXT result in bytes
5205** <tr><td><b>sqlite3_column_bytes16&nbsp;&nbsp;</b>
5206** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
5207** TEXT in bytes
5208** <tr><td><b>sqlite3_column_type</b><td>&rarr;<td>Default
5209** datatype of the result
5210** </table></blockquote>
5211**
5212** <b>Details:</b>
5213**
5214** ^These routines return information about a single column of the current
5215** result row of a query. ^In every case the first argument is a pointer
5216** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
5217** that was returned from [sqlite3_prepare_v2()] or one of its variants)
5218** and the second argument is the index of the column for which information
5219** should be returned. ^The leftmost column of the result set has the index 0.
5220** ^The number of columns in the result can be determined using
5221** [sqlite3_column_count()].
5222**
5223** If the SQL statement does not currently point to a valid row, or if the
5224** column index is out of range, the result is undefined.
5225** These routines may only be called when the most recent call to
5226** [sqlite3_step()] has returned [SQLITE_ROW] and neither
5227** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
5228** If any of these routines are called after [sqlite3_reset()] or
5229** [sqlite3_finalize()] or after [sqlite3_step()] has returned
5230** something other than [SQLITE_ROW], the results are undefined.
5231** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
5232** are called from a different thread while any of these routines
5233** are pending, then the results are undefined.
5234**
5235** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
5236** each return the value of a result column in a specific data format. If
5237** the result column is not initially in the requested format (for example,
5238** if the query returns an integer but the sqlite3_column_text() interface
5239** is used to extract the value) then an automatic type conversion is performed.
5240**
5241** ^The sqlite3_column_type() routine returns the
5242** [SQLITE_INTEGER | datatype code] for the initial data type
5243** of the result column. ^The returned value is one of [SQLITE_INTEGER],
5244** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
5245** The return value of sqlite3_column_type() can be used to decide which
5246** of the first six interface should be used to extract the column value.
5247** The value returned by sqlite3_column_type() is only meaningful if no
5248** automatic type conversions have occurred for the value in question.
5249** After a type conversion, the result of calling sqlite3_column_type()
5250** is undefined, though harmless. Future
5251** versions of SQLite may change the behavior of sqlite3_column_type()
5252** following a type conversion.
5253**
5254** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
5255** or sqlite3_column_bytes16() interfaces can be used to determine the size
5256** of that BLOB or string.
5257**
5258** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
5259** routine returns the number of bytes in that BLOB or string.
5260** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
5261** the string to UTF-8 and then returns the number of bytes.
5262** ^If the result is a numeric value then sqlite3_column_bytes() uses
5263** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
5264** the number of bytes in that string.
5265** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
5266**
5267** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
5268** routine returns the number of bytes in that BLOB or string.
5269** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
5270** the string to UTF-16 and then returns the number of bytes.
5271** ^If the result is a numeric value then sqlite3_column_bytes16() uses
5272** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
5273** the number of bytes in that string.
5274** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
5275**
5276** ^The values returned by [sqlite3_column_bytes()] and
5277** [sqlite3_column_bytes16()] do not include the zero terminators at the end
5278** of the string. ^For clarity: the values returned by
5279** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
5280** bytes in the string, not the number of characters.
5281**
5282** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
5283** even empty strings, are always zero-terminated. ^The return
5284** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
5285**
5286** ^Strings returned by sqlite3_column_text16() always have the endianness
5287** which is native to the platform, regardless of the text encoding set
5288** for the database.
5289**
5290** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
5291** [unprotected sqlite3_value] object. In a multithreaded environment,
5292** an unprotected sqlite3_value object may only be used safely with
5293** [sqlite3_bind_value()] and [sqlite3_result_value()].
5294** If the [unprotected sqlite3_value] object returned by
5295** [sqlite3_column_value()] is used in any other way, including calls
5296** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
5297** or [sqlite3_value_bytes()], the behavior is not threadsafe.
5298** Hence, the sqlite3_column_value() interface
5299** is normally only useful within the implementation of
5300** [application-defined SQL functions] or [virtual tables], not within
5301** top-level application code.
5302**
5303** These routines may attempt to convert the datatype of the result.
5304** ^For example, if the internal representation is FLOAT and a text result
5305** is requested, [sqlite3_snprintf()] is used internally to perform the
5306** conversion automatically. ^(The following table details the conversions
5307** that are applied:
5308**
5309** <blockquote>
5310** <table border="1">
5311** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
5312**
5313** <tr><td> NULL <td> INTEGER <td> Result is 0
5314** <tr><td> NULL <td> FLOAT <td> Result is 0.0
5315** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer
5316** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer
5317** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
5318** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
5319** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
5320** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER
5321** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
5322** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB
5323** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER
5324** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL
5325** <tr><td> TEXT <td> BLOB <td> No change
5326** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER
5327** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL
5328** <tr><td> BLOB <td> TEXT <td> [CAST] to TEXT, ensure zero terminator
5329** </table>
5330** </blockquote>)^
5331**
5332** Note that when type conversions occur, pointers returned by prior
5333** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
5334** sqlite3_column_text16() may be invalidated.
5335** Type conversions and pointer invalidations might occur
5336** in the following cases:
5337**
5338** <ul>
5339** <li> The initial content is a BLOB and sqlite3_column_text() or
5340** sqlite3_column_text16() is called. A zero-terminator might
5341** need to be added to the string.</li>
5342** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
5343** sqlite3_column_text16() is called. The content must be converted
5344** to UTF-16.</li>
5345** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
5346** sqlite3_column_text() is called. The content must be converted
5347** to UTF-8.</li>
5348** </ul>
5349**
5350** ^Conversions between UTF-16be and UTF-16le are always done in place and do
5351** not invalidate a prior pointer, though of course the content of the buffer
5352** that the prior pointer references will have been modified. Other kinds
5353** of conversion are done in place when it is possible, but sometimes they
5354** are not possible and in those cases prior pointers are invalidated.
5355**
5356** The safest policy is to invoke these routines
5357** in one of the following ways:
5358**
5359** <ul>
5360** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
5361** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
5362** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
5363** </ul>
5364**
5365** In other words, you should call sqlite3_column_text(),
5366** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
5367** into the desired format, then invoke sqlite3_column_bytes() or
5368** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
5369** to sqlite3_column_text() or sqlite3_column_blob() with calls to
5370** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
5371** with calls to sqlite3_column_bytes().
5372**
5373** ^The pointers returned are valid until a type conversion occurs as
5374** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
5375** [sqlite3_finalize()] is called. ^The memory space used to hold strings
5376** and BLOBs is freed automatically. Do not pass the pointers returned
5377** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
5378** [sqlite3_free()].
5379**
5380** As long as the input parameters are correct, these routines will only
5381** fail if an out-of-memory error occurs during a format conversion.
5382** Only the following subset of interfaces are subject to out-of-memory
5383** errors:
5384**
5385** <ul>
5386** <li> sqlite3_column_blob()
5387** <li> sqlite3_column_text()
5388** <li> sqlite3_column_text16()
5389** <li> sqlite3_column_bytes()
5390** <li> sqlite3_column_bytes16()
5391** </ul>
5392**
5393** If an out-of-memory error occurs, then the return value from these
5394** routines is the same as if the column had contained an SQL NULL value.
5395** Valid SQL NULL returns can be distinguished from out-of-memory errors
5396** by invoking the [sqlite3_errcode()] immediately after the suspect
5397** return value is obtained and before any
5398** other SQLite interface is called on the same [database connection].
5399*/
5400SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
5401SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
5402SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
5403SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
5404SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
5405SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
5406SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
5407SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
5408SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
5409SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
5410
5411/*
5412** CAPI3REF: Destroy A Prepared Statement Object
5413** DESTRUCTOR: sqlite3_stmt
5414**
5415** ^The sqlite3_finalize() function is called to delete a [prepared statement].
5416** ^If the most recent evaluation of the statement encountered no errors
5417** or if the statement is never been evaluated, then sqlite3_finalize() returns
5418** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
5419** sqlite3_finalize(S) returns the appropriate [error code] or
5420** [extended error code].
5421**
5422** ^The sqlite3_finalize(S) routine can be called at any point during
5423** the life cycle of [prepared statement] S:
5424** before statement S is ever evaluated, after
5425** one or more calls to [sqlite3_reset()], or after any call
5426** to [sqlite3_step()] regardless of whether or not the statement has
5427** completed execution.
5428**
5429** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
5430**
5431** The application must finalize every [prepared statement] in order to avoid
5432** resource leaks. It is a grievous error for the application to try to use
5433** a prepared statement after it has been finalized. Any use of a prepared
5434** statement after it has been finalized can result in undefined and
5435** undesirable behavior such as segfaults and heap corruption.
5436*/
5437SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
5438
5439/*
5440** CAPI3REF: Reset A Prepared Statement Object
5441** METHOD: sqlite3_stmt
5442**
5443** The sqlite3_reset() function is called to reset a [prepared statement]
5444** object back to its initial state, ready to be re-executed.
5445** ^Any SQL statement variables that had values bound to them using
5446** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
5447** Use [sqlite3_clear_bindings()] to reset the bindings.
5448**
5449** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
5450** back to the beginning of its program.
5451**
5452** ^The return code from [sqlite3_reset(S)] indicates whether or not
5453** the previous evaluation of prepared statement S completed successfully.
5454** ^If [sqlite3_step(S)] has never before been called on S or if
5455** [sqlite3_step(S)] has not been called since the previous call
5456** to [sqlite3_reset(S)], then [sqlite3_reset(S)] will return
5457** [SQLITE_OK].
5458**
5459** ^If the most recent call to [sqlite3_step(S)] for the
5460** [prepared statement] S indicated an error, then
5461** [sqlite3_reset(S)] returns an appropriate [error code].
5462** ^The [sqlite3_reset(S)] interface might also return an [error code]
5463** if there were no prior errors but the process of resetting
5464** the prepared statement caused a new error. ^For example, if an
5465** [INSERT] statement with a [RETURNING] clause is only stepped one time,
5466** that one call to [sqlite3_step(S)] might return SQLITE_ROW but
5467** the overall statement might still fail and the [sqlite3_reset(S)] call
5468** might return SQLITE_BUSY if locking constraints prevent the
5469** database change from committing. Therefore, it is important that
5470** applications check the return code from [sqlite3_reset(S)] even if
5471** no prior call to [sqlite3_step(S)] indicated a problem.
5472**
5473** ^The [sqlite3_reset(S)] interface does not change the values
5474** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
5475*/
5476SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
5477
5478
5479/*
5480** CAPI3REF: Create Or Redefine SQL Functions
5481** KEYWORDS: {function creation routines}
5482** METHOD: sqlite3
5483**
5484** ^These functions (collectively known as "function creation routines")
5485** are used to add SQL functions or aggregates or to redefine the behavior
5486** of existing SQL functions or aggregates. The only differences between
5487** the three "sqlite3_create_function*" routines are the text encoding
5488** expected for the second parameter (the name of the function being
5489** created) and the presence or absence of a destructor callback for
5490** the application data pointer. Function sqlite3_create_window_function()
5491** is similar, but allows the user to supply the extra callback functions
5492** needed by [aggregate window functions].
5493**
5494** ^The first parameter is the [database connection] to which the SQL
5495** function is to be added. ^If an application uses more than one database
5496** connection then application-defined SQL functions must be added
5497** to each database connection separately.
5498**
5499** ^The second parameter is the name of the SQL function to be created or
5500** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
5501** representation, exclusive of the zero-terminator. ^Note that the name
5502** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
5503** ^Any attempt to create a function with a longer name
5504** will result in [SQLITE_MISUSE] being returned.
5505**
5506** ^The third parameter (nArg)
5507** is the number of arguments that the SQL function or
5508** aggregate takes. ^If this parameter is -1, then the SQL function or
5509** aggregate may take any number of arguments between 0 and the limit
5510** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
5511** parameter is less than -1 or greater than 127 then the behavior is
5512** undefined.
5513**
5514** ^The fourth parameter, eTextRep, specifies what
5515** [SQLITE_UTF8 | text encoding] this SQL function prefers for
5516** its parameters. The application should set this parameter to
5517** [SQLITE_UTF16LE] if the function implementation invokes
5518** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
5519** implementation invokes [sqlite3_value_text16be()] on an input, or
5520** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
5521** otherwise. ^The same SQL function may be registered multiple times using
5522** different preferred text encodings, with different implementations for
5523** each encoding.
5524** ^When multiple implementations of the same function are available, SQLite
5525** will pick the one that involves the least amount of data conversion.
5526**
5527** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
5528** to signal that the function will always return the same result given
5529** the same inputs within a single SQL statement. Most SQL functions are
5530** deterministic. The built-in [random()] SQL function is an example of a
5531** function that is not deterministic. The SQLite query planner is able to
5532** perform additional optimizations on deterministic functions, so use
5533** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
5534**
5535** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY]
5536** flag, which if present prevents the function from being invoked from
5537** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions,
5538** index expressions, or the WHERE clause of partial indexes.
5539**
5540** For best security, the [SQLITE_DIRECTONLY] flag is recommended for
5541** all application-defined SQL functions that do not need to be
5542** used inside of triggers, view, CHECK constraints, or other elements of
5543** the database schema. This flags is especially recommended for SQL
5544** functions that have side effects or reveal internal application state.
5545** Without this flag, an attacker might be able to modify the schema of
5546** a database file to include invocations of the function with parameters
5547** chosen by the attacker, which the application will then execute when
5548** the database file is opened and read.
5549**
5550** ^(The fifth parameter is an arbitrary pointer. The implementation of the
5551** function can gain access to this pointer using [sqlite3_user_data()].)^
5552**
5553** ^The sixth, seventh and eighth parameters passed to the three
5554** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are
5555** pointers to C-language functions that implement the SQL function or
5556** aggregate. ^A scalar SQL function requires an implementation of the xFunc
5557** callback only; NULL pointers must be passed as the xStep and xFinal
5558** parameters. ^An aggregate SQL function requires an implementation of xStep
5559** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
5560** SQL function or aggregate, pass NULL pointers for all three function
5561** callbacks.
5562**
5563** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue
5564** and xInverse) passed to sqlite3_create_window_function are pointers to
5565** C-language callbacks that implement the new function. xStep and xFinal
5566** must both be non-NULL. xValue and xInverse may either both be NULL, in
5567** which case a regular aggregate function is created, or must both be
5568** non-NULL, in which case the new function may be used as either an aggregate
5569** or aggregate window function. More details regarding the implementation
5570** of aggregate window functions are
5571** [user-defined window functions|available here].
5572**
5573** ^(If the final parameter to sqlite3_create_function_v2() or
5574** sqlite3_create_window_function() is not NULL, then it is destructor for
5575** the application data pointer. The destructor is invoked when the function
5576** is deleted, either by being overloaded or when the database connection
5577** closes.)^ ^The destructor is also invoked if the call to
5578** sqlite3_create_function_v2() fails. ^When the destructor callback is
5579** invoked, it is passed a single argument which is a copy of the application
5580** data pointer which was the fifth parameter to sqlite3_create_function_v2().
5581**
5582** ^It is permitted to register multiple implementations of the same
5583** functions with the same name but with either differing numbers of
5584** arguments or differing preferred text encodings. ^SQLite will use
5585** the implementation that most closely matches the way in which the
5586** SQL function is used. ^A function implementation with a non-negative
5587** nArg parameter is a better match than a function implementation with
5588** a negative nArg. ^A function where the preferred text encoding
5589** matches the database encoding is a better
5590** match than a function where the encoding is different.
5591** ^A function where the encoding difference is between UTF16le and UTF16be
5592** is a closer match than a function where the encoding difference is
5593** between UTF8 and UTF16.
5594**
5595** ^Built-in functions may be overloaded by new application-defined functions.
5596**
5597** ^An application-defined function is permitted to call other
5598** SQLite interfaces. However, such calls must not
5599** close the database connection nor finalize or reset the prepared
5600** statement in which the function is running.
5601*/
5602SQLITE_API int sqlite3_create_function(
5603 sqlite3 *db,
5604 const char *zFunctionName,
5605 int nArg,
5606 int eTextRep,
5607 void *pApp,
5608 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
5609 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5610 void (*xFinal)(sqlite3_context*)
5611);
5612SQLITE_API int sqlite3_create_function16(
5613 sqlite3 *db,
5614 const void *zFunctionName,
5615 int nArg,
5616 int eTextRep,
5617 void *pApp,
5618 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
5619 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5620 void (*xFinal)(sqlite3_context*)
5621);
5622SQLITE_API int sqlite3_create_function_v2(
5623 sqlite3 *db,
5624 const char *zFunctionName,
5625 int nArg,
5626 int eTextRep,
5627 void *pApp,
5628 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
5629 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5630 void (*xFinal)(sqlite3_context*),
5631 void(*xDestroy)(void*)
5632);
5633SQLITE_API int sqlite3_create_window_function(
5634 sqlite3 *db,
5635 const char *zFunctionName,
5636 int nArg,
5637 int eTextRep,
5638 void *pApp,
5639 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5640 void (*xFinal)(sqlite3_context*),
5641 void (*xValue)(sqlite3_context*),
5642 void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
5643 void(*xDestroy)(void*)
5644);
5645
5646/*
5647** CAPI3REF: Text Encodings
5648**
5649** These constant define integer codes that represent the various
5650** text encodings supported by SQLite.
5651*/
5652#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */
5653#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */
5654#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */
5655#define SQLITE_UTF16 4 /* Use native byte order */
5656#define SQLITE_ANY 5 /* Deprecated */
5657#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
5658
5659/*
5660** CAPI3REF: Function Flags
5661**
5662** These constants may be ORed together with the
5663** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
5664** to [sqlite3_create_function()], [sqlite3_create_function16()], or
5665** [sqlite3_create_function_v2()].
5666**
5667** <dl>
5668** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd>
5669** The SQLITE_DETERMINISTIC flag means that the new function always gives
5670** the same output when the input parameters are the same.
5671** The [abs|abs() function] is deterministic, for example, but
5672** [randomblob|randomblob()] is not. Functions must
5673** be deterministic in order to be used in certain contexts such as
5674** with the WHERE clause of [partial indexes] or in [generated columns].
5675** SQLite might also optimize deterministic functions by factoring them
5676** out of inner loops.
5677** </dd>
5678**
5679** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd>
5680** The SQLITE_DIRECTONLY flag means that the function may only be invoked
5681** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in
5682** schema structures such as [CHECK constraints], [DEFAULT clauses],
5683** [expression indexes], [partial indexes], or [generated columns].
5684** <p>
5685** The SQLITE_DIRECTONLY flag is recommended for any
5686** [application-defined SQL function]
5687** that has side-effects or that could potentially leak sensitive information.
5688** This will prevent attacks in which an application is tricked
5689** into using a database file that has had its schema surreptitiously
5690** modified to invoke the application-defined function in ways that are
5691** harmful.
5692** <p>
5693** Some people say it is good practice to set SQLITE_DIRECTONLY on all
5694** [application-defined SQL functions], regardless of whether or not they
5695** are security sensitive, as doing so prevents those functions from being used
5696** inside of the database schema, and thus ensures that the database
5697** can be inspected and modified using generic tools (such as the [CLI])
5698** that do not have access to the application-defined functions.
5699** </dd>
5700**
5701** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd>
5702** The SQLITE_INNOCUOUS flag means that the function is unlikely
5703** to cause problems even if misused. An innocuous function should have
5704** no side effects and should not depend on any values other than its
5705** input parameters. The [abs|abs() function] is an example of an
5706** innocuous function.
5707** The [load_extension() SQL function] is not innocuous because of its
5708** side effects.
5709** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not
5710** exactly the same. The [random|random() function] is an example of a
5711** function that is innocuous but not deterministic.
5712** <p>Some heightened security settings
5713** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF])
5714** disable the use of SQL functions inside views and triggers and in
5715** schema structures such as [CHECK constraints], [DEFAULT clauses],
5716** [expression indexes], [partial indexes], and [generated columns] unless
5717** the function is tagged with SQLITE_INNOCUOUS. Most built-in functions
5718** are innocuous. Developers are advised to avoid using the
5719** SQLITE_INNOCUOUS flag for application-defined functions unless the
5720** function has been carefully audited and found to be free of potentially
5721** security-adverse side-effects and information-leaks.
5722** </dd>
5723**
5724** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd>
5725** The SQLITE_SUBTYPE flag indicates to SQLite that a function might call
5726** [sqlite3_value_subtype()] to inspect the sub-types of its arguments.
5727** This flag instructs SQLite to omit some corner-case optimizations that
5728** might disrupt the operation of the [sqlite3_value_subtype()] function,
5729** causing it to return zero rather than the correct subtype().
5730** All SQL functions that invoke [sqlite3_value_subtype()] should have this
5731** property. If the SQLITE_SUBTYPE property is omitted, then the return
5732** value from [sqlite3_value_subtype()] might sometimes be zero even though
5733** a non-zero subtype was specified by the function argument expression.
5734**
5735** [[SQLITE_RESULT_SUBTYPE]] <dt>SQLITE_RESULT_SUBTYPE</dt><dd>
5736** The SQLITE_RESULT_SUBTYPE flag indicates to SQLite that a function might call
5737** [sqlite3_result_subtype()] to cause a sub-type to be associated with its
5738** result.
5739** Every function that invokes [sqlite3_result_subtype()] should have this
5740** property. If it does not, then the call to [sqlite3_result_subtype()]
5741** might become a no-op if the function is used as term in an
5742** [expression index]. On the other hand, SQL functions that never invoke
5743** [sqlite3_result_subtype()] should avoid setting this property, as the
5744** purpose of this property is to disable certain optimizations that are
5745** incompatible with subtypes.
5746**
5747** [[SQLITE_SELFORDER1]] <dt>SQLITE_SELFORDER1</dt><dd>
5748** The SQLITE_SELFORDER1 flag indicates that the function is an aggregate
5749** that internally orders the values provided to the first argument. The
5750** ordered-set aggregate SQL notation with a single ORDER BY term can be
5751** used to invoke this function. If the ordered-set aggregate notation is
5752** used on a function that lacks this flag, then an error is raised. Note
5753** that the ordered-set aggregate syntax is only available if SQLite is
5754** built using the -DSQLITE_ENABLE_ORDERED_SET_AGGREGATES compile-time option.
5755** </dd>
5756** </dl>
5757*/
5758#define SQLITE_DETERMINISTIC 0x000000800
5759#define SQLITE_DIRECTONLY 0x000080000
5760#define SQLITE_SUBTYPE 0x000100000
5761#define SQLITE_INNOCUOUS 0x000200000
5762#define SQLITE_RESULT_SUBTYPE 0x001000000
5763#define SQLITE_SELFORDER1 0x002000000
5764
5765/*
5766** CAPI3REF: Deprecated Functions
5767** DEPRECATED
5768**
5769** These functions are [deprecated]. In order to maintain
5770** backwards compatibility with older code, these functions continue
5771** to be supported. However, new applications should avoid
5772** the use of these functions. To encourage programmers to avoid
5773** these functions, we will not explain what they do.
5774*/
5775#ifndef SQLITE_OMIT_DEPRECATED
5776SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
5777SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
5778SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
5779SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
5780SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
5781SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
5782 void*,sqlite3_int64);
5783#endif
5784
5785/*
5786** CAPI3REF: Obtaining SQL Values
5787** METHOD: sqlite3_value
5788**
5789** <b>Summary:</b>
5790** <blockquote><table border=0 cellpadding=0 cellspacing=0>
5791** <tr><td><b>sqlite3_value_blob</b><td>&rarr;<td>BLOB value
5792** <tr><td><b>sqlite3_value_double</b><td>&rarr;<td>REAL value
5793** <tr><td><b>sqlite3_value_int</b><td>&rarr;<td>32-bit INTEGER value
5794** <tr><td><b>sqlite3_value_int64</b><td>&rarr;<td>64-bit INTEGER value
5795** <tr><td><b>sqlite3_value_pointer</b><td>&rarr;<td>Pointer value
5796** <tr><td><b>sqlite3_value_text</b><td>&rarr;<td>UTF-8 TEXT value
5797** <tr><td><b>sqlite3_value_text16</b><td>&rarr;<td>UTF-16 TEXT value in
5798** the native byteorder
5799** <tr><td><b>sqlite3_value_text16be</b><td>&rarr;<td>UTF-16be TEXT value
5800** <tr><td><b>sqlite3_value_text16le</b><td>&rarr;<td>UTF-16le TEXT value
5801** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
5802** <tr><td><b>sqlite3_value_bytes</b><td>&rarr;<td>Size of a BLOB
5803** or a UTF-8 TEXT in bytes
5804** <tr><td><b>sqlite3_value_bytes16&nbsp;&nbsp;</b>
5805** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
5806** TEXT in bytes
5807** <tr><td><b>sqlite3_value_type</b><td>&rarr;<td>Default
5808** datatype of the value
5809** <tr><td><b>sqlite3_value_numeric_type&nbsp;&nbsp;</b>
5810** <td>&rarr;&nbsp;&nbsp;<td>Best numeric datatype of the value
5811** <tr><td><b>sqlite3_value_nochange&nbsp;&nbsp;</b>
5812** <td>&rarr;&nbsp;&nbsp;<td>True if the column is unchanged in an UPDATE
5813** against a virtual table.
5814** <tr><td><b>sqlite3_value_frombind&nbsp;&nbsp;</b>
5815** <td>&rarr;&nbsp;&nbsp;<td>True if value originated from a [bound parameter]
5816** </table></blockquote>
5817**
5818** <b>Details:</b>
5819**
5820** These routines extract type, size, and content information from
5821** [protected sqlite3_value] objects. Protected sqlite3_value objects
5822** are used to pass parameter information into the functions that
5823** implement [application-defined SQL functions] and [virtual tables].
5824**
5825** These routines work only with [protected sqlite3_value] objects.
5826** Any attempt to use these routines on an [unprotected sqlite3_value]
5827** is not threadsafe.
5828**
5829** ^These routines work just like the corresponding [column access functions]
5830** except that these routines take a single [protected sqlite3_value] object
5831** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
5832**
5833** ^The sqlite3_value_text16() interface extracts a UTF-16 string
5834** in the native byte-order of the host machine. ^The
5835** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
5836** extract UTF-16 strings as big-endian and little-endian respectively.
5837**
5838** ^If [sqlite3_value] object V was initialized
5839** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
5840** and if X and Y are strings that compare equal according to strcmp(X,Y),
5841** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise,
5842** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
5843** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5844**
5845** ^(The sqlite3_value_type(V) interface returns the
5846** [SQLITE_INTEGER | datatype code] for the initial datatype of the
5847** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
5848** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
5849** Other interfaces might change the datatype for an sqlite3_value object.
5850** For example, if the datatype is initially SQLITE_INTEGER and
5851** sqlite3_value_text(V) is called to extract a text value for that
5852** integer, then subsequent calls to sqlite3_value_type(V) might return
5853** SQLITE_TEXT. Whether or not a persistent internal datatype conversion
5854** occurs is undefined and may change from one release of SQLite to the next.
5855**
5856** ^(The sqlite3_value_numeric_type() interface attempts to apply
5857** numeric affinity to the value. This means that an attempt is
5858** made to convert the value to an integer or floating point. If
5859** such a conversion is possible without loss of information (in other
5860** words, if the value is a string that looks like a number)
5861** then the conversion is performed. Otherwise no conversion occurs.
5862** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
5863**
5864** ^Within the [xUpdate] method of a [virtual table], the
5865** sqlite3_value_nochange(X) interface returns true if and only if
5866** the column corresponding to X is unchanged by the UPDATE operation
5867** that the xUpdate method call was invoked to implement and if
5868** and the prior [xColumn] method call that was invoked to extracted
5869** the value for that column returned without setting a result (probably
5870** because it queried [sqlite3_vtab_nochange()] and found that the column
5871** was unchanging). ^Within an [xUpdate] method, any value for which
5872** sqlite3_value_nochange(X) is true will in all other respects appear
5873** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other
5874** than within an [xUpdate] method call for an UPDATE statement, then
5875** the return value is arbitrary and meaningless.
5876**
5877** ^The sqlite3_value_frombind(X) interface returns non-zero if the
5878** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()]
5879** interfaces. ^If X comes from an SQL literal value, or a table column,
5880** or an expression, then sqlite3_value_frombind(X) returns zero.
5881**
5882** Please pay particular attention to the fact that the pointer returned
5883** from [sqlite3_value_blob()], [sqlite3_value_text()], or
5884** [sqlite3_value_text16()] can be invalidated by a subsequent call to
5885** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
5886** or [sqlite3_value_text16()].
5887**
5888** These routines must be called from the same thread as
5889** the SQL function that supplied the [sqlite3_value*] parameters.
5890**
5891** As long as the input parameter is correct, these routines can only
5892** fail if an out-of-memory error occurs during a format conversion.
5893** Only the following subset of interfaces are subject to out-of-memory
5894** errors:
5895**
5896** <ul>
5897** <li> sqlite3_value_blob()
5898** <li> sqlite3_value_text()
5899** <li> sqlite3_value_text16()
5900** <li> sqlite3_value_text16le()
5901** <li> sqlite3_value_text16be()
5902** <li> sqlite3_value_bytes()
5903** <li> sqlite3_value_bytes16()
5904** </ul>
5905**
5906** If an out-of-memory error occurs, then the return value from these
5907** routines is the same as if the column had contained an SQL NULL value.
5908** Valid SQL NULL returns can be distinguished from out-of-memory errors
5909** by invoking the [sqlite3_errcode()] immediately after the suspect
5910** return value is obtained and before any
5911** other SQLite interface is called on the same [database connection].
5912*/
5913SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
5914SQLITE_API double sqlite3_value_double(sqlite3_value*);
5915SQLITE_API int sqlite3_value_int(sqlite3_value*);
5916SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
5917SQLITE_API void *sqlite3_value_pointer(sqlite3_value*, const char*);
5918SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
5919SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
5920SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
5921SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
5922SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
5923SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
5924SQLITE_API int sqlite3_value_type(sqlite3_value*);
5925SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
5926SQLITE_API int sqlite3_value_nochange(sqlite3_value*);
5927SQLITE_API int sqlite3_value_frombind(sqlite3_value*);
5928
5929/*
5930** CAPI3REF: Report the internal text encoding state of an sqlite3_value object
5931** METHOD: sqlite3_value
5932**
5933** ^(The sqlite3_value_encoding(X) interface returns one of [SQLITE_UTF8],
5934** [SQLITE_UTF16BE], or [SQLITE_UTF16LE] according to the current text encoding
5935** of the value X, assuming that X has type TEXT.)^ If sqlite3_value_type(X)
5936** returns something other than SQLITE_TEXT, then the return value from
5937** sqlite3_value_encoding(X) is meaningless. ^Calls to
5938** [sqlite3_value_text(X)], [sqlite3_value_text16(X)], [sqlite3_value_text16be(X)],
5939** [sqlite3_value_text16le(X)], [sqlite3_value_bytes(X)], or
5940** [sqlite3_value_bytes16(X)] might change the encoding of the value X and
5941** thus change the return from subsequent calls to sqlite3_value_encoding(X).
5942**
5943** This routine is intended for used by applications that test and validate
5944** the SQLite implementation. This routine is inquiring about the opaque
5945** internal state of an [sqlite3_value] object. Ordinary applications should
5946** not need to know what the internal state of an sqlite3_value object is and
5947** hence should not need to use this interface.
5948*/
5949SQLITE_API int sqlite3_value_encoding(sqlite3_value*);
5950
5951/*
5952** CAPI3REF: Finding The Subtype Of SQL Values
5953** METHOD: sqlite3_value
5954**
5955** The sqlite3_value_subtype(V) function returns the subtype for
5956** an [application-defined SQL function] argument V. The subtype
5957** information can be used to pass a limited amount of context from
5958** one SQL function to another. Use the [sqlite3_result_subtype()]
5959** routine to set the subtype for the return value of an SQL function.
5960**
5961** Every [application-defined SQL function] that invokes this interface
5962** should include the [SQLITE_SUBTYPE] property in the text
5963** encoding argument when the function is [sqlite3_create_function|registered].
5964** If the [SQLITE_SUBTYPE] property is omitted, then sqlite3_value_subtype()
5965** might return zero instead of the upstream subtype in some corner cases.
5966*/
5967SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*);
5968
5969/*
5970** CAPI3REF: Copy And Free SQL Values
5971** METHOD: sqlite3_value
5972**
5973** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
5974** object D and returns a pointer to that copy. ^The [sqlite3_value] returned
5975** is a [protected sqlite3_value] object even if the input is not.
5976** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
5977** memory allocation fails. ^If V is a [pointer value], then the result
5978** of sqlite3_value_dup(V) is a NULL value.
5979**
5980** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
5981** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer
5982** then sqlite3_value_free(V) is a harmless no-op.
5983*/
5984SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
5985SQLITE_API void sqlite3_value_free(sqlite3_value*);
5986
5987/*
5988** CAPI3REF: Obtain Aggregate Function Context
5989** METHOD: sqlite3_context
5990**
5991** Implementations of aggregate SQL functions use this
5992** routine to allocate memory for storing their state.
5993**
5994** ^The first time the sqlite3_aggregate_context(C,N) routine is called
5995** for a particular aggregate function, SQLite allocates
5996** N bytes of memory, zeroes out that memory, and returns a pointer
5997** to the new memory. ^On second and subsequent calls to
5998** sqlite3_aggregate_context() for the same aggregate function instance,
5999** the same buffer is returned. Sqlite3_aggregate_context() is normally
6000** called once for each invocation of the xStep callback and then one
6001** last time when the xFinal callback is invoked. ^(When no rows match
6002** an aggregate query, the xStep() callback of the aggregate function
6003** implementation is never called and xFinal() is called exactly once.
6004** In those cases, sqlite3_aggregate_context() might be called for the
6005** first time from within xFinal().)^
6006**
6007** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
6008** when first called if N is less than or equal to zero or if a memory
6009** allocation error occurs.
6010**
6011** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
6012** determined by the N parameter on first successful call. Changing the
6013** value of N in any subsequent call to sqlite3_aggregate_context() within
6014** the same aggregate function instance will not resize the memory
6015** allocation.)^ Within the xFinal callback, it is customary to set
6016** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
6017** pointless memory allocations occur.
6018**
6019** ^SQLite automatically frees the memory allocated by
6020** sqlite3_aggregate_context() when the aggregate query concludes.
6021**
6022** The first parameter must be a copy of the
6023** [sqlite3_context | SQL function context] that is the first parameter
6024** to the xStep or xFinal callback routine that implements the aggregate
6025** function.
6026**
6027** This routine must be called from the same thread in which
6028** the aggregate SQL function is running.
6029*/
6030SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
6031
6032/*
6033** CAPI3REF: User Data For Functions
6034** METHOD: sqlite3_context
6035**
6036** ^The sqlite3_user_data() interface returns a copy of
6037** the pointer that was the pUserData parameter (the 5th parameter)
6038** of the [sqlite3_create_function()]
6039** and [sqlite3_create_function16()] routines that originally
6040** registered the application defined function.
6041**
6042** This routine must be called from the same thread in which
6043** the application-defined function is running.
6044*/
6045SQLITE_API void *sqlite3_user_data(sqlite3_context*);
6046
6047/*
6048** CAPI3REF: Database Connection For Functions
6049** METHOD: sqlite3_context
6050**
6051** ^The sqlite3_context_db_handle() interface returns a copy of
6052** the pointer to the [database connection] (the 1st parameter)
6053** of the [sqlite3_create_function()]
6054** and [sqlite3_create_function16()] routines that originally
6055** registered the application defined function.
6056*/
6057SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
6058
6059/*
6060** CAPI3REF: Function Auxiliary Data
6061** METHOD: sqlite3_context
6062**
6063** These functions may be used by (non-aggregate) SQL functions to
6064** associate auxiliary data with argument values. If the same argument
6065** value is passed to multiple invocations of the same SQL function during
6066** query execution, under some circumstances the associated auxiliary data
6067** might be preserved. An example of where this might be useful is in a
6068** regular-expression matching function. The compiled version of the regular
6069** expression can be stored as auxiliary data associated with the pattern string.
6070** Then as long as the pattern string remains the same,
6071** the compiled regular expression can be reused on multiple
6072** invocations of the same function.
6073**
6074** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the auxiliary data
6075** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
6076** value to the application-defined function. ^N is zero for the left-most
6077** function argument. ^If there is no auxiliary data
6078** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
6079** returns a NULL pointer.
6080**
6081** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as auxiliary data for the
6082** N-th argument of the application-defined function. ^Subsequent
6083** calls to sqlite3_get_auxdata(C,N) return P from the most recent
6084** sqlite3_set_auxdata(C,N,P,X) call if the auxiliary data is still valid or
6085** NULL if the auxiliary data has been discarded.
6086** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
6087** SQLite will invoke the destructor function X with parameter P exactly
6088** once, when the auxiliary data is discarded.
6089** SQLite is free to discard the auxiliary data at any time, including: <ul>
6090** <li> ^(when the corresponding function parameter changes)^, or
6091** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
6092** SQL statement)^, or
6093** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
6094** parameter)^, or
6095** <li> ^(during the original sqlite3_set_auxdata() call when a memory
6096** allocation error occurs.)^
6097** <li> ^(during the original sqlite3_set_auxdata() call if the function
6098** is evaluated during query planning instead of during query execution,
6099** as sometimes happens with [SQLITE_ENABLE_STAT4].)^ </ul>
6100**
6101** Note the last two bullets in particular. The destructor X in
6102** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
6103** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata()
6104** should be called near the end of the function implementation and the
6105** function implementation should not make any use of P after
6106** sqlite3_set_auxdata() has been called. Furthermore, a call to
6107** sqlite3_get_auxdata() that occurs immediately after a corresponding call
6108** to sqlite3_set_auxdata() might still return NULL if an out-of-memory
6109** condition occurred during the sqlite3_set_auxdata() call or if the
6110** function is being evaluated during query planning rather than during
6111** query execution.
6112**
6113** ^(In practice, auxiliary data is preserved between function calls for
6114** function parameters that are compile-time constants, including literal
6115** values and [parameters] and expressions composed from the same.)^
6116**
6117** The value of the N parameter to these interfaces should be non-negative.
6118** Future enhancements may make use of negative N values to define new
6119** kinds of function caching behavior.
6120**
6121** These routines must be called from the same thread in which
6122** the SQL function is running.
6123**
6124** See also: [sqlite3_get_clientdata()] and [sqlite3_set_clientdata()].
6125*/
6126SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
6127SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
6128
6129/*
6130** CAPI3REF: Database Connection Client Data
6131** METHOD: sqlite3
6132**
6133** These functions are used to associate one or more named pointers
6134** with a [database connection].
6135** A call to sqlite3_set_clientdata(D,N,P,X) causes the pointer P
6136** to be attached to [database connection] D using name N. Subsequent
6137** calls to sqlite3_get_clientdata(D,N) will return a copy of pointer P
6138** or a NULL pointer if there were no prior calls to
6139** sqlite3_set_clientdata() with the same values of D and N.
6140** Names are compared using strcmp() and are thus case sensitive.
6141**
6142** If P and X are both non-NULL, then the destructor X is invoked with
6143** argument P on the first of the following occurrences:
6144** <ul>
6145** <li> An out-of-memory error occurs during the call to
6146** sqlite3_set_clientdata() which attempts to register pointer P.
6147** <li> A subsequent call to sqlite3_set_clientdata(D,N,P,X) is made
6148** with the same D and N parameters.
6149** <li> The database connection closes. SQLite does not make any guarantees
6150** about the order in which destructors are called, only that all
6151** destructors will be called exactly once at some point during the
6152** database connection closing process.
6153** </ul>
6154**
6155** SQLite does not do anything with client data other than invoke
6156** destructors on the client data at the appropriate time. The intended
6157** use for client data is to provide a mechanism for wrapper libraries
6158** to store additional information about an SQLite database connection.
6159**
6160** There is no limit (other than available memory) on the number of different
6161** client data pointers (with different names) that can be attached to a
6162** single database connection. However, the implementation is optimized
6163** for the case of having only one or two different client data names.
6164** Applications and wrapper libraries are discouraged from using more than
6165** one client data name each.
6166**
6167** There is no way to enumerate the client data pointers
6168** associated with a database connection. The N parameter can be thought
6169** of as a secret key such that only code that knows the secret key is able
6170** to access the associated data.
6171**
6172** Security Warning: These interfaces should not be exposed in scripting
6173** languages or in other circumstances where it might be possible for an
6174** an attacker to invoke them. Any agent that can invoke these interfaces
6175** can probably also take control of the process.
6176**
6177** Database connection client data is only available for SQLite
6178** version 3.44.0 ([dateof:3.44.0]) and later.
6179**
6180** See also: [sqlite3_set_auxdata()] and [sqlite3_get_auxdata()].
6181*/
6182SQLITE_API void *sqlite3_get_clientdata(sqlite3*,const char*);
6183SQLITE_API int sqlite3_set_clientdata(sqlite3*, const char*, void*, void(*)(void*));
6184
6185/*
6186** CAPI3REF: Constants Defining Special Destructor Behavior
6187**
6188** These are special values for the destructor that is passed in as the
6189** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
6190** argument is SQLITE_STATIC, it means that the content pointer is constant
6191** and will never change. It does not need to be destroyed. ^The
6192** SQLITE_TRANSIENT value means that the content will likely change in
6193** the near future and that SQLite should make its own private copy of
6194** the content before returning.
6195**
6196** The typedef is necessary to work around problems in certain
6197** C++ compilers.
6198*/
6199typedef void (*sqlite3_destructor_type)(void*);
6200#define SQLITE_STATIC ((sqlite3_destructor_type)0)
6201#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
6202
6203/*
6204** CAPI3REF: Setting The Result Of An SQL Function
6205** METHOD: sqlite3_context
6206**
6207** These routines are used by the xFunc or xFinal callbacks that
6208** implement SQL functions and aggregates. See
6209** [sqlite3_create_function()] and [sqlite3_create_function16()]
6210** for additional information.
6211**
6212** These functions work very much like the [parameter binding] family of
6213** functions used to bind values to host parameters in prepared statements.
6214** Refer to the [SQL parameter] documentation for additional information.
6215**
6216** ^The sqlite3_result_blob() interface sets the result from
6217** an application-defined function to be the BLOB whose content is pointed
6218** to by the second parameter and which is N bytes long where N is the
6219** third parameter.
6220**
6221** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
6222** interfaces set the result of the application-defined function to be
6223** a BLOB containing all zero bytes and N bytes in size.
6224**
6225** ^The sqlite3_result_double() interface sets the result from
6226** an application-defined function to be a floating point value specified
6227** by its 2nd argument.
6228**
6229** ^The sqlite3_result_error() and sqlite3_result_error16() functions
6230** cause the implemented SQL function to throw an exception.
6231** ^SQLite uses the string pointed to by the
6232** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
6233** as the text of an error message. ^SQLite interprets the error
6234** message string from sqlite3_result_error() as UTF-8. ^SQLite
6235** interprets the string from sqlite3_result_error16() as UTF-16 using
6236** the same [byte-order determination rules] as [sqlite3_bind_text16()].
6237** ^If the third parameter to sqlite3_result_error()
6238** or sqlite3_result_error16() is negative then SQLite takes as the error
6239** message all text up through the first zero character.
6240** ^If the third parameter to sqlite3_result_error() or
6241** sqlite3_result_error16() is non-negative then SQLite takes that many
6242** bytes (not characters) from the 2nd parameter as the error message.
6243** ^The sqlite3_result_error() and sqlite3_result_error16()
6244** routines make a private copy of the error message text before
6245** they return. Hence, the calling function can deallocate or
6246** modify the text after they return without harm.
6247** ^The sqlite3_result_error_code() function changes the error code
6248** returned by SQLite as a result of an error in a function. ^By default,
6249** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
6250** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
6251**
6252** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
6253** error indicating that a string or BLOB is too long to represent.
6254**
6255** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
6256** error indicating that a memory allocation failed.
6257**
6258** ^The sqlite3_result_int() interface sets the return value
6259** of the application-defined function to be the 32-bit signed integer
6260** value given in the 2nd argument.
6261** ^The sqlite3_result_int64() interface sets the return value
6262** of the application-defined function to be the 64-bit signed integer
6263** value given in the 2nd argument.
6264**
6265** ^The sqlite3_result_null() interface sets the return value
6266** of the application-defined function to be NULL.
6267**
6268** ^The sqlite3_result_text(), sqlite3_result_text16(),
6269** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
6270** set the return value of the application-defined function to be
6271** a text string which is represented as UTF-8, UTF-16 native byte order,
6272** UTF-16 little endian, or UTF-16 big endian, respectively.
6273** ^The sqlite3_result_text64() interface sets the return value of an
6274** application-defined function to be a text string in an encoding
6275** specified by the fifth (and last) parameter, which must be one
6276** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
6277** ^SQLite takes the text result from the application from
6278** the 2nd parameter of the sqlite3_result_text* interfaces.
6279** ^If the 3rd parameter to any of the sqlite3_result_text* interfaces
6280** other than sqlite3_result_text64() is negative, then SQLite computes
6281** the string length itself by searching the 2nd parameter for the first
6282** zero character.
6283** ^If the 3rd parameter to the sqlite3_result_text* interfaces
6284** is non-negative, then as many bytes (not characters) of the text
6285** pointed to by the 2nd parameter are taken as the application-defined
6286** function result. If the 3rd parameter is non-negative, then it
6287** must be the byte offset into the string where the NUL terminator would
6288** appear if the string where NUL terminated. If any NUL characters occur
6289** in the string at a byte offset that is less than the value of the 3rd
6290** parameter, then the resulting string will contain embedded NULs and the
6291** result of expressions operating on strings with embedded NULs is undefined.
6292** ^If the 4th parameter to the sqlite3_result_text* interfaces
6293** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
6294** function as the destructor on the text or BLOB result when it has
6295** finished using that result.
6296** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
6297** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
6298** assumes that the text or BLOB result is in constant space and does not
6299** copy the content of the parameter nor call a destructor on the content
6300** when it has finished using that result.
6301** ^If the 4th parameter to the sqlite3_result_text* interfaces
6302** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
6303** then SQLite makes a copy of the result into space obtained
6304** from [sqlite3_malloc()] before it returns.
6305**
6306** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and
6307** sqlite3_result_text16be() routines, and for sqlite3_result_text64()
6308** when the encoding is not UTF8, if the input UTF16 begins with a
6309** byte-order mark (BOM, U+FEFF) then the BOM is removed from the
6310** string and the rest of the string is interpreted according to the
6311** byte-order specified by the BOM. ^The byte-order specified by
6312** the BOM at the beginning of the text overrides the byte-order
6313** specified by the interface procedure. ^So, for example, if
6314** sqlite3_result_text16le() is invoked with text that begins
6315** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the
6316** first two bytes of input are skipped and the remaining input
6317** is interpreted as UTF16BE text.
6318**
6319** ^For UTF16 input text to the sqlite3_result_text16(),
6320** sqlite3_result_text16be(), sqlite3_result_text16le(), and
6321** sqlite3_result_text64() routines, if the text contains invalid
6322** UTF16 characters, the invalid characters might be converted
6323** into the unicode replacement character, U+FFFD.
6324**
6325** ^The sqlite3_result_value() interface sets the result of
6326** the application-defined function to be a copy of the
6327** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
6328** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
6329** so that the [sqlite3_value] specified in the parameter may change or
6330** be deallocated after sqlite3_result_value() returns without harm.
6331** ^A [protected sqlite3_value] object may always be used where an
6332** [unprotected sqlite3_value] object is required, so either
6333** kind of [sqlite3_value] object can be used with this interface.
6334**
6335** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
6336** SQL NULL value, just like [sqlite3_result_null(C)], except that it
6337** also associates the host-language pointer P or type T with that
6338** NULL value such that the pointer can be retrieved within an
6339** [application-defined SQL function] using [sqlite3_value_pointer()].
6340** ^If the D parameter is not NULL, then it is a pointer to a destructor
6341** for the P parameter. ^SQLite invokes D with P as its only argument
6342** when SQLite is finished with P. The T parameter should be a static
6343** string and preferably a string literal. The sqlite3_result_pointer()
6344** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
6345**
6346** If these routines are called from within the different thread
6347** than the one containing the application-defined function that received
6348** the [sqlite3_context] pointer, the results are undefined.
6349*/
6350SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
6351SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
6352 sqlite3_uint64,void(*)(void*));
6353SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
6354SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
6355SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
6356SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
6357SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
6358SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
6359SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
6360SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
6361SQLITE_API void sqlite3_result_null(sqlite3_context*);
6362SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
6363SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
6364 void(*)(void*), unsigned char encoding);
6365SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
6366SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
6367SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
6368SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
6369SQLITE_API void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
6370SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
6371SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
6372
6373
6374/*
6375** CAPI3REF: Setting The Subtype Of An SQL Function
6376** METHOD: sqlite3_context
6377**
6378** The sqlite3_result_subtype(C,T) function causes the subtype of
6379** the result from the [application-defined SQL function] with
6380** [sqlite3_context] C to be the value T. Only the lower 8 bits
6381** of the subtype T are preserved in current versions of SQLite;
6382** higher order bits are discarded.
6383** The number of subtype bytes preserved by SQLite might increase
6384** in future releases of SQLite.
6385**
6386** Every [application-defined SQL function] that invokes this interface
6387** should include the [SQLITE_RESULT_SUBTYPE] property in its
6388** text encoding argument when the SQL function is
6389** [sqlite3_create_function|registered]. If the [SQLITE_RESULT_SUBTYPE]
6390** property is omitted from the function that invokes sqlite3_result_subtype(),
6391** then in some cases the sqlite3_result_subtype() might fail to set
6392** the result subtype.
6393**
6394** If SQLite is compiled with -DSQLITE_STRICT_SUBTYPE=1, then any
6395** SQL function that invokes the sqlite3_result_subtype() interface
6396** and that does not have the SQLITE_RESULT_SUBTYPE property will raise
6397** an error. Future versions of SQLite might enable -DSQLITE_STRICT_SUBTYPE=1
6398** by default.
6399*/
6400SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int);
6401
6402/*
6403** CAPI3REF: Define New Collating Sequences
6404** METHOD: sqlite3
6405**
6406** ^These functions add, remove, or modify a [collation] associated
6407** with the [database connection] specified as the first argument.
6408**
6409** ^The name of the collation is a UTF-8 string
6410** for sqlite3_create_collation() and sqlite3_create_collation_v2()
6411** and a UTF-16 string in native byte order for sqlite3_create_collation16().
6412** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
6413** considered to be the same name.
6414**
6415** ^(The third argument (eTextRep) must be one of the constants:
6416** <ul>
6417** <li> [SQLITE_UTF8],
6418** <li> [SQLITE_UTF16LE],
6419** <li> [SQLITE_UTF16BE],
6420** <li> [SQLITE_UTF16], or
6421** <li> [SQLITE_UTF16_ALIGNED].
6422** </ul>)^
6423** ^The eTextRep argument determines the encoding of strings passed
6424** to the collating function callback, xCompare.
6425** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
6426** force strings to be UTF16 with native byte order.
6427** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
6428** on an even byte address.
6429**
6430** ^The fourth argument, pArg, is an application data pointer that is passed
6431** through as the first argument to the collating function callback.
6432**
6433** ^The fifth argument, xCompare, is a pointer to the collating function.
6434** ^Multiple collating functions can be registered using the same name but
6435** with different eTextRep parameters and SQLite will use whichever
6436** function requires the least amount of data transformation.
6437** ^If the xCompare argument is NULL then the collating function is
6438** deleted. ^When all collating functions having the same name are deleted,
6439** that collation is no longer usable.
6440**
6441** ^The collating function callback is invoked with a copy of the pArg
6442** application data pointer and with two strings in the encoding specified
6443** by the eTextRep argument. The two integer parameters to the collating
6444** function callback are the length of the two strings, in bytes. The collating
6445** function must return an integer that is negative, zero, or positive
6446** if the first string is less than, equal to, or greater than the second,
6447** respectively. A collating function must always return the same answer
6448** given the same inputs. If two or more collating functions are registered
6449** to the same collation name (using different eTextRep values) then all
6450** must give an equivalent answer when invoked with equivalent strings.
6451** The collating function must obey the following properties for all
6452** strings A, B, and C:
6453**
6454** <ol>
6455** <li> If A==B then B==A.
6456** <li> If A==B and B==C then A==C.
6457** <li> If A&lt;B THEN B&gt;A.
6458** <li> If A&lt;B and B&lt;C then A&lt;C.
6459** </ol>
6460**
6461** If a collating function fails any of the above constraints and that
6462** collating function is registered and used, then the behavior of SQLite
6463** is undefined.
6464**
6465** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
6466** with the addition that the xDestroy callback is invoked on pArg when
6467** the collating function is deleted.
6468** ^Collating functions are deleted when they are overridden by later
6469** calls to the collation creation functions or when the
6470** [database connection] is closed using [sqlite3_close()].
6471**
6472** ^The xDestroy callback is <u>not</u> called if the
6473** sqlite3_create_collation_v2() function fails. Applications that invoke
6474** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
6475** check the return code and dispose of the application data pointer
6476** themselves rather than expecting SQLite to deal with it for them.
6477** This is different from every other SQLite interface. The inconsistency
6478** is unfortunate but cannot be changed without breaking backwards
6479** compatibility.
6480**
6481** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
6482*/
6483SQLITE_API int sqlite3_create_collation(
6484 sqlite3*,
6485 const char *zName,
6486 int eTextRep,
6487 void *pArg,
6488 int(*xCompare)(void*,int,const void*,int,const void*)
6489);
6490SQLITE_API int sqlite3_create_collation_v2(
6491 sqlite3*,
6492 const char *zName,
6493 int eTextRep,
6494 void *pArg,
6495 int(*xCompare)(void*,int,const void*,int,const void*),
6496 void(*xDestroy)(void*)
6497);
6498SQLITE_API int sqlite3_create_collation16(
6499 sqlite3*,
6500 const void *zName,
6501 int eTextRep,
6502 void *pArg,
6503 int(*xCompare)(void*,int,const void*,int,const void*)
6504);
6505
6506/*
6507** CAPI3REF: Collation Needed Callbacks
6508** METHOD: sqlite3
6509**
6510** ^To avoid having to register all collation sequences before a database
6511** can be used, a single callback function may be registered with the
6512** [database connection] to be invoked whenever an undefined collation
6513** sequence is required.
6514**
6515** ^If the function is registered using the sqlite3_collation_needed() API,
6516** then it is passed the names of undefined collation sequences as strings
6517** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
6518** the names are passed as UTF-16 in machine native byte order.
6519** ^A call to either function replaces the existing collation-needed callback.
6520**
6521** ^(When the callback is invoked, the first argument passed is a copy
6522** of the second argument to sqlite3_collation_needed() or
6523** sqlite3_collation_needed16(). The second argument is the database
6524** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
6525** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
6526** sequence function required. The fourth parameter is the name of the
6527** required collation sequence.)^
6528**
6529** The callback function should register the desired collation using
6530** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
6531** [sqlite3_create_collation_v2()].
6532*/
6533SQLITE_API int sqlite3_collation_needed(
6534 sqlite3*,
6535 void*,
6536 void(*)(void*,sqlite3*,int eTextRep,const char*)
6537);
6538SQLITE_API int sqlite3_collation_needed16(
6539 sqlite3*,
6540 void*,
6541 void(*)(void*,sqlite3*,int eTextRep,const void*)
6542);
6543
6544#ifdef SQLITE_ENABLE_CEROD
6545/*
6546** Specify the activation key for a CEROD database. Unless
6547** activated, none of the CEROD routines will work.
6548*/
6549SQLITE_API void sqlite3_activate_cerod(
6550 const char *zPassPhrase /* Activation phrase */
6551);
6552#endif
6553
6554/*
6555** CAPI3REF: Suspend Execution For A Short Time
6556**
6557** The sqlite3_sleep() function causes the current thread to suspend execution
6558** for at least a number of milliseconds specified in its parameter.
6559**
6560** If the operating system does not support sleep requests with
6561** millisecond time resolution, then the time will be rounded up to
6562** the nearest second. The number of milliseconds of sleep actually
6563** requested from the operating system is returned.
6564**
6565** ^SQLite implements this interface by calling the xSleep()
6566** method of the default [sqlite3_vfs] object. If the xSleep() method
6567** of the default VFS is not implemented correctly, or not implemented at
6568** all, then the behavior of sqlite3_sleep() may deviate from the description
6569** in the previous paragraphs.
6570**
6571** If a negative argument is passed to sqlite3_sleep() the results vary by
6572** VFS and operating system. Some system treat a negative argument as an
6573** instruction to sleep forever. Others understand it to mean do not sleep
6574** at all. ^In SQLite version 3.42.0 and later, a negative
6575** argument passed into sqlite3_sleep() is changed to zero before it is relayed
6576** down into the xSleep method of the VFS.
6577*/
6578SQLITE_API int sqlite3_sleep(int);
6579
6580/*
6581** CAPI3REF: Name Of The Folder Holding Temporary Files
6582**
6583** ^(If this global variable is made to point to a string which is
6584** the name of a folder (a.k.a. directory), then all temporary files
6585** created by SQLite when using a built-in [sqlite3_vfs | VFS]
6586** will be placed in that directory.)^ ^If this variable
6587** is a NULL pointer, then SQLite performs a search for an appropriate
6588** temporary file directory.
6589**
6590** Applications are strongly discouraged from using this global variable.
6591** It is required to set a temporary folder on Windows Runtime (WinRT).
6592** But for all other platforms, it is highly recommended that applications
6593** neither read nor write this variable. This global variable is a relic
6594** that exists for backwards compatibility of legacy applications and should
6595** be avoided in new projects.
6596**
6597** It is not safe to read or modify this variable in more than one
6598** thread at a time. It is not safe to read or modify this variable
6599** if a [database connection] is being used at the same time in a separate
6600** thread.
6601** It is intended that this variable be set once
6602** as part of process initialization and before any SQLite interface
6603** routines have been called and that this variable remain unchanged
6604** thereafter.
6605**
6606** ^The [temp_store_directory pragma] may modify this variable and cause
6607** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
6608** the [temp_store_directory pragma] always assumes that any string
6609** that this variable points to is held in memory obtained from
6610** [sqlite3_malloc] and the pragma may attempt to free that memory
6611** using [sqlite3_free].
6612** Hence, if this variable is modified directly, either it should be
6613** made NULL or made to point to memory obtained from [sqlite3_malloc]
6614** or else the use of the [temp_store_directory pragma] should be avoided.
6615** Except when requested by the [temp_store_directory pragma], SQLite
6616** does not free the memory that sqlite3_temp_directory points to. If
6617** the application wants that memory to be freed, it must do
6618** so itself, taking care to only do so after all [database connection]
6619** objects have been destroyed.
6620**
6621** <b>Note to Windows Runtime users:</b> The temporary directory must be set
6622** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various
6623** features that require the use of temporary files may fail. Here is an
6624** example of how to do this using C++ with the Windows Runtime:
6625**
6626** <blockquote><pre>
6627** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
6628** &nbsp; TemporaryFolder->Path->Data();
6629** char zPathBuf&#91;MAX_PATH + 1&#93;;
6630** memset(zPathBuf, 0, sizeof(zPathBuf));
6631** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
6632** &nbsp; NULL, NULL);
6633** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
6634** </pre></blockquote>
6635*/
6636SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
6637
6638/*
6639** CAPI3REF: Name Of The Folder Holding Database Files
6640**
6641** ^(If this global variable is made to point to a string which is
6642** the name of a folder (a.k.a. directory), then all database files
6643** specified with a relative pathname and created or accessed by
6644** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
6645** to be relative to that directory.)^ ^If this variable is a NULL
6646** pointer, then SQLite assumes that all database files specified
6647** with a relative pathname are relative to the current directory
6648** for the process. Only the windows VFS makes use of this global
6649** variable; it is ignored by the unix VFS.
6650**
6651** Changing the value of this variable while a database connection is
6652** open can result in a corrupt database.
6653**
6654** It is not safe to read or modify this variable in more than one
6655** thread at a time. It is not safe to read or modify this variable
6656** if a [database connection] is being used at the same time in a separate
6657** thread.
6658** It is intended that this variable be set once
6659** as part of process initialization and before any SQLite interface
6660** routines have been called and that this variable remain unchanged
6661** thereafter.
6662**
6663** ^The [data_store_directory pragma] may modify this variable and cause
6664** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
6665** the [data_store_directory pragma] always assumes that any string
6666** that this variable points to is held in memory obtained from
6667** [sqlite3_malloc] and the pragma may attempt to free that memory
6668** using [sqlite3_free].
6669** Hence, if this variable is modified directly, either it should be
6670** made NULL or made to point to memory obtained from [sqlite3_malloc]
6671** or else the use of the [data_store_directory pragma] should be avoided.
6672*/
6673SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
6674
6675/*
6676** CAPI3REF: Win32 Specific Interface
6677**
6678** These interfaces are available only on Windows. The
6679** [sqlite3_win32_set_directory] interface is used to set the value associated
6680** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to
6681** zValue, depending on the value of the type parameter. The zValue parameter
6682** should be NULL to cause the previous value to be freed via [sqlite3_free];
6683** a non-NULL value will be copied into memory obtained from [sqlite3_malloc]
6684** prior to being used. The [sqlite3_win32_set_directory] interface returns
6685** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported,
6686** or [SQLITE_NOMEM] if memory could not be allocated. The value of the
6687** [sqlite3_data_directory] variable is intended to act as a replacement for
6688** the current directory on the sub-platforms of Win32 where that concept is
6689** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and
6690** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the
6691** sqlite3_win32_set_directory interface except the string parameter must be
6692** UTF-8 or UTF-16, respectively.
6693*/
6694SQLITE_API int sqlite3_win32_set_directory(
6695 unsigned long type, /* Identifier for directory being set or reset */
6696 void *zValue /* New value for directory being set or reset */
6697);
6698SQLITE_API int sqlite3_win32_set_directory8(unsigned long type, const char *zValue);
6699SQLITE_API int sqlite3_win32_set_directory16(unsigned long type, const void *zValue);
6700
6701/*
6702** CAPI3REF: Win32 Directory Types
6703**
6704** These macros are only available on Windows. They define the allowed values
6705** for the type argument to the [sqlite3_win32_set_directory] interface.
6706*/
6707#define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1
6708#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2
6709
6710/*
6711** CAPI3REF: Test For Auto-Commit Mode
6712** KEYWORDS: {autocommit mode}
6713** METHOD: sqlite3
6714**
6715** ^The sqlite3_get_autocommit() interface returns non-zero or
6716** zero if the given database connection is or is not in autocommit mode,
6717** respectively. ^Autocommit mode is on by default.
6718** ^Autocommit mode is disabled by a [BEGIN] statement.
6719** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
6720**
6721** If certain kinds of errors occur on a statement within a multi-statement
6722** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
6723** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
6724** transaction might be rolled back automatically. The only way to
6725** find out whether SQLite automatically rolled back the transaction after
6726** an error is to use this function.
6727**
6728** If another thread changes the autocommit status of the database
6729** connection while this routine is running, then the return value
6730** is undefined.
6731*/
6732SQLITE_API int sqlite3_get_autocommit(sqlite3*);
6733
6734/*
6735** CAPI3REF: Find The Database Handle Of A Prepared Statement
6736** METHOD: sqlite3_stmt
6737**
6738** ^The sqlite3_db_handle interface returns the [database connection] handle
6739** to which a [prepared statement] belongs. ^The [database connection]
6740** returned by sqlite3_db_handle is the same [database connection]
6741** that was the first argument
6742** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
6743** create the statement in the first place.
6744*/
6745SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
6746
6747/*
6748** CAPI3REF: Return The Schema Name For A Database Connection
6749** METHOD: sqlite3
6750**
6751** ^The sqlite3_db_name(D,N) interface returns a pointer to the schema name
6752** for the N-th database on database connection D, or a NULL pointer of N is
6753** out of range. An N value of 0 means the main database file. An N of 1 is
6754** the "temp" schema. Larger values of N correspond to various ATTACH-ed
6755** databases.
6756**
6757** Space to hold the string that is returned by sqlite3_db_name() is managed
6758** by SQLite itself. The string might be deallocated by any operation that
6759** changes the schema, including [ATTACH] or [DETACH] or calls to
6760** [sqlite3_serialize()] or [sqlite3_deserialize()], even operations that
6761** occur on a different thread. Applications that need to
6762** remember the string long-term should make their own copy. Applications that
6763** are accessing the same database connection simultaneously on multiple
6764** threads should mutex-protect calls to this API and should make their own
6765** private copy of the result prior to releasing the mutex.
6766*/
6767SQLITE_API const char *sqlite3_db_name(sqlite3 *db, int N);
6768
6769/*
6770** CAPI3REF: Return The Filename For A Database Connection
6771** METHOD: sqlite3
6772**
6773** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename
6774** associated with database N of connection D.
6775** ^If there is no attached database N on the database
6776** connection D, or if database N is a temporary or in-memory database, then
6777** this function will return either a NULL pointer or an empty string.
6778**
6779** ^The string value returned by this routine is owned and managed by
6780** the database connection. ^The value will be valid until the database N
6781** is [DETACH]-ed or until the database connection closes.
6782**
6783** ^The filename returned by this function is the output of the
6784** xFullPathname method of the [VFS]. ^In other words, the filename
6785** will be an absolute pathname, even if the filename used
6786** to open the database originally was a URI or relative pathname.
6787**
6788** If the filename pointer returned by this routine is not NULL, then it
6789** can be used as the filename input parameter to these routines:
6790** <ul>
6791** <li> [sqlite3_uri_parameter()]
6792** <li> [sqlite3_uri_boolean()]
6793** <li> [sqlite3_uri_int64()]
6794** <li> [sqlite3_filename_database()]
6795** <li> [sqlite3_filename_journal()]
6796** <li> [sqlite3_filename_wal()]
6797** </ul>
6798*/
6799SQLITE_API sqlite3_filename sqlite3_db_filename(sqlite3 *db, const char *zDbName);
6800
6801/*
6802** CAPI3REF: Determine if a database is read-only
6803** METHOD: sqlite3
6804**
6805** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
6806** of connection D is read-only, 0 if it is read/write, or -1 if N is not
6807** the name of a database on connection D.
6808*/
6809SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
6810
6811/*
6812** CAPI3REF: Determine the transaction state of a database
6813** METHOD: sqlite3
6814**
6815** ^The sqlite3_txn_state(D,S) interface returns the current
6816** [transaction state] of schema S in database connection D. ^If S is NULL,
6817** then the highest transaction state of any schema on database connection D
6818** is returned. Transaction states are (in order of lowest to highest):
6819** <ol>
6820** <li value="0"> SQLITE_TXN_NONE
6821** <li value="1"> SQLITE_TXN_READ
6822** <li value="2"> SQLITE_TXN_WRITE
6823** </ol>
6824** ^If the S argument to sqlite3_txn_state(D,S) is not the name of
6825** a valid schema, then -1 is returned.
6826*/
6827SQLITE_API int sqlite3_txn_state(sqlite3*,const char *zSchema);
6828
6829/*
6830** CAPI3REF: Allowed return values from sqlite3_txn_state()
6831** KEYWORDS: {transaction state}
6832**
6833** These constants define the current transaction state of a database file.
6834** ^The [sqlite3_txn_state(D,S)] interface returns one of these
6835** constants in order to describe the transaction state of schema S
6836** in [database connection] D.
6837**
6838** <dl>
6839** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt>
6840** <dd>The SQLITE_TXN_NONE state means that no transaction is currently
6841** pending.</dd>
6842**
6843** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt>
6844** <dd>The SQLITE_TXN_READ state means that the database is currently
6845** in a read transaction. Content has been read from the database file
6846** but nothing in the database file has changed. The transaction state
6847** will advanced to SQLITE_TXN_WRITE if any changes occur and there are
6848** no other conflicting concurrent write transactions. The transaction
6849** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or
6850** [COMMIT].</dd>
6851**
6852** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt>
6853** <dd>The SQLITE_TXN_WRITE state means that the database is currently
6854** in a write transaction. Content has been written to the database file
6855** but has not yet committed. The transaction state will change to
6856** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd>
6857*/
6858#define SQLITE_TXN_NONE 0
6859#define SQLITE_TXN_READ 1
6860#define SQLITE_TXN_WRITE 2
6861
6862/*
6863** CAPI3REF: Find the next prepared statement
6864** METHOD: sqlite3
6865**
6866** ^This interface returns a pointer to the next [prepared statement] after
6867** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
6868** then this interface returns a pointer to the first prepared statement
6869** associated with the database connection pDb. ^If no prepared statement
6870** satisfies the conditions of this routine, it returns NULL.
6871**
6872** The [database connection] pointer D in a call to
6873** [sqlite3_next_stmt(D,S)] must refer to an open database
6874** connection and in particular must not be a NULL pointer.
6875*/
6876SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
6877
6878/*
6879** CAPI3REF: Commit And Rollback Notification Callbacks
6880** METHOD: sqlite3
6881**
6882** ^The sqlite3_commit_hook() interface registers a callback
6883** function to be invoked whenever a transaction is [COMMIT | committed].
6884** ^Any callback set by a previous call to sqlite3_commit_hook()
6885** for the same database connection is overridden.
6886** ^The sqlite3_rollback_hook() interface registers a callback
6887** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
6888** ^Any callback set by a previous call to sqlite3_rollback_hook()
6889** for the same database connection is overridden.
6890** ^The pArg argument is passed through to the callback.
6891** ^If the callback on a commit hook function returns non-zero,
6892** then the commit is converted into a rollback.
6893**
6894** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
6895** return the P argument from the previous call of the same function
6896** on the same [database connection] D, or NULL for
6897** the first call for each function on D.
6898**
6899** The commit and rollback hook callbacks are not reentrant.
6900** The callback implementation must not do anything that will modify
6901** the database connection that invoked the callback. Any actions
6902** to modify the database connection must be deferred until after the
6903** completion of the [sqlite3_step()] call that triggered the commit
6904** or rollback hook in the first place.
6905** Note that running any other SQL statements, including SELECT statements,
6906** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
6907** the database connections for the meaning of "modify" in this paragraph.
6908**
6909** ^Registering a NULL function disables the callback.
6910**
6911** ^When the commit hook callback routine returns zero, the [COMMIT]
6912** operation is allowed to continue normally. ^If the commit hook
6913** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
6914** ^The rollback hook is invoked on a rollback that results from a commit
6915** hook returning non-zero, just as it would be with any other rollback.
6916**
6917** ^For the purposes of this API, a transaction is said to have been
6918** rolled back if an explicit "ROLLBACK" statement is executed, or
6919** an error or constraint causes an implicit rollback to occur.
6920** ^The rollback callback is not invoked if a transaction is
6921** automatically rolled back because the database connection is closed.
6922**
6923** See also the [sqlite3_update_hook()] interface.
6924*/
6925SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
6926SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
6927
6928/*
6929** CAPI3REF: Autovacuum Compaction Amount Callback
6930** METHOD: sqlite3
6931**
6932** ^The sqlite3_autovacuum_pages(D,C,P,X) interface registers a callback
6933** function C that is invoked prior to each autovacuum of the database
6934** file. ^The callback is passed a copy of the generic data pointer (P),
6935** the schema-name of the attached database that is being autovacuumed,
6936** the size of the database file in pages, the number of free pages,
6937** and the number of bytes per page, respectively. The callback should
6938** return the number of free pages that should be removed by the
6939** autovacuum. ^If the callback returns zero, then no autovacuum happens.
6940** ^If the value returned is greater than or equal to the number of
6941** free pages, then a complete autovacuum happens.
6942**
6943** <p>^If there are multiple ATTACH-ed database files that are being
6944** modified as part of a transaction commit, then the autovacuum pages
6945** callback is invoked separately for each file.
6946**
6947** <p><b>The callback is not reentrant.</b> The callback function should
6948** not attempt to invoke any other SQLite interface. If it does, bad
6949** things may happen, including segmentation faults and corrupt database
6950** files. The callback function should be a simple function that
6951** does some arithmetic on its input parameters and returns a result.
6952**
6953** ^The X parameter to sqlite3_autovacuum_pages(D,C,P,X) is an optional
6954** destructor for the P parameter. ^If X is not NULL, then X(P) is
6955** invoked whenever the database connection closes or when the callback
6956** is overwritten by another invocation of sqlite3_autovacuum_pages().
6957**
6958** <p>^There is only one autovacuum pages callback per database connection.
6959** ^Each call to the sqlite3_autovacuum_pages() interface overrides all
6960** previous invocations for that database connection. ^If the callback
6961** argument (C) to sqlite3_autovacuum_pages(D,C,P,X) is a NULL pointer,
6962** then the autovacuum steps callback is canceled. The return value
6963** from sqlite3_autovacuum_pages() is normally SQLITE_OK, but might
6964** be some other error code if something goes wrong. The current
6965** implementation will only return SQLITE_OK or SQLITE_MISUSE, but other
6966** return codes might be added in future releases.
6967**
6968** <p>If no autovacuum pages callback is specified (the usual case) or
6969** a NULL pointer is provided for the callback,
6970** then the default behavior is to vacuum all free pages. So, in other
6971** words, the default behavior is the same as if the callback function
6972** were something like this:
6973**
6974** <blockquote><pre>
6975** &nbsp; unsigned int demonstration_autovac_pages_callback(
6976** &nbsp; void *pClientData,
6977** &nbsp; const char *zSchema,
6978** &nbsp; unsigned int nDbPage,
6979** &nbsp; unsigned int nFreePage,
6980** &nbsp; unsigned int nBytePerPage
6981** &nbsp; ){
6982** &nbsp; return nFreePage;
6983** &nbsp; }
6984** </pre></blockquote>
6985*/
6986SQLITE_API int sqlite3_autovacuum_pages(
6987 sqlite3 *db,
6988 unsigned int(*)(void*,const char*,unsigned int,unsigned int,unsigned int),
6989 void*,
6990 void(*)(void*)
6991);
6992
6993
6994/*
6995** CAPI3REF: Data Change Notification Callbacks
6996** METHOD: sqlite3
6997**
6998** ^The sqlite3_update_hook() interface registers a callback function
6999** with the [database connection] identified by the first argument
7000** to be invoked whenever a row is updated, inserted or deleted in
7001** a [rowid table].
7002** ^Any callback set by a previous call to this function
7003** for the same database connection is overridden.
7004**
7005** ^The second argument is a pointer to the function to invoke when a
7006** row is updated, inserted or deleted in a rowid table.
7007** ^The first argument to the callback is a copy of the third argument
7008** to sqlite3_update_hook().
7009** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
7010** or [SQLITE_UPDATE], depending on the operation that caused the callback
7011** to be invoked.
7012** ^The third and fourth arguments to the callback contain pointers to the
7013** database and table name containing the affected row.
7014** ^The final callback parameter is the [rowid] of the row.
7015** ^In the case of an update, this is the [rowid] after the update takes place.
7016**
7017** ^(The update hook is not invoked when internal system tables are
7018** modified (i.e. sqlite_sequence).)^
7019** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
7020**
7021** ^In the current implementation, the update hook
7022** is not invoked when conflicting rows are deleted because of an
7023** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
7024** invoked when rows are deleted using the [truncate optimization].
7025** The exceptions defined in this paragraph might change in a future
7026** release of SQLite.
7027**
7028** Whether the update hook is invoked before or after the
7029** corresponding change is currently unspecified and may differ
7030** depending on the type of change. Do not rely on the order of the
7031** hook call with regards to the final result of the operation which
7032** triggers the hook.
7033**
7034** The update hook implementation must not do anything that will modify
7035** the database connection that invoked the update hook. Any actions
7036** to modify the database connection must be deferred until after the
7037** completion of the [sqlite3_step()] call that triggered the update hook.
7038** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
7039** database connections for the meaning of "modify" in this paragraph.
7040**
7041** ^The sqlite3_update_hook(D,C,P) function
7042** returns the P argument from the previous call
7043** on the same [database connection] D, or NULL for
7044** the first call on D.
7045**
7046** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
7047** and [sqlite3_preupdate_hook()] interfaces.
7048*/
7049SQLITE_API void *sqlite3_update_hook(
7050 sqlite3*,
7051 void(*)(void *,int ,char const *,char const *,sqlite3_int64),
7052 void*
7053);
7054
7055/*
7056** CAPI3REF: Enable Or Disable Shared Pager Cache
7057**
7058** ^(This routine enables or disables the sharing of the database cache
7059** and schema data structures between [database connection | connections]
7060** to the same database. Sharing is enabled if the argument is true
7061** and disabled if the argument is false.)^
7062**
7063** This interface is omitted if SQLite is compiled with
7064** [-DSQLITE_OMIT_SHARED_CACHE]. The [-DSQLITE_OMIT_SHARED_CACHE]
7065** compile-time option is recommended because the
7066** [use of shared cache mode is discouraged].
7067**
7068** ^Cache sharing is enabled and disabled for an entire process.
7069** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
7070** In prior versions of SQLite,
7071** sharing was enabled or disabled for each thread separately.
7072**
7073** ^(The cache sharing mode set by this interface effects all subsequent
7074** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
7075** Existing database connections continue to use the sharing mode
7076** that was in effect at the time they were opened.)^
7077**
7078** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
7079** successfully. An [error code] is returned otherwise.)^
7080**
7081** ^Shared cache is disabled by default. It is recommended that it stay
7082** that way. In other words, do not use this routine. This interface
7083** continues to be provided for historical compatibility, but its use is
7084** discouraged. Any use of shared cache is discouraged. If shared cache
7085** must be used, it is recommended that shared cache only be enabled for
7086** individual database connections using the [sqlite3_open_v2()] interface
7087** with the [SQLITE_OPEN_SHAREDCACHE] flag.
7088**
7089** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
7090** and will always return SQLITE_MISUSE. On those systems,
7091** shared cache mode should be enabled per-database connection via
7092** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
7093**
7094** This interface is threadsafe on processors where writing a
7095** 32-bit integer is atomic.
7096**
7097** See Also: [SQLite Shared-Cache Mode]
7098*/
7099SQLITE_API int sqlite3_enable_shared_cache(int);
7100
7101/*
7102** CAPI3REF: Attempt To Free Heap Memory
7103**
7104** ^The sqlite3_release_memory() interface attempts to free N bytes
7105** of heap memory by deallocating non-essential memory allocations
7106** held by the database library. Memory used to cache database
7107** pages to improve performance is an example of non-essential memory.
7108** ^sqlite3_release_memory() returns the number of bytes actually freed,
7109** which might be more or less than the amount requested.
7110** ^The sqlite3_release_memory() routine is a no-op returning zero
7111** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
7112**
7113** See also: [sqlite3_db_release_memory()]
7114*/
7115SQLITE_API int sqlite3_release_memory(int);
7116
7117/*
7118** CAPI3REF: Free Memory Used By A Database Connection
7119** METHOD: sqlite3
7120**
7121** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
7122** memory as possible from database connection D. Unlike the
7123** [sqlite3_release_memory()] interface, this interface is in effect even
7124** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
7125** omitted.
7126**
7127** See also: [sqlite3_release_memory()]
7128*/
7129SQLITE_API int sqlite3_db_release_memory(sqlite3*);
7130
7131/*
7132** CAPI3REF: Impose A Limit On Heap Size
7133**
7134** These interfaces impose limits on the amount of heap memory that will be
7135** by all database connections within a single process.
7136**
7137** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
7138** soft limit on the amount of heap memory that may be allocated by SQLite.
7139** ^SQLite strives to keep heap memory utilization below the soft heap
7140** limit by reducing the number of pages held in the page cache
7141** as heap memory usages approaches the limit.
7142** ^The soft heap limit is "soft" because even though SQLite strives to stay
7143** below the limit, it will exceed the limit rather than generate
7144** an [SQLITE_NOMEM] error. In other words, the soft heap limit
7145** is advisory only.
7146**
7147** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of
7148** N bytes on the amount of memory that will be allocated. ^The
7149** sqlite3_hard_heap_limit64(N) interface is similar to
7150** sqlite3_soft_heap_limit64(N) except that memory allocations will fail
7151** when the hard heap limit is reached.
7152**
7153** ^The return value from both sqlite3_soft_heap_limit64() and
7154** sqlite3_hard_heap_limit64() is the size of
7155** the heap limit prior to the call, or negative in the case of an
7156** error. ^If the argument N is negative
7157** then no change is made to the heap limit. Hence, the current
7158** size of heap limits can be determined by invoking
7159** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1).
7160**
7161** ^Setting the heap limits to zero disables the heap limiter mechanism.
7162**
7163** ^The soft heap limit may not be greater than the hard heap limit.
7164** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N)
7165** is invoked with a value of N that is greater than the hard heap limit,
7166** the soft heap limit is set to the value of the hard heap limit.
7167** ^The soft heap limit is automatically enabled whenever the hard heap
7168** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and
7169** the soft heap limit is outside the range of 1..N, then the soft heap
7170** limit is set to N. ^Invoking sqlite3_soft_heap_limit64(0) when the
7171** hard heap limit is enabled makes the soft heap limit equal to the
7172** hard heap limit.
7173**
7174** The memory allocation limits can also be adjusted using
7175** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit].
7176**
7177** ^(The heap limits are not enforced in the current implementation
7178** if one or more of following conditions are true:
7179**
7180** <ul>
7181** <li> The limit value is set to zero.
7182** <li> Memory accounting is disabled using a combination of the
7183** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
7184** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
7185** <li> An alternative page cache implementation is specified using
7186** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
7187** <li> The page cache allocates from its own memory pool supplied
7188** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
7189** from the heap.
7190** </ul>)^
7191**
7192** The circumstances under which SQLite will enforce the heap limits may
7193** changes in future releases of SQLite.
7194*/
7195SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
7196SQLITE_API sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N);
7197
7198/*
7199** CAPI3REF: Deprecated Soft Heap Limit Interface
7200** DEPRECATED
7201**
7202** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
7203** interface. This routine is provided for historical compatibility
7204** only. All new applications should use the
7205** [sqlite3_soft_heap_limit64()] interface rather than this one.
7206*/
7207SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
7208
7209
7210/*
7211** CAPI3REF: Extract Metadata About A Column Of A Table
7212** METHOD: sqlite3
7213**
7214** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
7215** information about column C of table T in database D
7216** on [database connection] X.)^ ^The sqlite3_table_column_metadata()
7217** interface returns SQLITE_OK and fills in the non-NULL pointers in
7218** the final five arguments with appropriate values if the specified
7219** column exists. ^The sqlite3_table_column_metadata() interface returns
7220** SQLITE_ERROR if the specified column does not exist.
7221** ^If the column-name parameter to sqlite3_table_column_metadata() is a
7222** NULL pointer, then this routine simply checks for the existence of the
7223** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
7224** does not. If the table name parameter T in a call to
7225** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
7226** undefined behavior.
7227**
7228** ^The column is identified by the second, third and fourth parameters to
7229** this function. ^(The second parameter is either the name of the database
7230** (i.e. "main", "temp", or an attached database) containing the specified
7231** table or NULL.)^ ^If it is NULL, then all attached databases are searched
7232** for the table using the same algorithm used by the database engine to
7233** resolve unqualified table references.
7234**
7235** ^The third and fourth parameters to this function are the table and column
7236** name of the desired column, respectively.
7237**
7238** ^Metadata is returned by writing to the memory locations passed as the 5th
7239** and subsequent parameters to this function. ^Any of these arguments may be
7240** NULL, in which case the corresponding element of metadata is omitted.
7241**
7242** ^(<blockquote>
7243** <table border="1">
7244** <tr><th> Parameter <th> Output<br>Type <th> Description
7245**
7246** <tr><td> 5th <td> const char* <td> Data type
7247** <tr><td> 6th <td> const char* <td> Name of default collation sequence
7248** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
7249** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
7250** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
7251** </table>
7252** </blockquote>)^
7253**
7254** ^The memory pointed to by the character pointers returned for the
7255** declaration type and collation sequence is valid until the next
7256** call to any SQLite API function.
7257**
7258** ^If the specified table is actually a view, an [error code] is returned.
7259**
7260** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
7261** is not a [WITHOUT ROWID] table and an
7262** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
7263** parameters are set for the explicitly declared column. ^(If there is no
7264** [INTEGER PRIMARY KEY] column, then the outputs
7265** for the [rowid] are set as follows:
7266**
7267** <pre>
7268** data type: "INTEGER"
7269** collation sequence: "BINARY"
7270** not null: 0
7271** primary key: 1
7272** auto increment: 0
7273** </pre>)^
7274**
7275** ^This function causes all database schemas to be read from disk and
7276** parsed, if that has not already been done, and returns an error if
7277** any errors are encountered while loading the schema.
7278*/
7279SQLITE_API int sqlite3_table_column_metadata(
7280 sqlite3 *db, /* Connection handle */
7281 const char *zDbName, /* Database name or NULL */
7282 const char *zTableName, /* Table name */
7283 const char *zColumnName, /* Column name */
7284 char const **pzDataType, /* OUTPUT: Declared data type */
7285 char const **pzCollSeq, /* OUTPUT: Collation sequence name */
7286 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
7287 int *pPrimaryKey, /* OUTPUT: True if column part of PK */
7288 int *pAutoinc /* OUTPUT: True if column is auto-increment */
7289);
7290
7291/*
7292** CAPI3REF: Load An Extension
7293** METHOD: sqlite3
7294**
7295** ^This interface loads an SQLite extension library from the named file.
7296**
7297** ^The sqlite3_load_extension() interface attempts to load an
7298** [SQLite extension] library contained in the file zFile. If
7299** the file cannot be loaded directly, attempts are made to load
7300** with various operating-system specific extensions added.
7301** So for example, if "samplelib" cannot be loaded, then names like
7302** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
7303** be tried also.
7304**
7305** ^The entry point is zProc.
7306** ^(zProc may be 0, in which case SQLite will try to come up with an
7307** entry point name on its own. It first tries "sqlite3_extension_init".
7308** If that does not work, it constructs a name "sqlite3_X_init" where the
7309** X is consists of the lower-case equivalent of all ASCII alphabetic
7310** characters in the filename from the last "/" to the first following
7311** "." and omitting any initial "lib".)^
7312** ^The sqlite3_load_extension() interface returns
7313** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
7314** ^If an error occurs and pzErrMsg is not 0, then the
7315** [sqlite3_load_extension()] interface shall attempt to
7316** fill *pzErrMsg with error message text stored in memory
7317** obtained from [sqlite3_malloc()]. The calling function
7318** should free this memory by calling [sqlite3_free()].
7319**
7320** ^Extension loading must be enabled using
7321** [sqlite3_enable_load_extension()] or
7322** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
7323** prior to calling this API,
7324** otherwise an error will be returned.
7325**
7326** <b>Security warning:</b> It is recommended that the
7327** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
7328** interface. The use of the [sqlite3_enable_load_extension()] interface
7329** should be avoided. This will keep the SQL function [load_extension()]
7330** disabled and prevent SQL injections from giving attackers
7331** access to extension loading capabilities.
7332**
7333** See also the [load_extension() SQL function].
7334*/
7335SQLITE_API int sqlite3_load_extension(
7336 sqlite3 *db, /* Load the extension into this database connection */
7337 const char *zFile, /* Name of the shared library containing extension */
7338 const char *zProc, /* Entry point. Derived from zFile if 0 */
7339 char **pzErrMsg /* Put error message here if not 0 */
7340);
7341
7342/*
7343** CAPI3REF: Enable Or Disable Extension Loading
7344** METHOD: sqlite3
7345**
7346** ^So as not to open security holes in older applications that are
7347** unprepared to deal with [extension loading], and as a means of disabling
7348** [extension loading] while evaluating user-entered SQL, the following API
7349** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
7350**
7351** ^Extension loading is off by default.
7352** ^Call the sqlite3_enable_load_extension() routine with onoff==1
7353** to turn extension loading on and call it with onoff==0 to turn
7354** it back off again.
7355**
7356** ^This interface enables or disables both the C-API
7357** [sqlite3_load_extension()] and the SQL function [load_extension()].
7358** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
7359** to enable or disable only the C-API.)^
7360**
7361** <b>Security warning:</b> It is recommended that extension loading
7362** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
7363** rather than this interface, so the [load_extension()] SQL function
7364** remains disabled. This will prevent SQL injections from giving attackers
7365** access to extension loading capabilities.
7366*/
7367SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
7368
7369/*
7370** CAPI3REF: Automatically Load Statically Linked Extensions
7371**
7372** ^This interface causes the xEntryPoint() function to be invoked for
7373** each new [database connection] that is created. The idea here is that
7374** xEntryPoint() is the entry point for a statically linked [SQLite extension]
7375** that is to be automatically loaded into all new database connections.
7376**
7377** ^(Even though the function prototype shows that xEntryPoint() takes
7378** no arguments and returns void, SQLite invokes xEntryPoint() with three
7379** arguments and expects an integer result as if the signature of the
7380** entry point where as follows:
7381**
7382** <blockquote><pre>
7383** &nbsp; int xEntryPoint(
7384** &nbsp; sqlite3 *db,
7385** &nbsp; const char **pzErrMsg,
7386** &nbsp; const struct sqlite3_api_routines *pThunk
7387** &nbsp; );
7388** </pre></blockquote>)^
7389**
7390** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
7391** point to an appropriate error message (obtained from [sqlite3_mprintf()])
7392** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
7393** is NULL before calling the xEntryPoint(). ^SQLite will invoke
7394** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
7395** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
7396** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
7397**
7398** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
7399** on the list of automatic extensions is a harmless no-op. ^No entry point
7400** will be called more than once for each database connection that is opened.
7401**
7402** See also: [sqlite3_reset_auto_extension()]
7403** and [sqlite3_cancel_auto_extension()]
7404*/
7405SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));
7406
7407/*
7408** CAPI3REF: Cancel Automatic Extension Loading
7409**
7410** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
7411** initialization routine X that was registered using a prior call to
7412** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)]
7413** routine returns 1 if initialization routine X was successfully
7414** unregistered and it returns 0 if X was not on the list of initialization
7415** routines.
7416*/
7417SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
7418
7419/*
7420** CAPI3REF: Reset Automatic Extension Loading
7421**
7422** ^This interface disables all automatic extensions previously
7423** registered using [sqlite3_auto_extension()].
7424*/
7425SQLITE_API void sqlite3_reset_auto_extension(void);
7426
7427/*
7428** Structures used by the virtual table interface
7429*/
7430typedef struct sqlite3_vtab sqlite3_vtab;
7431typedef struct sqlite3_index_info sqlite3_index_info;
7432typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
7433typedef struct sqlite3_module sqlite3_module;
7434
7435/*
7436** CAPI3REF: Virtual Table Object
7437** KEYWORDS: sqlite3_module {virtual table module}
7438**
7439** This structure, sometimes called a "virtual table module",
7440** defines the implementation of a [virtual table].
7441** This structure consists mostly of methods for the module.
7442**
7443** ^A virtual table module is created by filling in a persistent
7444** instance of this structure and passing a pointer to that instance
7445** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
7446** ^The registration remains valid until it is replaced by a different
7447** module or until the [database connection] closes. The content
7448** of this structure must not change while it is registered with
7449** any database connection.
7450*/
7451struct sqlite3_module {
7452 int iVersion;
7453 int (*xCreate)(sqlite3*, void *pAux,
7454 int argc, const char *const*argv,
7455 sqlite3_vtab **ppVTab, char**);
7456 int (*xConnect)(sqlite3*, void *pAux,
7457 int argc, const char *const*argv,
7458 sqlite3_vtab **ppVTab, char**);
7459 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
7460 int (*xDisconnect)(sqlite3_vtab *pVTab);
7461 int (*xDestroy)(sqlite3_vtab *pVTab);
7462 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
7463 int (*xClose)(sqlite3_vtab_cursor*);
7464 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
7465 int argc, sqlite3_value **argv);
7466 int (*xNext)(sqlite3_vtab_cursor*);
7467 int (*xEof)(sqlite3_vtab_cursor*);
7468 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
7469 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
7470 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
7471 int (*xBegin)(sqlite3_vtab *pVTab);
7472 int (*xSync)(sqlite3_vtab *pVTab);
7473 int (*xCommit)(sqlite3_vtab *pVTab);
7474 int (*xRollback)(sqlite3_vtab *pVTab);
7475 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
7476 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
7477 void **ppArg);
7478 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
7479 /* The methods above are in version 1 of the sqlite_module object. Those
7480 ** below are for version 2 and greater. */
7481 int (*xSavepoint)(sqlite3_vtab *pVTab, int);
7482 int (*xRelease)(sqlite3_vtab *pVTab, int);
7483 int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
7484 /* The methods above are in versions 1 and 2 of the sqlite_module object.
7485 ** Those below are for version 3 and greater. */
7486 int (*xShadowName)(const char*);
7487 /* The methods above are in versions 1 through 3 of the sqlite_module object.
7488 ** Those below are for version 4 and greater. */
7489 int (*xIntegrity)(sqlite3_vtab *pVTab, const char *zSchema,
7490 const char *zTabName, int mFlags, char **pzErr);
7491};
7492
7493/*
7494** CAPI3REF: Virtual Table Indexing Information
7495** KEYWORDS: sqlite3_index_info
7496**
7497** The sqlite3_index_info structure and its substructures is used as part
7498** of the [virtual table] interface to
7499** pass information into and receive the reply from the [xBestIndex]
7500** method of a [virtual table module]. The fields under **Inputs** are the
7501** inputs to xBestIndex and are read-only. xBestIndex inserts its
7502** results into the **Outputs** fields.
7503**
7504** ^(The aConstraint[] array records WHERE clause constraints of the form:
7505**
7506** <blockquote>column OP expr</blockquote>
7507**
7508** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^ ^(The particular operator is
7509** stored in aConstraint[].op using one of the
7510** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
7511** ^(The index of the column is stored in
7512** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
7513** expr on the right-hand side can be evaluated (and thus the constraint
7514** is usable) and false if it cannot.)^
7515**
7516** ^The optimizer automatically inverts terms of the form "expr OP column"
7517** and makes other simplifications to the WHERE clause in an attempt to
7518** get as many WHERE clause terms into the form shown above as possible.
7519** ^The aConstraint[] array only reports WHERE clause terms that are
7520** relevant to the particular virtual table being queried.
7521**
7522** ^Information about the ORDER BY clause is stored in aOrderBy[].
7523** ^Each term of aOrderBy records a column of the ORDER BY clause.
7524**
7525** The colUsed field indicates which columns of the virtual table may be
7526** required by the current scan. Virtual table columns are numbered from
7527** zero in the order in which they appear within the CREATE TABLE statement
7528** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
7529** the corresponding bit is set within the colUsed mask if the column may be
7530** required by SQLite. If the table has at least 64 columns and any column
7531** to the right of the first 63 is required, then bit 63 of colUsed is also
7532** set. In other words, column iCol may be required if the expression
7533** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
7534** non-zero.
7535**
7536** The [xBestIndex] method must fill aConstraintUsage[] with information
7537** about what parameters to pass to xFilter. ^If argvIndex>0 then
7538** the right-hand side of the corresponding aConstraint[] is evaluated
7539** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
7540** is true, then the constraint is assumed to be fully handled by the
7541** virtual table and might not be checked again by the byte code.)^ ^(The
7542** aConstraintUsage[].omit flag is an optimization hint. When the omit flag
7543** is left in its default setting of false, the constraint will always be
7544** checked separately in byte code. If the omit flag is change to true, then
7545** the constraint may or may not be checked in byte code. In other words,
7546** when the omit flag is true there is no guarantee that the constraint will
7547** not be checked again using byte code.)^
7548**
7549** ^The idxNum and idxStr values are recorded and passed into the
7550** [xFilter] method.
7551** ^[sqlite3_free()] is used to free idxStr if and only if
7552** needToFreeIdxStr is true.
7553**
7554** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
7555** the correct order to satisfy the ORDER BY clause so that no separate
7556** sorting step is required.
7557**
7558** ^The estimatedCost value is an estimate of the cost of a particular
7559** strategy. A cost of N indicates that the cost of the strategy is similar
7560** to a linear scan of an SQLite table with N rows. A cost of log(N)
7561** indicates that the expense of the operation is similar to that of a
7562** binary search on a unique indexed field of an SQLite table with N rows.
7563**
7564** ^The estimatedRows value is an estimate of the number of rows that
7565** will be returned by the strategy.
7566**
7567** The xBestIndex method may optionally populate the idxFlags field with a
7568** mask of SQLITE_INDEX_SCAN_* flags. One such flag is
7569** [SQLITE_INDEX_SCAN_HEX], which if set causes the [EXPLAIN QUERY PLAN]
7570** output to show the idxNum has hex instead of as decimal. Another flag is
7571** SQLITE_INDEX_SCAN_UNIQUE, which if set indicates that the query plan will
7572** return at most one row.
7573**
7574** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
7575** SQLite also assumes that if a call to the xUpdate() method is made as
7576** part of the same statement to delete or update a virtual table row and the
7577** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
7578** any database changes. In other words, if the xUpdate() returns
7579** SQLITE_CONSTRAINT, the database contents must be exactly as they were
7580** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
7581** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
7582** the xUpdate method are automatically rolled back by SQLite.
7583**
7584** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
7585** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
7586** If a virtual table extension is
7587** used with an SQLite version earlier than 3.8.2, the results of attempting
7588** to read or write the estimatedRows field are undefined (but are likely
7589** to include crashing the application). The estimatedRows field should
7590** therefore only be used if [sqlite3_libversion_number()] returns a
7591** value greater than or equal to 3008002. Similarly, the idxFlags field
7592** was added for [version 3.9.0] ([dateof:3.9.0]).
7593** It may therefore only be used if
7594** sqlite3_libversion_number() returns a value greater than or equal to
7595** 3009000.
7596*/
7597struct sqlite3_index_info {
7598 /* Inputs */
7599 int nConstraint; /* Number of entries in aConstraint */
7600 struct sqlite3_index_constraint {
7601 int iColumn; /* Column constrained. -1 for ROWID */
7602 unsigned char op; /* Constraint operator */
7603 unsigned char usable; /* True if this constraint is usable */
7604 int iTermOffset; /* Used internally - xBestIndex should ignore */
7605 } *aConstraint; /* Table of WHERE clause constraints */
7606 int nOrderBy; /* Number of terms in the ORDER BY clause */
7607 struct sqlite3_index_orderby {
7608 int iColumn; /* Column number */
7609 unsigned char desc; /* True for DESC. False for ASC. */
7610 } *aOrderBy; /* The ORDER BY clause */
7611 /* Outputs */
7612 struct sqlite3_index_constraint_usage {
7613 int argvIndex; /* if >0, constraint is part of argv to xFilter */
7614 unsigned char omit; /* Do not code a test for this constraint */
7615 } *aConstraintUsage;
7616 int idxNum; /* Number used to identify the index */
7617 char *idxStr; /* String, possibly obtained from sqlite3_malloc */
7618 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
7619 int orderByConsumed; /* True if output is already ordered */
7620 double estimatedCost; /* Estimated cost of using this index */
7621 /* Fields below are only available in SQLite 3.8.2 and later */
7622 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */
7623 /* Fields below are only available in SQLite 3.9.0 and later */
7624 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */
7625 /* Fields below are only available in SQLite 3.10.0 and later */
7626 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */
7627};
7628
7629/*
7630** CAPI3REF: Virtual Table Scan Flags
7631**
7632** Virtual table implementations are allowed to set the
7633** [sqlite3_index_info].idxFlags field to some combination of
7634** these bits.
7635*/
7636#define SQLITE_INDEX_SCAN_UNIQUE 0x00000001 /* Scan visits at most 1 row */
7637#define SQLITE_INDEX_SCAN_HEX 0x00000002 /* Display idxNum as hex */
7638 /* in EXPLAIN QUERY PLAN */
7639
7640/*
7641** CAPI3REF: Virtual Table Constraint Operator Codes
7642**
7643** These macros define the allowed values for the
7644** [sqlite3_index_info].aConstraint[].op field. Each value represents
7645** an operator that is part of a constraint term in the WHERE clause of
7646** a query that uses a [virtual table].
7647**
7648** ^The left-hand operand of the operator is given by the corresponding
7649** aConstraint[].iColumn field. ^An iColumn of -1 indicates the left-hand
7650** operand is the rowid.
7651** The SQLITE_INDEX_CONSTRAINT_LIMIT and SQLITE_INDEX_CONSTRAINT_OFFSET
7652** operators have no left-hand operand, and so for those operators the
7653** corresponding aConstraint[].iColumn is meaningless and should not be
7654** used.
7655**
7656** All operator values from SQLITE_INDEX_CONSTRAINT_FUNCTION through
7657** value 255 are reserved to represent functions that are overloaded
7658** by the [xFindFunction|xFindFunction method] of the virtual table
7659** implementation.
7660**
7661** The right-hand operands for each constraint might be accessible using
7662** the [sqlite3_vtab_rhs_value()] interface. Usually the right-hand
7663** operand is only available if it appears as a single constant literal
7664** in the input SQL. If the right-hand operand is another column or an
7665** expression (even a constant expression) or a parameter, then the
7666** sqlite3_vtab_rhs_value() probably will not be able to extract it.
7667** ^The SQLITE_INDEX_CONSTRAINT_ISNULL and
7668** SQLITE_INDEX_CONSTRAINT_ISNOTNULL operators have no right-hand operand
7669** and hence calls to sqlite3_vtab_rhs_value() for those operators will
7670** always return SQLITE_NOTFOUND.
7671**
7672** The collating sequence to be used for comparison can be found using
7673** the [sqlite3_vtab_collation()] interface. For most real-world virtual
7674** tables, the collating sequence of constraints does not matter (for example
7675** because the constraints are numeric) and so the sqlite3_vtab_collation()
7676** interface is not commonly needed.
7677*/
7678#define SQLITE_INDEX_CONSTRAINT_EQ 2
7679#define SQLITE_INDEX_CONSTRAINT_GT 4
7680#define SQLITE_INDEX_CONSTRAINT_LE 8
7681#define SQLITE_INDEX_CONSTRAINT_LT 16
7682#define SQLITE_INDEX_CONSTRAINT_GE 32
7683#define SQLITE_INDEX_CONSTRAINT_MATCH 64
7684#define SQLITE_INDEX_CONSTRAINT_LIKE 65
7685#define SQLITE_INDEX_CONSTRAINT_GLOB 66
7686#define SQLITE_INDEX_CONSTRAINT_REGEXP 67
7687#define SQLITE_INDEX_CONSTRAINT_NE 68
7688#define SQLITE_INDEX_CONSTRAINT_ISNOT 69
7689#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70
7690#define SQLITE_INDEX_CONSTRAINT_ISNULL 71
7691#define SQLITE_INDEX_CONSTRAINT_IS 72
7692#define SQLITE_INDEX_CONSTRAINT_LIMIT 73
7693#define SQLITE_INDEX_CONSTRAINT_OFFSET 74
7694#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150
7695
7696/*
7697** CAPI3REF: Register A Virtual Table Implementation
7698** METHOD: sqlite3
7699**
7700** ^These routines are used to register a new [virtual table module] name.
7701** ^Module names must be registered before
7702** creating a new [virtual table] using the module and before using a
7703** preexisting [virtual table] for the module.
7704**
7705** ^The module name is registered on the [database connection] specified
7706** by the first parameter. ^The name of the module is given by the
7707** second parameter. ^The third parameter is a pointer to
7708** the implementation of the [virtual table module]. ^The fourth
7709** parameter is an arbitrary client data pointer that is passed through
7710** into the [xCreate] and [xConnect] methods of the virtual table module
7711** when a new virtual table is be being created or reinitialized.
7712**
7713** ^The sqlite3_create_module_v2() interface has a fifth parameter which
7714** is a pointer to a destructor for the pClientData. ^SQLite will
7715** invoke the destructor function (if it is not NULL) when SQLite
7716** no longer needs the pClientData pointer. ^The destructor will also
7717** be invoked if the call to sqlite3_create_module_v2() fails.
7718** ^The sqlite3_create_module()
7719** interface is equivalent to sqlite3_create_module_v2() with a NULL
7720** destructor.
7721**
7722** ^If the third parameter (the pointer to the sqlite3_module object) is
7723** NULL then no new module is created and any existing modules with the
7724** same name are dropped.
7725**
7726** See also: [sqlite3_drop_modules()]
7727*/
7728SQLITE_API int sqlite3_create_module(
7729 sqlite3 *db, /* SQLite connection to register module with */
7730 const char *zName, /* Name of the module */
7731 const sqlite3_module *p, /* Methods for the module */
7732 void *pClientData /* Client data for xCreate/xConnect */
7733);
7734SQLITE_API int sqlite3_create_module_v2(
7735 sqlite3 *db, /* SQLite connection to register module with */
7736 const char *zName, /* Name of the module */
7737 const sqlite3_module *p, /* Methods for the module */
7738 void *pClientData, /* Client data for xCreate/xConnect */
7739 void(*xDestroy)(void*) /* Module destructor function */
7740);
7741
7742/*
7743** CAPI3REF: Remove Unnecessary Virtual Table Implementations
7744** METHOD: sqlite3
7745**
7746** ^The sqlite3_drop_modules(D,L) interface removes all virtual
7747** table modules from database connection D except those named on list L.
7748** The L parameter must be either NULL or a pointer to an array of pointers
7749** to strings where the array is terminated by a single NULL pointer.
7750** ^If the L parameter is NULL, then all virtual table modules are removed.
7751**
7752** See also: [sqlite3_create_module()]
7753*/
7754SQLITE_API int sqlite3_drop_modules(
7755 sqlite3 *db, /* Remove modules from this connection */
7756 const char **azKeep /* Except, do not remove the ones named here */
7757);
7758
7759/*
7760** CAPI3REF: Virtual Table Instance Object
7761** KEYWORDS: sqlite3_vtab
7762**
7763** Every [virtual table module] implementation uses a subclass
7764** of this object to describe a particular instance
7765** of the [virtual table]. Each subclass will
7766** be tailored to the specific needs of the module implementation.
7767** The purpose of this superclass is to define certain fields that are
7768** common to all module implementations.
7769**
7770** ^Virtual tables methods can set an error message by assigning a
7771** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
7772** take care that any prior string is freed by a call to [sqlite3_free()]
7773** prior to assigning a new string to zErrMsg. ^After the error message
7774** is delivered up to the client application, the string will be automatically
7775** freed by sqlite3_free() and the zErrMsg field will be zeroed.
7776*/
7777struct sqlite3_vtab {
7778 const sqlite3_module *pModule; /* The module for this virtual table */
7779 int nRef; /* Number of open cursors */
7780 char *zErrMsg; /* Error message from sqlite3_mprintf() */
7781 /* Virtual table implementations will typically add additional fields */
7782};
7783
7784/*
7785** CAPI3REF: Virtual Table Cursor Object
7786** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
7787**
7788** Every [virtual table module] implementation uses a subclass of the
7789** following structure to describe cursors that point into the
7790** [virtual table] and are used
7791** to loop through the virtual table. Cursors are created using the
7792** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
7793** by the [sqlite3_module.xClose | xClose] method. Cursors are used
7794** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
7795** of the module. Each module implementation will define
7796** the content of a cursor structure to suit its own needs.
7797**
7798** This superclass exists in order to define fields of the cursor that
7799** are common to all implementations.
7800*/
7801struct sqlite3_vtab_cursor {
7802 sqlite3_vtab *pVtab; /* Virtual table of this cursor */
7803 /* Virtual table implementations will typically add additional fields */
7804};
7805
7806/*
7807** CAPI3REF: Declare The Schema Of A Virtual Table
7808**
7809** ^The [xCreate] and [xConnect] methods of a
7810** [virtual table module] call this interface
7811** to declare the format (the names and datatypes of the columns) of
7812** the virtual tables they implement.
7813*/
7814SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
7815
7816/*
7817** CAPI3REF: Overload A Function For A Virtual Table
7818** METHOD: sqlite3
7819**
7820** ^(Virtual tables can provide alternative implementations of functions
7821** using the [xFindFunction] method of the [virtual table module].
7822** But global versions of those functions
7823** must exist in order to be overloaded.)^
7824**
7825** ^(This API makes sure a global version of a function with a particular
7826** name and number of parameters exists. If no such function exists
7827** before this API is called, a new function is created.)^ ^The implementation
7828** of the new function always causes an exception to be thrown. So
7829** the new function is not good for anything by itself. Its only
7830** purpose is to be a placeholder function that can be overloaded
7831** by a [virtual table].
7832*/
7833SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
7834
7835/*
7836** CAPI3REF: A Handle To An Open BLOB
7837** KEYWORDS: {BLOB handle} {BLOB handles}
7838**
7839** An instance of this object represents an open BLOB on which
7840** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
7841** ^Objects of this type are created by [sqlite3_blob_open()]
7842** and destroyed by [sqlite3_blob_close()].
7843** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
7844** can be used to read or write small subsections of the BLOB.
7845** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
7846*/
7847typedef struct sqlite3_blob sqlite3_blob;
7848
7849/*
7850** CAPI3REF: Open A BLOB For Incremental I/O
7851** METHOD: sqlite3
7852** CONSTRUCTOR: sqlite3_blob
7853**
7854** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
7855** in row iRow, column zColumn, table zTable in database zDb;
7856** in other words, the same BLOB that would be selected by:
7857**
7858** <pre>
7859** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
7860** </pre>)^
7861**
7862** ^(Parameter zDb is not the filename that contains the database, but
7863** rather the symbolic name of the database. For attached databases, this is
7864** the name that appears after the AS keyword in the [ATTACH] statement.
7865** For the main database file, the database name is "main". For TEMP
7866** tables, the database name is "temp".)^
7867**
7868** ^If the flags parameter is non-zero, then the BLOB is opened for read
7869** and write access. ^If the flags parameter is zero, the BLOB is opened for
7870** read-only access.
7871**
7872** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
7873** in *ppBlob. Otherwise an [error code] is returned and, unless the error
7874** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
7875** the API is not misused, it is always safe to call [sqlite3_blob_close()]
7876** on *ppBlob after this function it returns.
7877**
7878** This function fails with SQLITE_ERROR if any of the following are true:
7879** <ul>
7880** <li> ^(Database zDb does not exist)^,
7881** <li> ^(Table zTable does not exist within database zDb)^,
7882** <li> ^(Table zTable is a WITHOUT ROWID table)^,
7883** <li> ^(Column zColumn does not exist)^,
7884** <li> ^(Row iRow is not present in the table)^,
7885** <li> ^(The specified column of row iRow contains a value that is not
7886** a TEXT or BLOB value)^,
7887** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
7888** constraint and the blob is being opened for read/write access)^,
7889** <li> ^([foreign key constraints | Foreign key constraints] are enabled,
7890** column zColumn is part of a [child key] definition and the blob is
7891** being opened for read/write access)^.
7892** </ul>
7893**
7894** ^Unless it returns SQLITE_MISUSE, this function sets the
7895** [database connection] error code and message accessible via
7896** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
7897**
7898** A BLOB referenced by sqlite3_blob_open() may be read using the
7899** [sqlite3_blob_read()] interface and modified by using
7900** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a
7901** different row of the same table using the [sqlite3_blob_reopen()]
7902** interface. However, the column, table, or database of a [BLOB handle]
7903** cannot be changed after the [BLOB handle] is opened.
7904**
7905** ^(If the row that a BLOB handle points to is modified by an
7906** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
7907** then the BLOB handle is marked as "expired".
7908** This is true if any column of the row is changed, even a column
7909** other than the one the BLOB handle is open on.)^
7910** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
7911** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
7912** ^(Changes written into a BLOB prior to the BLOB expiring are not
7913** rolled back by the expiration of the BLOB. Such changes will eventually
7914** commit if the transaction continues to completion.)^
7915**
7916** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
7917** the opened blob. ^The size of a blob may not be changed by this
7918** interface. Use the [UPDATE] SQL command to change the size of a
7919** blob.
7920**
7921** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
7922** and the built-in [zeroblob] SQL function may be used to create a
7923** zero-filled blob to read or write using the incremental-blob interface.
7924**
7925** To avoid a resource leak, every open [BLOB handle] should eventually
7926** be released by a call to [sqlite3_blob_close()].
7927**
7928** See also: [sqlite3_blob_close()],
7929** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
7930** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
7931*/
7932SQLITE_API int sqlite3_blob_open(
7933 sqlite3*,
7934 const char *zDb,
7935 const char *zTable,
7936 const char *zColumn,
7937 sqlite3_int64 iRow,
7938 int flags,
7939 sqlite3_blob **ppBlob
7940);
7941
7942/*
7943** CAPI3REF: Move a BLOB Handle to a New Row
7944** METHOD: sqlite3_blob
7945**
7946** ^This function is used to move an existing [BLOB handle] so that it points
7947** to a different row of the same database table. ^The new row is identified
7948** by the rowid value passed as the second argument. Only the row can be
7949** changed. ^The database, table and column on which the blob handle is open
7950** remain the same. Moving an existing [BLOB handle] to a new row is
7951** faster than closing the existing handle and opening a new one.
7952**
7953** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
7954** it must exist and there must be either a blob or text value stored in
7955** the nominated column.)^ ^If the new row is not present in the table, or if
7956** it does not contain a blob or text value, or if another error occurs, an
7957** SQLite error code is returned and the blob handle is considered aborted.
7958** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
7959** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
7960** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
7961** always returns zero.
7962**
7963** ^This function sets the database handle error code and message.
7964*/
7965SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
7966
7967/*
7968** CAPI3REF: Close A BLOB Handle
7969** DESTRUCTOR: sqlite3_blob
7970**
7971** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
7972** unconditionally. Even if this routine returns an error code, the
7973** handle is still closed.)^
7974**
7975** ^If the blob handle being closed was opened for read-write access, and if
7976** the database is in auto-commit mode and there are no other open read-write
7977** blob handles or active write statements, the current transaction is
7978** committed. ^If an error occurs while committing the transaction, an error
7979** code is returned and the transaction rolled back.
7980**
7981** Calling this function with an argument that is not a NULL pointer or an
7982** open blob handle results in undefined behavior. ^Calling this routine
7983** with a null pointer (such as would be returned by a failed call to
7984** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
7985** is passed a valid open blob handle, the values returned by the
7986** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
7987*/
7988SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
7989
7990/*
7991** CAPI3REF: Return The Size Of An Open BLOB
7992** METHOD: sqlite3_blob
7993**
7994** ^Returns the size in bytes of the BLOB accessible via the
7995** successfully opened [BLOB handle] in its only argument. ^The
7996** incremental blob I/O routines can only read or overwriting existing
7997** blob content; they cannot change the size of a blob.
7998**
7999** This routine only works on a [BLOB handle] which has been created
8000** by a prior successful call to [sqlite3_blob_open()] and which has not
8001** been closed by [sqlite3_blob_close()]. Passing any other pointer in
8002** to this routine results in undefined and probably undesirable behavior.
8003*/
8004SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
8005
8006/*
8007** CAPI3REF: Read Data From A BLOB Incrementally
8008** METHOD: sqlite3_blob
8009**
8010** ^(This function is used to read data from an open [BLOB handle] into a
8011** caller-supplied buffer. N bytes of data are copied into buffer Z
8012** from the open BLOB, starting at offset iOffset.)^
8013**
8014** ^If offset iOffset is less than N bytes from the end of the BLOB,
8015** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
8016** less than zero, [SQLITE_ERROR] is returned and no data is read.
8017** ^The size of the blob (and hence the maximum value of N+iOffset)
8018** can be determined using the [sqlite3_blob_bytes()] interface.
8019**
8020** ^An attempt to read from an expired [BLOB handle] fails with an
8021** error code of [SQLITE_ABORT].
8022**
8023** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
8024** Otherwise, an [error code] or an [extended error code] is returned.)^
8025**
8026** This routine only works on a [BLOB handle] which has been created
8027** by a prior successful call to [sqlite3_blob_open()] and which has not
8028** been closed by [sqlite3_blob_close()]. Passing any other pointer in
8029** to this routine results in undefined and probably undesirable behavior.
8030**
8031** See also: [sqlite3_blob_write()].
8032*/
8033SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
8034
8035/*
8036** CAPI3REF: Write Data Into A BLOB Incrementally
8037** METHOD: sqlite3_blob
8038**
8039** ^(This function is used to write data into an open [BLOB handle] from a
8040** caller-supplied buffer. N bytes of data are copied from the buffer Z
8041** into the open BLOB, starting at offset iOffset.)^
8042**
8043** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
8044** Otherwise, an [error code] or an [extended error code] is returned.)^
8045** ^Unless SQLITE_MISUSE is returned, this function sets the
8046** [database connection] error code and message accessible via
8047** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
8048**
8049** ^If the [BLOB handle] passed as the first argument was not opened for
8050** writing (the flags parameter to [sqlite3_blob_open()] was zero),
8051** this function returns [SQLITE_READONLY].
8052**
8053** This function may only modify the contents of the BLOB; it is
8054** not possible to increase the size of a BLOB using this API.
8055** ^If offset iOffset is less than N bytes from the end of the BLOB,
8056** [SQLITE_ERROR] is returned and no data is written. The size of the
8057** BLOB (and hence the maximum value of N+iOffset) can be determined
8058** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
8059** than zero [SQLITE_ERROR] is returned and no data is written.
8060**
8061** ^An attempt to write to an expired [BLOB handle] fails with an
8062** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
8063** before the [BLOB handle] expired are not rolled back by the
8064** expiration of the handle, though of course those changes might
8065** have been overwritten by the statement that expired the BLOB handle
8066** or by other independent statements.
8067**
8068** This routine only works on a [BLOB handle] which has been created
8069** by a prior successful call to [sqlite3_blob_open()] and which has not
8070** been closed by [sqlite3_blob_close()]. Passing any other pointer in
8071** to this routine results in undefined and probably undesirable behavior.
8072**
8073** See also: [sqlite3_blob_read()].
8074*/
8075SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
8076
8077/*
8078** CAPI3REF: Virtual File System Objects
8079**
8080** A virtual filesystem (VFS) is an [sqlite3_vfs] object
8081** that SQLite uses to interact
8082** with the underlying operating system. Most SQLite builds come with a
8083** single default VFS that is appropriate for the host computer.
8084** New VFSes can be registered and existing VFSes can be unregistered.
8085** The following interfaces are provided.
8086**
8087** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
8088** ^Names are case sensitive.
8089** ^Names are zero-terminated UTF-8 strings.
8090** ^If there is no match, a NULL pointer is returned.
8091** ^If zVfsName is NULL then the default VFS is returned.
8092**
8093** ^New VFSes are registered with sqlite3_vfs_register().
8094** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
8095** ^The same VFS can be registered multiple times without injury.
8096** ^To make an existing VFS into the default VFS, register it again
8097** with the makeDflt flag set. If two different VFSes with the
8098** same name are registered, the behavior is undefined. If a
8099** VFS is registered with a name that is NULL or an empty string,
8100** then the behavior is undefined.
8101**
8102** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
8103** ^(If the default VFS is unregistered, another VFS is chosen as
8104** the default. The choice for the new VFS is arbitrary.)^
8105*/
8106SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
8107SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
8108SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
8109
8110/*
8111** CAPI3REF: Mutexes
8112**
8113** The SQLite core uses these routines for thread
8114** synchronization. Though they are intended for internal
8115** use by SQLite, code that links against SQLite is
8116** permitted to use any of these routines.
8117**
8118** The SQLite source code contains multiple implementations
8119** of these mutex routines. An appropriate implementation
8120** is selected automatically at compile-time. The following
8121** implementations are available in the SQLite core:
8122**
8123** <ul>
8124** <li> SQLITE_MUTEX_PTHREADS
8125** <li> SQLITE_MUTEX_W32
8126** <li> SQLITE_MUTEX_NOOP
8127** </ul>
8128**
8129** The SQLITE_MUTEX_NOOP implementation is a set of routines
8130** that does no real locking and is appropriate for use in
8131** a single-threaded application. The SQLITE_MUTEX_PTHREADS and
8132** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
8133** and Windows.
8134**
8135** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
8136** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
8137** implementation is included with the library. In this case the
8138** application must supply a custom mutex implementation using the
8139** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
8140** before calling sqlite3_initialize() or any other public sqlite3_
8141** function that calls sqlite3_initialize().
8142**
8143** ^The sqlite3_mutex_alloc() routine allocates a new
8144** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
8145** routine returns NULL if it is unable to allocate the requested
8146** mutex. The argument to sqlite3_mutex_alloc() must one of these
8147** integer constants:
8148**
8149** <ul>
8150** <li> SQLITE_MUTEX_FAST
8151** <li> SQLITE_MUTEX_RECURSIVE
8152** <li> SQLITE_MUTEX_STATIC_MAIN
8153** <li> SQLITE_MUTEX_STATIC_MEM
8154** <li> SQLITE_MUTEX_STATIC_OPEN
8155** <li> SQLITE_MUTEX_STATIC_PRNG
8156** <li> SQLITE_MUTEX_STATIC_LRU
8157** <li> SQLITE_MUTEX_STATIC_PMEM
8158** <li> SQLITE_MUTEX_STATIC_APP1
8159** <li> SQLITE_MUTEX_STATIC_APP2
8160** <li> SQLITE_MUTEX_STATIC_APP3
8161** <li> SQLITE_MUTEX_STATIC_VFS1
8162** <li> SQLITE_MUTEX_STATIC_VFS2
8163** <li> SQLITE_MUTEX_STATIC_VFS3
8164** </ul>
8165**
8166** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
8167** cause sqlite3_mutex_alloc() to create
8168** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
8169** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
8170** The mutex implementation does not need to make a distinction
8171** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
8172** not want to. SQLite will only request a recursive mutex in
8173** cases where it really needs one. If a faster non-recursive mutex
8174** implementation is available on the host platform, the mutex subsystem
8175** might return such a mutex in response to SQLITE_MUTEX_FAST.
8176**
8177** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
8178** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
8179** a pointer to a static preexisting mutex. ^Nine static mutexes are
8180** used by the current version of SQLite. Future versions of SQLite
8181** may add additional static mutexes. Static mutexes are for internal
8182** use by SQLite only. Applications that use SQLite mutexes should
8183** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
8184** SQLITE_MUTEX_RECURSIVE.
8185**
8186** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
8187** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
8188** returns a different mutex on every call. ^For the static
8189** mutex types, the same mutex is returned on every call that has
8190** the same type number.
8191**
8192** ^The sqlite3_mutex_free() routine deallocates a previously
8193** allocated dynamic mutex. Attempting to deallocate a static
8194** mutex results in undefined behavior.
8195**
8196** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
8197** to enter a mutex. ^If another thread is already within the mutex,
8198** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
8199** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
8200** upon successful entry. ^(Mutexes created using
8201** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
8202** In such cases, the
8203** mutex must be exited an equal number of times before another thread
8204** can enter.)^ If the same thread tries to enter any mutex other
8205** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
8206**
8207** ^(Some systems (for example, Windows 95) do not support the operation
8208** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
8209** will always return SQLITE_BUSY. In most cases the SQLite core only uses
8210** sqlite3_mutex_try() as an optimization, so this is acceptable
8211** behavior. The exceptions are unix builds that set the
8212** SQLITE_ENABLE_SETLK_TIMEOUT build option. In that case a working
8213** sqlite3_mutex_try() is required.)^
8214**
8215** ^The sqlite3_mutex_leave() routine exits a mutex that was
8216** previously entered by the same thread. The behavior
8217** is undefined if the mutex is not currently entered by the
8218** calling thread or is not currently allocated.
8219**
8220** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(),
8221** sqlite3_mutex_leave(), or sqlite3_mutex_free() is a NULL pointer,
8222** then any of the four routines behaves as a no-op.
8223**
8224** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
8225*/
8226SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
8227SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
8228SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
8229SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
8230SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
8231
8232/*
8233** CAPI3REF: Mutex Methods Object
8234**
8235** An instance of this structure defines the low-level routines
8236** used to allocate and use mutexes.
8237**
8238** Usually, the default mutex implementations provided by SQLite are
8239** sufficient, however the application has the option of substituting a custom
8240** implementation for specialized deployments or systems for which SQLite
8241** does not provide a suitable implementation. In this case, the application
8242** creates and populates an instance of this structure to pass
8243** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
8244** Additionally, an instance of this structure can be used as an
8245** output variable when querying the system for the current mutex
8246** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
8247**
8248** ^The xMutexInit method defined by this structure is invoked as
8249** part of system initialization by the sqlite3_initialize() function.
8250** ^The xMutexInit routine is called by SQLite exactly once for each
8251** effective call to [sqlite3_initialize()].
8252**
8253** ^The xMutexEnd method defined by this structure is invoked as
8254** part of system shutdown by the sqlite3_shutdown() function. The
8255** implementation of this method is expected to release all outstanding
8256** resources obtained by the mutex methods implementation, especially
8257** those obtained by the xMutexInit method. ^The xMutexEnd()
8258** interface is invoked exactly once for each call to [sqlite3_shutdown()].
8259**
8260** ^(The remaining seven methods defined by this structure (xMutexAlloc,
8261** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
8262** xMutexNotheld) implement the following interfaces (respectively):
8263**
8264** <ul>
8265** <li> [sqlite3_mutex_alloc()] </li>
8266** <li> [sqlite3_mutex_free()] </li>
8267** <li> [sqlite3_mutex_enter()] </li>
8268** <li> [sqlite3_mutex_try()] </li>
8269** <li> [sqlite3_mutex_leave()] </li>
8270** <li> [sqlite3_mutex_held()] </li>
8271** <li> [sqlite3_mutex_notheld()] </li>
8272** </ul>)^
8273**
8274** The only difference is that the public sqlite3_XXX functions enumerated
8275** above silently ignore any invocations that pass a NULL pointer instead
8276** of a valid mutex handle. The implementations of the methods defined
8277** by this structure are not required to handle this case. The results
8278** of passing a NULL pointer instead of a valid mutex handle are undefined
8279** (i.e. it is acceptable to provide an implementation that segfaults if
8280** it is passed a NULL pointer).
8281**
8282** The xMutexInit() method must be threadsafe. It must be harmless to
8283** invoke xMutexInit() multiple times within the same process and without
8284** intervening calls to xMutexEnd(). Second and subsequent calls to
8285** xMutexInit() must be no-ops.
8286**
8287** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
8288** and its associates). Similarly, xMutexAlloc() must not use SQLite memory
8289** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
8290** memory allocation for a fast or recursive mutex.
8291**
8292** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
8293** called, but only if the prior call to xMutexInit returned SQLITE_OK.
8294** If xMutexInit fails in any way, it is expected to clean up after itself
8295** prior to returning.
8296*/
8297typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
8298struct sqlite3_mutex_methods {
8299 int (*xMutexInit)(void);
8300 int (*xMutexEnd)(void);
8301 sqlite3_mutex *(*xMutexAlloc)(int);
8302 void (*xMutexFree)(sqlite3_mutex *);
8303 void (*xMutexEnter)(sqlite3_mutex *);
8304 int (*xMutexTry)(sqlite3_mutex *);
8305 void (*xMutexLeave)(sqlite3_mutex *);
8306 int (*xMutexHeld)(sqlite3_mutex *);
8307 int (*xMutexNotheld)(sqlite3_mutex *);
8308};
8309
8310/*
8311** CAPI3REF: Mutex Verification Routines
8312**
8313** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
8314** are intended for use inside assert() statements. The SQLite core
8315** never uses these routines except inside an assert() and applications
8316** are advised to follow the lead of the core. The SQLite core only
8317** provides implementations for these routines when it is compiled
8318** with the SQLITE_DEBUG flag. External mutex implementations
8319** are only required to provide these routines if SQLITE_DEBUG is
8320** defined and if NDEBUG is not defined.
8321**
8322** These routines should return true if the mutex in their argument
8323** is held or not held, respectively, by the calling thread.
8324**
8325** The implementation is not required to provide versions of these
8326** routines that actually work. If the implementation does not provide working
8327** versions of these routines, it should at least provide stubs that always
8328** return true so that one does not get spurious assertion failures.
8329**
8330** If the argument to sqlite3_mutex_held() is a NULL pointer then
8331** the routine should return 1. This seems counter-intuitive since
8332** clearly the mutex cannot be held if it does not exist. But
8333** the reason the mutex does not exist is because the build is not
8334** using mutexes. And we do not want the assert() containing the
8335** call to sqlite3_mutex_held() to fail, so a non-zero return is
8336** the appropriate thing to do. The sqlite3_mutex_notheld()
8337** interface should also return 1 when given a NULL pointer.
8338*/
8339#ifndef NDEBUG
8340SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
8341SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
8342#endif
8343
8344/*
8345** CAPI3REF: Mutex Types
8346**
8347** The [sqlite3_mutex_alloc()] interface takes a single argument
8348** which is one of these integer constants.
8349**
8350** The set of static mutexes may change from one SQLite release to the
8351** next. Applications that override the built-in mutex logic must be
8352** prepared to accommodate additional static mutexes.
8353*/
8354#define SQLITE_MUTEX_FAST 0
8355#define SQLITE_MUTEX_RECURSIVE 1
8356#define SQLITE_MUTEX_STATIC_MAIN 2
8357#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
8358#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
8359#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
8360#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */
8361#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
8362#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
8363#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
8364#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */
8365#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */
8366#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */
8367#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */
8368#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */
8369#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */
8370
8371/* Legacy compatibility: */
8372#define SQLITE_MUTEX_STATIC_MASTER 2
8373
8374
8375/*
8376** CAPI3REF: Retrieve the mutex for a database connection
8377** METHOD: sqlite3
8378**
8379** ^This interface returns a pointer the [sqlite3_mutex] object that
8380** serializes access to the [database connection] given in the argument
8381** when the [threading mode] is Serialized.
8382** ^If the [threading mode] is Single-thread or Multi-thread then this
8383** routine returns a NULL pointer.
8384*/
8385SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
8386
8387/*
8388** CAPI3REF: Low-Level Control Of Database Files
8389** METHOD: sqlite3
8390** KEYWORDS: {file control}
8391**
8392** ^The [sqlite3_file_control()] interface makes a direct call to the
8393** xFileControl method for the [sqlite3_io_methods] object associated
8394** with a particular database identified by the second argument. ^The
8395** name of the database is "main" for the main database or "temp" for the
8396** TEMP database, or the name that appears after the AS keyword for
8397** databases that are added using the [ATTACH] SQL command.
8398** ^A NULL pointer can be used in place of "main" to refer to the
8399** main database file.
8400** ^The third and fourth parameters to this routine
8401** are passed directly through to the second and third parameters of
8402** the xFileControl method. ^The return value of the xFileControl
8403** method becomes the return value of this routine.
8404**
8405** A few opcodes for [sqlite3_file_control()] are handled directly
8406** by the SQLite core and never invoke the
8407** sqlite3_io_methods.xFileControl method.
8408** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
8409** a pointer to the underlying [sqlite3_file] object to be written into
8410** the space pointed to by the 4th parameter. The
8411** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns
8412** the [sqlite3_file] object associated with the journal file instead of
8413** the main database. The [SQLITE_FCNTL_VFS_POINTER] opcode returns
8414** a pointer to the underlying [sqlite3_vfs] object for the file.
8415** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter
8416** from the pager.
8417**
8418** ^If the second parameter (zDbName) does not match the name of any
8419** open database file, then SQLITE_ERROR is returned. ^This error
8420** code is not remembered and will not be recalled by [sqlite3_errcode()]
8421** or [sqlite3_errmsg()]. The underlying xFileControl method might
8422** also return SQLITE_ERROR. There is no way to distinguish between
8423** an incorrect zDbName and an SQLITE_ERROR return from the underlying
8424** xFileControl method.
8425**
8426** See also: [file control opcodes]
8427*/
8428SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
8429
8430/*
8431** CAPI3REF: Testing Interface
8432**
8433** ^The sqlite3_test_control() interface is used to read out internal
8434** state of SQLite and to inject faults into SQLite for testing
8435** purposes. ^The first parameter is an operation code that determines
8436** the number, meaning, and operation of all subsequent parameters.
8437**
8438** This interface is not for use by applications. It exists solely
8439** for verifying the correct operation of the SQLite library. Depending
8440** on how the SQLite library is compiled, this interface might not exist.
8441**
8442** The details of the operation codes, their meanings, the parameters
8443** they take, and what they do are all subject to change without notice.
8444** Unlike most of the SQLite API, this function is not guaranteed to
8445** operate consistently from one release to the next.
8446*/
8447SQLITE_API int sqlite3_test_control(int op, ...);
8448
8449/*
8450** CAPI3REF: Testing Interface Operation Codes
8451**
8452** These constants are the valid operation code parameters used
8453** as the first argument to [sqlite3_test_control()].
8454**
8455** These parameters and their meanings are subject to change
8456** without notice. These values are for testing purposes only.
8457** Applications should not use any of these parameters or the
8458** [sqlite3_test_control()] interface.
8459*/
8460#define SQLITE_TESTCTRL_FIRST 5
8461#define SQLITE_TESTCTRL_PRNG_SAVE 5
8462#define SQLITE_TESTCTRL_PRNG_RESTORE 6
8463#define SQLITE_TESTCTRL_PRNG_RESET 7 /* NOT USED */
8464#define SQLITE_TESTCTRL_FK_NO_ACTION 7
8465#define SQLITE_TESTCTRL_BITVEC_TEST 8
8466#define SQLITE_TESTCTRL_FAULT_INSTALL 9
8467#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
8468#define SQLITE_TESTCTRL_PENDING_BYTE 11
8469#define SQLITE_TESTCTRL_ASSERT 12
8470#define SQLITE_TESTCTRL_ALWAYS 13
8471#define SQLITE_TESTCTRL_RESERVE 14 /* NOT USED */
8472#define SQLITE_TESTCTRL_JSON_SELFCHECK 14
8473#define SQLITE_TESTCTRL_OPTIMIZATIONS 15
8474#define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */
8475#define SQLITE_TESTCTRL_GETOPT 16
8476#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */
8477#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS 17
8478#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
8479#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */
8480#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19
8481#define SQLITE_TESTCTRL_NEVER_CORRUPT 20
8482#define SQLITE_TESTCTRL_VDBE_COVERAGE 21
8483#define SQLITE_TESTCTRL_BYTEORDER 22
8484#define SQLITE_TESTCTRL_ISINIT 23
8485#define SQLITE_TESTCTRL_SORTER_MMAP 24
8486#define SQLITE_TESTCTRL_IMPOSTER 25
8487#define SQLITE_TESTCTRL_PARSER_COVERAGE 26
8488#define SQLITE_TESTCTRL_RESULT_INTREAL 27
8489#define SQLITE_TESTCTRL_PRNG_SEED 28
8490#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS 29
8491#define SQLITE_TESTCTRL_SEEK_COUNT 30
8492#define SQLITE_TESTCTRL_TRACEFLAGS 31
8493#define SQLITE_TESTCTRL_TUNE 32
8494#define SQLITE_TESTCTRL_LOGEST 33
8495#define SQLITE_TESTCTRL_USELONGDOUBLE 34 /* NOT USED */
8496#define SQLITE_TESTCTRL_LAST 34 /* Largest TESTCTRL */
8497
8498/*
8499** CAPI3REF: SQL Keyword Checking
8500**
8501** These routines provide access to the set of SQL language keywords
8502** recognized by SQLite. Applications can uses these routines to determine
8503** whether or not a specific identifier needs to be escaped (for example,
8504** by enclosing in double-quotes) so as not to confuse the parser.
8505**
8506** The sqlite3_keyword_count() interface returns the number of distinct
8507** keywords understood by SQLite.
8508**
8509** The sqlite3_keyword_name(N,Z,L) interface finds the 0-based N-th keyword and
8510** makes *Z point to that keyword expressed as UTF8 and writes the number
8511** of bytes in the keyword into *L. The string that *Z points to is not
8512** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns
8513** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
8514** or L are NULL or invalid pointers then calls to
8515** sqlite3_keyword_name(N,Z,L) result in undefined behavior.
8516**
8517** The sqlite3_keyword_check(Z,L) interface checks to see whether or not
8518** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
8519** if it is and zero if not.
8520**
8521** The parser used by SQLite is forgiving. It is often possible to use
8522** a keyword as an identifier as long as such use does not result in a
8523** parsing ambiguity. For example, the statement
8524** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
8525** creates a new table named "BEGIN" with three columns named
8526** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid
8527** using keywords as identifiers. Common techniques used to avoid keyword
8528** name collisions include:
8529** <ul>
8530** <li> Put all identifier names inside double-quotes. This is the official
8531** SQL way to escape identifier names.
8532** <li> Put identifier names inside &#91;...&#93;. This is not standard SQL,
8533** but it is what SQL Server does and so lots of programmers use this
8534** technique.
8535** <li> Begin every identifier with the letter "Z" as no SQL keywords start
8536** with "Z".
8537** <li> Include a digit somewhere in every identifier name.
8538** </ul>
8539**
8540** Note that the number of keywords understood by SQLite can depend on
8541** compile-time options. For example, "VACUUM" is not a keyword if
8542** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option. Also,
8543** new keywords may be added to future releases of SQLite.
8544*/
8545SQLITE_API int sqlite3_keyword_count(void);
8546SQLITE_API int sqlite3_keyword_name(int,const char**,int*);
8547SQLITE_API int sqlite3_keyword_check(const char*,int);
8548
8549/*
8550** CAPI3REF: Dynamic String Object
8551** KEYWORDS: {dynamic string}
8552**
8553** An instance of the sqlite3_str object contains a dynamically-sized
8554** string under construction.
8555**
8556** The lifecycle of an sqlite3_str object is as follows:
8557** <ol>
8558** <li> ^The sqlite3_str object is created using [sqlite3_str_new()].
8559** <li> ^Text is appended to the sqlite3_str object using various
8560** methods, such as [sqlite3_str_appendf()].
8561** <li> ^The sqlite3_str object is destroyed and the string it created
8562** is returned using the [sqlite3_str_finish()] interface.
8563** </ol>
8564*/
8565typedef struct sqlite3_str sqlite3_str;
8566
8567/*
8568** CAPI3REF: Create A New Dynamic String Object
8569** CONSTRUCTOR: sqlite3_str
8570**
8571** ^The [sqlite3_str_new(D)] interface allocates and initializes
8572** a new [sqlite3_str] object. To avoid memory leaks, the object returned by
8573** [sqlite3_str_new()] must be freed by a subsequent call to
8574** [sqlite3_str_finish(X)].
8575**
8576** ^The [sqlite3_str_new(D)] interface always returns a pointer to a
8577** valid [sqlite3_str] object, though in the event of an out-of-memory
8578** error the returned object might be a special singleton that will
8579** silently reject new text, always return SQLITE_NOMEM from
8580** [sqlite3_str_errcode()], always return 0 for
8581** [sqlite3_str_length()], and always return NULL from
8582** [sqlite3_str_finish(X)]. It is always safe to use the value
8583** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter
8584** to any of the other [sqlite3_str] methods.
8585**
8586** The D parameter to [sqlite3_str_new(D)] may be NULL. If the
8587** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum
8588** length of the string contained in the [sqlite3_str] object will be
8589** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead
8590** of [SQLITE_MAX_LENGTH].
8591*/
8592SQLITE_API sqlite3_str *sqlite3_str_new(sqlite3*);
8593
8594/*
8595** CAPI3REF: Finalize A Dynamic String
8596** DESTRUCTOR: sqlite3_str
8597**
8598** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X
8599** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()]
8600** that contains the constructed string. The calling application should
8601** pass the returned value to [sqlite3_free()] to avoid a memory leak.
8602** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any
8603** errors were encountered during construction of the string. ^The
8604** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the
8605** string in [sqlite3_str] object X is zero bytes long.
8606*/
8607SQLITE_API char *sqlite3_str_finish(sqlite3_str*);
8608
8609/*
8610** CAPI3REF: Add Content To A Dynamic String
8611** METHOD: sqlite3_str
8612**
8613** These interfaces add content to an sqlite3_str object previously obtained
8614** from [sqlite3_str_new()].
8615**
8616** ^The [sqlite3_str_appendf(X,F,...)] and
8617** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf]
8618** functionality of SQLite to append formatted text onto the end of
8619** [sqlite3_str] object X.
8620**
8621** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S
8622** onto the end of the [sqlite3_str] object X. N must be non-negative.
8623** S must contain at least N non-zero bytes of content. To append a
8624** zero-terminated string in its entirety, use the [sqlite3_str_appendall()]
8625** method instead.
8626**
8627** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of
8628** zero-terminated string S onto the end of [sqlite3_str] object X.
8629**
8630** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the
8631** single-byte character C onto the end of [sqlite3_str] object X.
8632** ^This method can be used, for example, to add whitespace indentation.
8633**
8634** ^The [sqlite3_str_reset(X)] method resets the string under construction
8635** inside [sqlite3_str] object X back to zero bytes in length.
8636**
8637** These methods do not return a result code. ^If an error occurs, that fact
8638** is recorded in the [sqlite3_str] object and can be recovered by a
8639** subsequent call to [sqlite3_str_errcode(X)].
8640*/
8641SQLITE_API void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...);
8642SQLITE_API void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list);
8643SQLITE_API void sqlite3_str_append(sqlite3_str*, const char *zIn, int N);
8644SQLITE_API void sqlite3_str_appendall(sqlite3_str*, const char *zIn);
8645SQLITE_API void sqlite3_str_appendchar(sqlite3_str*, int N, char C);
8646SQLITE_API void sqlite3_str_reset(sqlite3_str*);
8647
8648/*
8649** CAPI3REF: Status Of A Dynamic String
8650** METHOD: sqlite3_str
8651**
8652** These interfaces return the current status of an [sqlite3_str] object.
8653**
8654** ^If any prior errors have occurred while constructing the dynamic string
8655** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return
8656** an appropriate error code. ^The [sqlite3_str_errcode(X)] method returns
8657** [SQLITE_NOMEM] following any out-of-memory error, or
8658** [SQLITE_TOOBIG] if the size of the dynamic string exceeds
8659** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors.
8660**
8661** ^The [sqlite3_str_length(X)] method returns the current length, in bytes,
8662** of the dynamic string under construction in [sqlite3_str] object X.
8663** ^The length returned by [sqlite3_str_length(X)] does not include the
8664** zero-termination byte.
8665**
8666** ^The [sqlite3_str_value(X)] method returns a pointer to the current
8667** content of the dynamic string under construction in X. The value
8668** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X
8669** and might be freed or altered by any subsequent method on the same
8670** [sqlite3_str] object. Applications must not used the pointer returned
8671** [sqlite3_str_value(X)] after any subsequent method call on the same
8672** object. ^Applications may change the content of the string returned
8673** by [sqlite3_str_value(X)] as long as they do not write into any bytes
8674** outside the range of 0 to [sqlite3_str_length(X)] and do not read or
8675** write any byte after any subsequent sqlite3_str method call.
8676*/
8677SQLITE_API int sqlite3_str_errcode(sqlite3_str*);
8678SQLITE_API int sqlite3_str_length(sqlite3_str*);
8679SQLITE_API char *sqlite3_str_value(sqlite3_str*);
8680
8681/*
8682** CAPI3REF: SQLite Runtime Status
8683**
8684** ^These interfaces are used to retrieve runtime status information
8685** about the performance of SQLite, and optionally to reset various
8686** highwater marks. ^The first argument is an integer code for
8687** the specific parameter to measure. ^(Recognized integer codes
8688** are of the form [status parameters | SQLITE_STATUS_...].)^
8689** ^The current value of the parameter is returned into *pCurrent.
8690** ^The highest recorded value is returned in *pHighwater. ^If the
8691** resetFlag is true, then the highest record value is reset after
8692** *pHighwater is written. ^(Some parameters do not record the highest
8693** value. For those parameters
8694** nothing is written into *pHighwater and the resetFlag is ignored.)^
8695** ^(Other parameters record only the highwater mark and not the current
8696** value. For these latter parameters nothing is written into *pCurrent.)^
8697**
8698** ^The sqlite3_status() and sqlite3_status64() routines return
8699** SQLITE_OK on success and a non-zero [error code] on failure.
8700**
8701** If either the current value or the highwater mark is too large to
8702** be represented by a 32-bit integer, then the values returned by
8703** sqlite3_status() are undefined.
8704**
8705** See also: [sqlite3_db_status()]
8706*/
8707SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
8708SQLITE_API int sqlite3_status64(
8709 int op,
8710 sqlite3_int64 *pCurrent,
8711 sqlite3_int64 *pHighwater,
8712 int resetFlag
8713);
8714
8715
8716/*
8717** CAPI3REF: Status Parameters
8718** KEYWORDS: {status parameters}
8719**
8720** These integer constants designate various run-time status parameters
8721** that can be returned by [sqlite3_status()].
8722**
8723** <dl>
8724** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
8725** <dd>This parameter is the current amount of memory checked out
8726** using [sqlite3_malloc()], either directly or indirectly. The
8727** figure includes calls made to [sqlite3_malloc()] by the application
8728** and internal memory usage by the SQLite library. Auxiliary page-cache
8729** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
8730** this parameter. The amount returned is the sum of the allocation
8731** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
8732**
8733** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
8734** <dd>This parameter records the largest memory allocation request
8735** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
8736** internal equivalents). Only the value returned in the
8737** *pHighwater parameter to [sqlite3_status()] is of interest.
8738** The value written into the *pCurrent parameter is undefined.</dd>)^
8739**
8740** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
8741** <dd>This parameter records the number of separate memory allocations
8742** currently checked out.</dd>)^
8743**
8744** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
8745** <dd>This parameter returns the number of pages used out of the
8746** [pagecache memory allocator] that was configured using
8747** [SQLITE_CONFIG_PAGECACHE]. The
8748** value returned is in pages, not in bytes.</dd>)^
8749**
8750** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
8751** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
8752** <dd>This parameter returns the number of bytes of page cache
8753** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
8754** buffer and where forced to overflow to [sqlite3_malloc()]. The
8755** returned value includes allocations that overflowed because they
8756** where too large (they were larger than the "sz" parameter to
8757** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
8758** no space was left in the page cache.</dd>)^
8759**
8760** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
8761** <dd>This parameter records the largest memory allocation request
8762** handed to the [pagecache memory allocator]. Only the value returned in the
8763** *pHighwater parameter to [sqlite3_status()] is of interest.
8764** The value written into the *pCurrent parameter is undefined.</dd>)^
8765**
8766** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt>
8767** <dd>No longer used.</dd>
8768**
8769** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
8770** <dd>No longer used.</dd>
8771**
8772** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
8773** <dd>No longer used.</dd>
8774**
8775** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
8776** <dd>The *pHighwater parameter records the deepest parser stack.
8777** The *pCurrent value is undefined. The *pHighwater value is only
8778** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
8779** </dl>
8780**
8781** New status parameters may be added from time to time.
8782*/
8783#define SQLITE_STATUS_MEMORY_USED 0
8784#define SQLITE_STATUS_PAGECACHE_USED 1
8785#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
8786#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */
8787#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */
8788#define SQLITE_STATUS_MALLOC_SIZE 5
8789#define SQLITE_STATUS_PARSER_STACK 6
8790#define SQLITE_STATUS_PAGECACHE_SIZE 7
8791#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */
8792#define SQLITE_STATUS_MALLOC_COUNT 9
8793
8794/*
8795** CAPI3REF: Database Connection Status
8796** METHOD: sqlite3
8797**
8798** ^This interface is used to retrieve runtime status information
8799** about a single [database connection]. ^The first argument is the
8800** database connection object to be interrogated. ^The second argument
8801** is an integer constant, taken from the set of
8802** [SQLITE_DBSTATUS options], that
8803** determines the parameter to interrogate. The set of
8804** [SQLITE_DBSTATUS options] is likely
8805** to grow in future releases of SQLite.
8806**
8807** ^The current value of the requested parameter is written into *pCur
8808** and the highest instantaneous value is written into *pHiwtr. ^If
8809** the resetFlg is true, then the highest instantaneous value is
8810** reset back down to the current value.
8811**
8812** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
8813** non-zero [error code] on failure.
8814**
8815** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
8816*/
8817SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
8818
8819/*
8820** CAPI3REF: Status Parameters for database connections
8821** KEYWORDS: {SQLITE_DBSTATUS options}
8822**
8823** These constants are the available integer "verbs" that can be passed as
8824** the second argument to the [sqlite3_db_status()] interface.
8825**
8826** New verbs may be added in future releases of SQLite. Existing verbs
8827** might be discontinued. Applications should check the return code from
8828** [sqlite3_db_status()] to make sure that the call worked.
8829** The [sqlite3_db_status()] interface will return a non-zero error code
8830** if a discontinued or unsupported verb is invoked.
8831**
8832** <dl>
8833** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
8834** <dd>This parameter returns the number of lookaside memory slots currently
8835** checked out.</dd>)^
8836**
8837** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
8838** <dd>This parameter returns the number of malloc attempts that were
8839** satisfied using lookaside memory. Only the high-water value is meaningful;
8840** the current value is always zero.)^
8841**
8842** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
8843** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
8844** <dd>This parameter returns the number malloc attempts that might have
8845** been satisfied using lookaside memory but failed due to the amount of
8846** memory requested being larger than the lookaside slot size.
8847** Only the high-water value is meaningful;
8848** the current value is always zero.)^
8849**
8850** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
8851** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
8852** <dd>This parameter returns the number malloc attempts that might have
8853** been satisfied using lookaside memory but failed due to all lookaside
8854** memory already being in use.
8855** Only the high-water value is meaningful;
8856** the current value is always zero.)^
8857**
8858** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
8859** <dd>This parameter returns the approximate number of bytes of heap
8860** memory used by all pager caches associated with the database connection.)^
8861** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
8862**
8863** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]]
8864** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
8865** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
8866** pager cache is shared between two or more connections the bytes of heap
8867** memory used by that pager cache is divided evenly between the attached
8868** connections.)^ In other words, if none of the pager caches associated
8869** with the database connection are shared, this request returns the same
8870** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
8871** shared, the value returned by this call will be smaller than that returned
8872** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
8873** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.
8874**
8875** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
8876** <dd>This parameter returns the approximate number of bytes of heap
8877** memory used to store the schema for all databases associated
8878** with the connection - main, temp, and any [ATTACH]-ed databases.)^
8879** ^The full amount of memory used by the schemas is reported, even if the
8880** schema memory is shared with other database connections due to
8881** [shared cache mode] being enabled.
8882** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
8883**
8884** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
8885** <dd>This parameter returns the approximate number of bytes of heap
8886** and lookaside memory used by all prepared statements associated with
8887** the database connection.)^
8888** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
8889** </dd>
8890**
8891** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
8892** <dd>This parameter returns the number of pager cache hits that have
8893** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
8894** is always 0.
8895** </dd>
8896**
8897** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
8898** <dd>This parameter returns the number of pager cache misses that have
8899** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
8900** is always 0.
8901** </dd>
8902**
8903** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
8904** <dd>This parameter returns the number of dirty cache entries that have
8905** been written to disk. Specifically, the number of pages written to the
8906** wal file in wal mode databases, or the number of pages written to the
8907** database file in rollback mode databases. Any pages written as part of
8908** transaction rollback or database recovery operations are not included.
8909** If an IO or other error occurs while writing a page to disk, the effect
8910** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
8911** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
8912** </dd>
8913**
8914** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt>
8915** <dd>This parameter returns the number of dirty cache entries that have
8916** been written to disk in the middle of a transaction due to the page
8917** cache overflowing. Transactions are more efficient if they are written
8918** to disk all at once. When pages spill mid-transaction, that introduces
8919** additional overhead. This parameter can be used help identify
8920** inefficiencies that can be resolved by increasing the cache size.
8921** </dd>
8922**
8923** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
8924** <dd>This parameter returns zero for the current value if and only if
8925** all foreign key constraints (deferred or immediate) have been
8926** resolved.)^ ^The highwater mark is always 0.
8927** </dd>
8928** </dl>
8929*/
8930#define SQLITE_DBSTATUS_LOOKASIDE_USED 0
8931#define SQLITE_DBSTATUS_CACHE_USED 1
8932#define SQLITE_DBSTATUS_SCHEMA_USED 2
8933#define SQLITE_DBSTATUS_STMT_USED 3
8934#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
8935#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
8936#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
8937#define SQLITE_DBSTATUS_CACHE_HIT 7
8938#define SQLITE_DBSTATUS_CACHE_MISS 8
8939#define SQLITE_DBSTATUS_CACHE_WRITE 9
8940#define SQLITE_DBSTATUS_DEFERRED_FKS 10
8941#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11
8942#define SQLITE_DBSTATUS_CACHE_SPILL 12
8943#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */
8944
8945
8946/*
8947** CAPI3REF: Prepared Statement Status
8948** METHOD: sqlite3_stmt
8949**
8950** ^(Each prepared statement maintains various
8951** [SQLITE_STMTSTATUS counters] that measure the number
8952** of times it has performed specific operations.)^ These counters can
8953** be used to monitor the performance characteristics of the prepared
8954** statements. For example, if the number of table steps greatly exceeds
8955** the number of table searches or result rows, that would tend to indicate
8956** that the prepared statement is using a full table scan rather than
8957** an index.
8958**
8959** ^(This interface is used to retrieve and reset counter values from
8960** a [prepared statement]. The first argument is the prepared statement
8961** object to be interrogated. The second argument
8962** is an integer code for a specific [SQLITE_STMTSTATUS counter]
8963** to be interrogated.)^
8964** ^The current value of the requested counter is returned.
8965** ^If the resetFlg is true, then the counter is reset to zero after this
8966** interface call returns.
8967**
8968** See also: [sqlite3_status()] and [sqlite3_db_status()].
8969*/
8970SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
8971
8972/*
8973** CAPI3REF: Status Parameters for prepared statements
8974** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
8975**
8976** These preprocessor macros define integer codes that name counter
8977** values associated with the [sqlite3_stmt_status()] interface.
8978** The meanings of the various counters are as follows:
8979**
8980** <dl>
8981** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
8982** <dd>^This is the number of times that SQLite has stepped forward in
8983** a table as part of a full table scan. Large numbers for this counter
8984** may indicate opportunities for performance improvement through
8985** careful use of indices.</dd>
8986**
8987** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
8988** <dd>^This is the number of sort operations that have occurred.
8989** A non-zero value in this counter may indicate an opportunity to
8990** improvement performance through careful use of indices.</dd>
8991**
8992** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
8993** <dd>^This is the number of rows inserted into transient indices that
8994** were created automatically in order to help joins run faster.
8995** A non-zero value in this counter may indicate an opportunity to
8996** improvement performance by adding permanent indices that do not
8997** need to be reinitialized each time the statement is run.</dd>
8998**
8999** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
9000** <dd>^This is the number of virtual machine operations executed
9001** by the prepared statement if that number is less than or equal
9002** to 2147483647. The number of virtual machine operations can be
9003** used as a proxy for the total work done by the prepared statement.
9004** If the number of virtual machine operations exceeds 2147483647
9005** then the value returned by this statement status code is undefined.
9006**
9007** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt>
9008** <dd>^This is the number of times that the prepare statement has been
9009** automatically regenerated due to schema changes or changes to
9010** [bound parameters] that might affect the query plan.
9011**
9012** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt>
9013** <dd>^This is the number of times that the prepared statement has
9014** been run. A single "run" for the purposes of this counter is one
9015** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
9016** The counter is incremented on the first [sqlite3_step()] call of each
9017** cycle.
9018**
9019** [[SQLITE_STMTSTATUS_FILTER_MISS]]
9020** [[SQLITE_STMTSTATUS_FILTER HIT]]
9021** <dt>SQLITE_STMTSTATUS_FILTER_HIT<br>
9022** SQLITE_STMTSTATUS_FILTER_MISS</dt>
9023** <dd>^SQLITE_STMTSTATUS_FILTER_HIT is the number of times that a join
9024** step was bypassed because a Bloom filter returned not-found. The
9025** corresponding SQLITE_STMTSTATUS_FILTER_MISS value is the number of
9026** times that the Bloom filter returned a find, and thus the join step
9027** had to be processed as normal.
9028**
9029** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt>
9030** <dd>^This is the approximate number of bytes of heap memory
9031** used to store the prepared statement. ^This value is not actually
9032** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
9033** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
9034** </dd>
9035** </dl>
9036*/
9037#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
9038#define SQLITE_STMTSTATUS_SORT 2
9039#define SQLITE_STMTSTATUS_AUTOINDEX 3
9040#define SQLITE_STMTSTATUS_VM_STEP 4
9041#define SQLITE_STMTSTATUS_REPREPARE 5
9042#define SQLITE_STMTSTATUS_RUN 6
9043#define SQLITE_STMTSTATUS_FILTER_MISS 7
9044#define SQLITE_STMTSTATUS_FILTER_HIT 8
9045#define SQLITE_STMTSTATUS_MEMUSED 99
9046
9047/*
9048** CAPI3REF: Custom Page Cache Object
9049**
9050** The sqlite3_pcache type is opaque. It is implemented by
9051** the pluggable module. The SQLite core has no knowledge of
9052** its size or internal structure and never deals with the
9053** sqlite3_pcache object except by holding and passing pointers
9054** to the object.
9055**
9056** See [sqlite3_pcache_methods2] for additional information.
9057*/
9058typedef struct sqlite3_pcache sqlite3_pcache;
9059
9060/*
9061** CAPI3REF: Custom Page Cache Object
9062**
9063** The sqlite3_pcache_page object represents a single page in the
9064** page cache. The page cache will allocate instances of this
9065** object. Various methods of the page cache use pointers to instances
9066** of this object as parameters or as their return value.
9067**
9068** See [sqlite3_pcache_methods2] for additional information.
9069*/
9070typedef struct sqlite3_pcache_page sqlite3_pcache_page;
9071struct sqlite3_pcache_page {
9072 void *pBuf; /* The content of the page */
9073 void *pExtra; /* Extra information associated with the page */
9074};
9075
9076/*
9077** CAPI3REF: Application Defined Page Cache.
9078** KEYWORDS: {page cache}
9079**
9080** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
9081** register an alternative page cache implementation by passing in an
9082** instance of the sqlite3_pcache_methods2 structure.)^
9083** In many applications, most of the heap memory allocated by
9084** SQLite is used for the page cache.
9085** By implementing a
9086** custom page cache using this API, an application can better control
9087** the amount of memory consumed by SQLite, the way in which
9088** that memory is allocated and released, and the policies used to
9089** determine exactly which parts of a database file are cached and for
9090** how long.
9091**
9092** The alternative page cache mechanism is an
9093** extreme measure that is only needed by the most demanding applications.
9094** The built-in page cache is recommended for most uses.
9095**
9096** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
9097** internal buffer by SQLite within the call to [sqlite3_config]. Hence
9098** the application may discard the parameter after the call to
9099** [sqlite3_config()] returns.)^
9100**
9101** [[the xInit() page cache method]]
9102** ^(The xInit() method is called once for each effective
9103** call to [sqlite3_initialize()])^
9104** (usually only once during the lifetime of the process). ^(The xInit()
9105** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
9106** The intent of the xInit() method is to set up global data structures
9107** required by the custom page cache implementation.
9108** ^(If the xInit() method is NULL, then the
9109** built-in default page cache is used instead of the application defined
9110** page cache.)^
9111**
9112** [[the xShutdown() page cache method]]
9113** ^The xShutdown() method is called by [sqlite3_shutdown()].
9114** It can be used to clean up
9115** any outstanding resources before process shutdown, if required.
9116** ^The xShutdown() method may be NULL.
9117**
9118** ^SQLite automatically serializes calls to the xInit method,
9119** so the xInit method need not be threadsafe. ^The
9120** xShutdown method is only called from [sqlite3_shutdown()] so it does
9121** not need to be threadsafe either. All other methods must be threadsafe
9122** in multithreaded applications.
9123**
9124** ^SQLite will never invoke xInit() more than once without an intervening
9125** call to xShutdown().
9126**
9127** [[the xCreate() page cache methods]]
9128** ^SQLite invokes the xCreate() method to construct a new cache instance.
9129** SQLite will typically create one cache instance for each open database file,
9130** though this is not guaranteed. ^The
9131** first parameter, szPage, is the size in bytes of the pages that must
9132** be allocated by the cache. ^szPage will always a power of two. ^The
9133** second parameter szExtra is a number of bytes of extra storage
9134** associated with each page cache entry. ^The szExtra parameter will
9135** a number less than 250. SQLite will use the
9136** extra szExtra bytes on each page to store metadata about the underlying
9137** database page on disk. The value passed into szExtra depends
9138** on the SQLite version, the target platform, and how SQLite was compiled.
9139** ^The third argument to xCreate(), bPurgeable, is true if the cache being
9140** created will be used to cache database pages of a file stored on disk, or
9141** false if it is used for an in-memory database. The cache implementation
9142** does not have to do anything special based with the value of bPurgeable;
9143** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will
9144** never invoke xUnpin() except to deliberately delete a page.
9145** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
9146** false will always have the "discard" flag set to true.
9147** ^Hence, a cache created with bPurgeable false will
9148** never contain any unpinned pages.
9149**
9150** [[the xCachesize() page cache method]]
9151** ^(The xCachesize() method may be called at any time by SQLite to set the
9152** suggested maximum cache-size (number of pages stored by) the cache
9153** instance passed as the first argument. This is the value configured using
9154** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable
9155** parameter, the implementation is not required to do anything with this
9156** value; it is advisory only.
9157**
9158** [[the xPagecount() page cache methods]]
9159** The xPagecount() method must return the number of pages currently
9160** stored in the cache, both pinned and unpinned.
9161**
9162** [[the xFetch() page cache methods]]
9163** The xFetch() method locates a page in the cache and returns a pointer to
9164** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
9165** The pBuf element of the returned sqlite3_pcache_page object will be a
9166** pointer to a buffer of szPage bytes used to store the content of a
9167** single database page. The pExtra element of sqlite3_pcache_page will be
9168** a pointer to the szExtra bytes of extra storage that SQLite has requested
9169** for each entry in the page cache.
9170**
9171** The page to be fetched is determined by the key. ^The minimum key value
9172** is 1. After it has been retrieved using xFetch, the page is considered
9173** to be "pinned".
9174**
9175** If the requested page is already in the page cache, then the page cache
9176** implementation must return a pointer to the page buffer with its content
9177** intact. If the requested page is not already in the cache, then the
9178** cache implementation should use the value of the createFlag
9179** parameter to help it determined what action to take:
9180**
9181** <table border=1 width=85% align=center>
9182** <tr><th> createFlag <th> Behavior when page is not already in cache
9183** <tr><td> 0 <td> Do not allocate a new page. Return NULL.
9184** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
9185** Otherwise return NULL.
9186** <tr><td> 2 <td> Make every effort to allocate a new page. Only return
9187** NULL if allocating a new page is effectively impossible.
9188** </table>
9189**
9190** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
9191** will only use a createFlag of 2 after a prior call with a createFlag of 1
9192** failed.)^ In between the xFetch() calls, SQLite may
9193** attempt to unpin one or more cache pages by spilling the content of
9194** pinned pages to disk and synching the operating system disk cache.
9195**
9196** [[the xUnpin() page cache method]]
9197** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
9198** as its second argument. If the third parameter, discard, is non-zero,
9199** then the page must be evicted from the cache.
9200** ^If the discard parameter is
9201** zero, then the page may be discarded or retained at the discretion of
9202** page cache implementation. ^The page cache implementation
9203** may choose to evict unpinned pages at any time.
9204**
9205** The cache must not perform any reference counting. A single
9206** call to xUnpin() unpins the page regardless of the number of prior calls
9207** to xFetch().
9208**
9209** [[the xRekey() page cache methods]]
9210** The xRekey() method is used to change the key value associated with the
9211** page passed as the second argument. If the cache
9212** previously contains an entry associated with newKey, it must be
9213** discarded. ^Any prior cache entry associated with newKey is guaranteed not
9214** to be pinned.
9215**
9216** When SQLite calls the xTruncate() method, the cache must discard all
9217** existing cache entries with page numbers (keys) greater than or equal
9218** to the value of the iLimit parameter passed to xTruncate(). If any
9219** of these pages are pinned, they are implicitly unpinned, meaning that
9220** they can be safely discarded.
9221**
9222** [[the xDestroy() page cache method]]
9223** ^The xDestroy() method is used to delete a cache allocated by xCreate().
9224** All resources associated with the specified cache should be freed. ^After
9225** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
9226** handle invalid, and will not use it with any other sqlite3_pcache_methods2
9227** functions.
9228**
9229** [[the xShrink() page cache method]]
9230** ^SQLite invokes the xShrink() method when it wants the page cache to
9231** free up as much of heap memory as possible. The page cache implementation
9232** is not obligated to free any memory, but well-behaved implementations should
9233** do their best.
9234*/
9235typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
9236struct sqlite3_pcache_methods2 {
9237 int iVersion;
9238 void *pArg;
9239 int (*xInit)(void*);
9240 void (*xShutdown)(void*);
9241 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
9242 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
9243 int (*xPagecount)(sqlite3_pcache*);
9244 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
9245 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
9246 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
9247 unsigned oldKey, unsigned newKey);
9248 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
9249 void (*xDestroy)(sqlite3_pcache*);
9250 void (*xShrink)(sqlite3_pcache*);
9251};
9252
9253/*
9254** This is the obsolete pcache_methods object that has now been replaced
9255** by sqlite3_pcache_methods2. This object is not used by SQLite. It is
9256** retained in the header file for backwards compatibility only.
9257*/
9258typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
9259struct sqlite3_pcache_methods {
9260 void *pArg;
9261 int (*xInit)(void*);
9262 void (*xShutdown)(void*);
9263 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
9264 void (*xCachesize)(sqlite3_pcache*, int nCachesize);
9265 int (*xPagecount)(sqlite3_pcache*);
9266 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
9267 void (*xUnpin)(sqlite3_pcache*, void*, int discard);
9268 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
9269 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
9270 void (*xDestroy)(sqlite3_pcache*);
9271};
9272
9273
9274/*
9275** CAPI3REF: Online Backup Object
9276**
9277** The sqlite3_backup object records state information about an ongoing
9278** online backup operation. ^The sqlite3_backup object is created by
9279** a call to [sqlite3_backup_init()] and is destroyed by a call to
9280** [sqlite3_backup_finish()].
9281**
9282** See Also: [Using the SQLite Online Backup API]
9283*/
9284typedef struct sqlite3_backup sqlite3_backup;
9285
9286/*
9287** CAPI3REF: Online Backup API.
9288**
9289** The backup API copies the content of one database into another.
9290** It is useful either for creating backups of databases or
9291** for copying in-memory databases to or from persistent files.
9292**
9293** See Also: [Using the SQLite Online Backup API]
9294**
9295** ^SQLite holds a write transaction open on the destination database file
9296** for the duration of the backup operation.
9297** ^The source database is read-locked only while it is being read;
9298** it is not locked continuously for the entire backup operation.
9299** ^Thus, the backup may be performed on a live source database without
9300** preventing other database connections from
9301** reading or writing to the source database while the backup is underway.
9302**
9303** ^(To perform a backup operation:
9304** <ol>
9305** <li><b>sqlite3_backup_init()</b> is called once to initialize the
9306** backup,
9307** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
9308** the data between the two databases, and finally
9309** <li><b>sqlite3_backup_finish()</b> is called to release all resources
9310** associated with the backup operation.
9311** </ol>)^
9312** There should be exactly one call to sqlite3_backup_finish() for each
9313** successful call to sqlite3_backup_init().
9314**
9315** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
9316**
9317** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
9318** [database connection] associated with the destination database
9319** and the database name, respectively.
9320** ^The database name is "main" for the main database, "temp" for the
9321** temporary database, or the name specified after the AS keyword in
9322** an [ATTACH] statement for an attached database.
9323** ^The S and M arguments passed to
9324** sqlite3_backup_init(D,N,S,M) identify the [database connection]
9325** and database name of the source database, respectively.
9326** ^The source and destination [database connections] (parameters S and D)
9327** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
9328** an error.
9329**
9330** ^A call to sqlite3_backup_init() will fail, returning NULL, if
9331** there is already a read or read-write transaction open on the
9332** destination database.
9333**
9334** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
9335** returned and an error code and error message are stored in the
9336** destination [database connection] D.
9337** ^The error code and message for the failed call to sqlite3_backup_init()
9338** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
9339** [sqlite3_errmsg16()] functions.
9340** ^A successful call to sqlite3_backup_init() returns a pointer to an
9341** [sqlite3_backup] object.
9342** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
9343** sqlite3_backup_finish() functions to perform the specified backup
9344** operation.
9345**
9346** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
9347**
9348** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
9349** the source and destination databases specified by [sqlite3_backup] object B.
9350** ^If N is negative, all remaining source pages are copied.
9351** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
9352** are still more pages to be copied, then the function returns [SQLITE_OK].
9353** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
9354** from source to destination, then it returns [SQLITE_DONE].
9355** ^If an error occurs while running sqlite3_backup_step(B,N),
9356** then an [error code] is returned. ^As well as [SQLITE_OK] and
9357** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
9358** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
9359** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
9360**
9361** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
9362** <ol>
9363** <li> the destination database was opened read-only, or
9364** <li> the destination database is using write-ahead-log journaling
9365** and the destination and source page sizes differ, or
9366** <li> the destination database is an in-memory database and the
9367** destination and source page sizes differ.
9368** </ol>)^
9369**
9370** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
9371** the [sqlite3_busy_handler | busy-handler function]
9372** is invoked (if one is specified). ^If the
9373** busy-handler returns non-zero before the lock is available, then
9374** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
9375** sqlite3_backup_step() can be retried later. ^If the source
9376** [database connection]
9377** is being used to write to the source database when sqlite3_backup_step()
9378** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
9379** case the call to sqlite3_backup_step() can be retried later on. ^(If
9380** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
9381** [SQLITE_READONLY] is returned, then
9382** there is no point in retrying the call to sqlite3_backup_step(). These
9383** errors are considered fatal.)^ The application must accept
9384** that the backup operation has failed and pass the backup operation handle
9385** to the sqlite3_backup_finish() to release associated resources.
9386**
9387** ^The first call to sqlite3_backup_step() obtains an exclusive lock
9388** on the destination file. ^The exclusive lock is not released until either
9389** sqlite3_backup_finish() is called or the backup operation is complete
9390** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to
9391** sqlite3_backup_step() obtains a [shared lock] on the source database that
9392** lasts for the duration of the sqlite3_backup_step() call.
9393** ^Because the source database is not locked between calls to
9394** sqlite3_backup_step(), the source database may be modified mid-way
9395** through the backup process. ^If the source database is modified by an
9396** external process or via a database connection other than the one being
9397** used by the backup operation, then the backup will be automatically
9398** restarted by the next call to sqlite3_backup_step(). ^If the source
9399** database is modified by the using the same database connection as is used
9400** by the backup operation, then the backup database is automatically
9401** updated at the same time.
9402**
9403** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
9404**
9405** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
9406** application wishes to abandon the backup operation, the application
9407** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
9408** ^The sqlite3_backup_finish() interfaces releases all
9409** resources associated with the [sqlite3_backup] object.
9410** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
9411** active write-transaction on the destination database is rolled back.
9412** The [sqlite3_backup] object is invalid
9413** and may not be used following a call to sqlite3_backup_finish().
9414**
9415** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
9416** sqlite3_backup_step() errors occurred, regardless or whether or not
9417** sqlite3_backup_step() completed.
9418** ^If an out-of-memory condition or IO error occurred during any prior
9419** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
9420** sqlite3_backup_finish() returns the corresponding [error code].
9421**
9422** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
9423** is not a permanent error and does not affect the return value of
9424** sqlite3_backup_finish().
9425**
9426** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
9427** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
9428**
9429** ^The sqlite3_backup_remaining() routine returns the number of pages still
9430** to be backed up at the conclusion of the most recent sqlite3_backup_step().
9431** ^The sqlite3_backup_pagecount() routine returns the total number of pages
9432** in the source database at the conclusion of the most recent
9433** sqlite3_backup_step().
9434** ^(The values returned by these functions are only updated by
9435** sqlite3_backup_step(). If the source database is modified in a way that
9436** changes the size of the source database or the number of pages remaining,
9437** those changes are not reflected in the output of sqlite3_backup_pagecount()
9438** and sqlite3_backup_remaining() until after the next
9439** sqlite3_backup_step().)^
9440**
9441** <b>Concurrent Usage of Database Handles</b>
9442**
9443** ^The source [database connection] may be used by the application for other
9444** purposes while a backup operation is underway or being initialized.
9445** ^If SQLite is compiled and configured to support threadsafe database
9446** connections, then the source database connection may be used concurrently
9447** from within other threads.
9448**
9449** However, the application must guarantee that the destination
9450** [database connection] is not passed to any other API (by any thread) after
9451** sqlite3_backup_init() is called and before the corresponding call to
9452** sqlite3_backup_finish(). SQLite does not currently check to see
9453** if the application incorrectly accesses the destination [database connection]
9454** and so no error code is reported, but the operations may malfunction
9455** nevertheless. Use of the destination database connection while a
9456** backup is in progress might also cause a mutex deadlock.
9457**
9458** If running in [shared cache mode], the application must
9459** guarantee that the shared cache used by the destination database
9460** is not accessed while the backup is running. In practice this means
9461** that the application must guarantee that the disk file being
9462** backed up to is not accessed by any connection within the process,
9463** not just the specific connection that was passed to sqlite3_backup_init().
9464**
9465** The [sqlite3_backup] object itself is partially threadsafe. Multiple
9466** threads may safely make multiple concurrent calls to sqlite3_backup_step().
9467** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
9468** APIs are not strictly speaking threadsafe. If they are invoked at the
9469** same time as another thread is invoking sqlite3_backup_step() it is
9470** possible that they return invalid values.
9471**
9472** <b>Alternatives To Using The Backup API</b>
9473**
9474** Other techniques for safely creating a consistent backup of an SQLite
9475** database include:
9476**
9477** <ul>
9478** <li> The [VACUUM INTO] command.
9479** <li> The [sqlite3_rsync] utility program.
9480** </ul>
9481*/
9482SQLITE_API sqlite3_backup *sqlite3_backup_init(
9483 sqlite3 *pDest, /* Destination database handle */
9484 const char *zDestName, /* Destination database name */
9485 sqlite3 *pSource, /* Source database handle */
9486 const char *zSourceName /* Source database name */
9487);
9488SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
9489SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
9490SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
9491SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
9492
9493/*
9494** CAPI3REF: Unlock Notification
9495** METHOD: sqlite3
9496**
9497** ^When running in shared-cache mode, a database operation may fail with
9498** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
9499** individual tables within the shared-cache cannot be obtained. See
9500** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
9501** ^This API may be used to register a callback that SQLite will invoke
9502** when the connection currently holding the required lock relinquishes it.
9503** ^This API is only available if the library was compiled with the
9504** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
9505**
9506** See Also: [Using the SQLite Unlock Notification Feature].
9507**
9508** ^Shared-cache locks are released when a database connection concludes
9509** its current transaction, either by committing it or rolling it back.
9510**
9511** ^When a connection (known as the blocked connection) fails to obtain a
9512** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
9513** identity of the database connection (the blocking connection) that
9514** has locked the required resource is stored internally. ^After an
9515** application receives an SQLITE_LOCKED error, it may call the
9516** sqlite3_unlock_notify() method with the blocked connection handle as
9517** the first argument to register for a callback that will be invoked
9518** when the blocking connections current transaction is concluded. ^The
9519** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
9520** call that concludes the blocking connection's transaction.
9521**
9522** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
9523** there is a chance that the blocking connection will have already
9524** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
9525** If this happens, then the specified callback is invoked immediately,
9526** from within the call to sqlite3_unlock_notify().)^
9527**
9528** ^If the blocked connection is attempting to obtain a write-lock on a
9529** shared-cache table, and more than one other connection currently holds
9530** a read-lock on the same table, then SQLite arbitrarily selects one of
9531** the other connections to use as the blocking connection.
9532**
9533** ^(There may be at most one unlock-notify callback registered by a
9534** blocked connection. If sqlite3_unlock_notify() is called when the
9535** blocked connection already has a registered unlock-notify callback,
9536** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
9537** called with a NULL pointer as its second argument, then any existing
9538** unlock-notify callback is canceled. ^The blocked connections
9539** unlock-notify callback may also be canceled by closing the blocked
9540** connection using [sqlite3_close()].
9541**
9542** The unlock-notify callback is not reentrant. If an application invokes
9543** any sqlite3_xxx API functions from within an unlock-notify callback, a
9544** crash or deadlock may be the result.
9545**
9546** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
9547** returns SQLITE_OK.
9548**
9549** <b>Callback Invocation Details</b>
9550**
9551** When an unlock-notify callback is registered, the application provides a
9552** single void* pointer that is passed to the callback when it is invoked.
9553** However, the signature of the callback function allows SQLite to pass
9554** it an array of void* context pointers. The first argument passed to
9555** an unlock-notify callback is a pointer to an array of void* pointers,
9556** and the second is the number of entries in the array.
9557**
9558** When a blocking connection's transaction is concluded, there may be
9559** more than one blocked connection that has registered for an unlock-notify
9560** callback. ^If two or more such blocked connections have specified the
9561** same callback function, then instead of invoking the callback function
9562** multiple times, it is invoked once with the set of void* context pointers
9563** specified by the blocked connections bundled together into an array.
9564** This gives the application an opportunity to prioritize any actions
9565** related to the set of unblocked database connections.
9566**
9567** <b>Deadlock Detection</b>
9568**
9569** Assuming that after registering for an unlock-notify callback a
9570** database waits for the callback to be issued before taking any further
9571** action (a reasonable assumption), then using this API may cause the
9572** application to deadlock. For example, if connection X is waiting for
9573** connection Y's transaction to be concluded, and similarly connection
9574** Y is waiting on connection X's transaction, then neither connection
9575** will proceed and the system may remain deadlocked indefinitely.
9576**
9577** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
9578** detection. ^If a given call to sqlite3_unlock_notify() would put the
9579** system in a deadlocked state, then SQLITE_LOCKED is returned and no
9580** unlock-notify callback is registered. The system is said to be in
9581** a deadlocked state if connection A has registered for an unlock-notify
9582** callback on the conclusion of connection B's transaction, and connection
9583** B has itself registered for an unlock-notify callback when connection
9584** A's transaction is concluded. ^Indirect deadlock is also detected, so
9585** the system is also considered to be deadlocked if connection B has
9586** registered for an unlock-notify callback on the conclusion of connection
9587** C's transaction, where connection C is waiting on connection A. ^Any
9588** number of levels of indirection are allowed.
9589**
9590** <b>The "DROP TABLE" Exception</b>
9591**
9592** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
9593** always appropriate to call sqlite3_unlock_notify(). There is however,
9594** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
9595** SQLite checks if there are any currently executing SELECT statements
9596** that belong to the same connection. If there are, SQLITE_LOCKED is
9597** returned. In this case there is no "blocking connection", so invoking
9598** sqlite3_unlock_notify() results in the unlock-notify callback being
9599** invoked immediately. If the application then re-attempts the "DROP TABLE"
9600** or "DROP INDEX" query, an infinite loop might be the result.
9601**
9602** One way around this problem is to check the extended error code returned
9603** by an sqlite3_step() call. ^(If there is a blocking connection, then the
9604** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
9605** the special "DROP TABLE/INDEX" case, the extended error code is just
9606** SQLITE_LOCKED.)^
9607*/
9608SQLITE_API int sqlite3_unlock_notify(
9609 sqlite3 *pBlocked, /* Waiting connection */
9610 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
9611 void *pNotifyArg /* Argument to pass to xNotify */
9612);
9613
9614
9615/*
9616** CAPI3REF: String Comparison
9617**
9618** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
9619** and extensions to compare the contents of two buffers containing UTF-8
9620** strings in a case-independent fashion, using the same definition of "case
9621** independence" that SQLite uses internally when comparing identifiers.
9622*/
9623SQLITE_API int sqlite3_stricmp(const char *, const char *);
9624SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
9625
9626/*
9627** CAPI3REF: String Globbing
9628*
9629** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
9630** string X matches the [GLOB] pattern P.
9631** ^The definition of [GLOB] pattern matching used in
9632** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
9633** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function
9634** is case sensitive.
9635**
9636** Note that this routine returns zero on a match and non-zero if the strings
9637** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
9638**
9639** See also: [sqlite3_strlike()].
9640*/
9641SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
9642
9643/*
9644** CAPI3REF: String LIKE Matching
9645*
9646** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
9647** string X matches the [LIKE] pattern P with escape character E.
9648** ^The definition of [LIKE] pattern matching used in
9649** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
9650** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without
9651** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
9652** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
9653** insensitive - equivalent upper and lower case ASCII characters match
9654** one another.
9655**
9656** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
9657** only ASCII characters are case folded.
9658**
9659** Note that this routine returns zero on a match and non-zero if the strings
9660** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
9661**
9662** See also: [sqlite3_strglob()].
9663*/
9664SQLITE_API int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
9665
9666/*
9667** CAPI3REF: Error Logging Interface
9668**
9669** ^The [sqlite3_log()] interface writes a message into the [error log]
9670** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
9671** ^If logging is enabled, the zFormat string and subsequent arguments are
9672** used with [sqlite3_snprintf()] to generate the final output string.
9673**
9674** The sqlite3_log() interface is intended for use by extensions such as
9675** virtual tables, collating functions, and SQL functions. While there is
9676** nothing to prevent an application from calling sqlite3_log(), doing so
9677** is considered bad form.
9678**
9679** The zFormat string must not be NULL.
9680**
9681** To avoid deadlocks and other threading problems, the sqlite3_log() routine
9682** will not use dynamically allocated memory. The log message is stored in
9683** a fixed-length buffer on the stack. If the log message is longer than
9684** a few hundred characters, it will be truncated to the length of the
9685** buffer.
9686*/
9687SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
9688
9689/*
9690** CAPI3REF: Write-Ahead Log Commit Hook
9691** METHOD: sqlite3
9692**
9693** ^The [sqlite3_wal_hook()] function is used to register a callback that
9694** is invoked each time data is committed to a database in wal mode.
9695**
9696** ^(The callback is invoked by SQLite after the commit has taken place and
9697** the associated write-lock on the database released)^, so the implementation
9698** may read, write or [checkpoint] the database as required.
9699**
9700** ^The first parameter passed to the callback function when it is invoked
9701** is a copy of the third parameter passed to sqlite3_wal_hook() when
9702** registering the callback. ^The second is a copy of the database handle.
9703** ^The third parameter is the name of the database that was written to -
9704** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
9705** is the number of pages currently in the write-ahead log file,
9706** including those that were just committed.
9707**
9708** The callback function should normally return [SQLITE_OK]. ^If an error
9709** code is returned, that error will propagate back up through the
9710** SQLite code base to cause the statement that provoked the callback
9711** to report an error, though the commit will have still occurred. If the
9712** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
9713** that does not correspond to any valid SQLite error code, the results
9714** are undefined.
9715**
9716** A single database handle may have at most a single write-ahead log callback
9717** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
9718** previously registered write-ahead log callback. ^The return value is
9719** a copy of the third parameter from the previous call, if any, or 0.
9720** ^Note that the [sqlite3_wal_autocheckpoint()] interface and the
9721** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
9722** overwrite any prior [sqlite3_wal_hook()] settings.
9723*/
9724SQLITE_API void *sqlite3_wal_hook(
9725 sqlite3*,
9726 int(*)(void *,sqlite3*,const char*,int),
9727 void*
9728);
9729
9730/*
9731** CAPI3REF: Configure an auto-checkpoint
9732** METHOD: sqlite3
9733**
9734** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
9735** [sqlite3_wal_hook()] that causes any database on [database connection] D
9736** to automatically [checkpoint]
9737** after committing a transaction if there are N or
9738** more frames in the [write-ahead log] file. ^Passing zero or
9739** a negative value as the nFrame parameter disables automatic
9740** checkpoints entirely.
9741**
9742** ^The callback registered by this function replaces any existing callback
9743** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback
9744** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
9745** configured by this function.
9746**
9747** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
9748** from SQL.
9749**
9750** ^Checkpoints initiated by this mechanism are
9751** [sqlite3_wal_checkpoint_v2|PASSIVE].
9752**
9753** ^Every new [database connection] defaults to having the auto-checkpoint
9754** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
9755** pages. The use of this interface
9756** is only necessary if the default setting is found to be suboptimal
9757** for a particular application.
9758*/
9759SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
9760
9761/*
9762** CAPI3REF: Checkpoint a database
9763** METHOD: sqlite3
9764**
9765** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
9766** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
9767**
9768** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
9769** [write-ahead log] for database X on [database connection] D to be
9770** transferred into the database file and for the write-ahead log to
9771** be reset. See the [checkpointing] documentation for addition
9772** information.
9773**
9774** This interface used to be the only way to cause a checkpoint to
9775** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
9776** interface was added. This interface is retained for backwards
9777** compatibility and as a convenience for applications that need to manually
9778** start a callback but which do not need the full power (and corresponding
9779** complication) of [sqlite3_wal_checkpoint_v2()].
9780*/
9781SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
9782
9783/*
9784** CAPI3REF: Checkpoint a database
9785** METHOD: sqlite3
9786**
9787** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
9788** operation on database X of [database connection] D in mode M. Status
9789** information is written back into integers pointed to by L and C.)^
9790** ^(The M parameter must be a valid [checkpoint mode]:)^
9791**
9792** <dl>
9793** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
9794** ^Checkpoint as many frames as possible without waiting for any database
9795** readers or writers to finish, then sync the database file if all frames
9796** in the log were checkpointed. ^The [busy-handler callback]
9797** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
9798** ^On the other hand, passive mode might leave the checkpoint unfinished
9799** if there are concurrent readers or writers.
9800**
9801** <dt>SQLITE_CHECKPOINT_FULL<dd>
9802** ^This mode blocks (it invokes the
9803** [sqlite3_busy_handler|busy-handler callback]) until there is no
9804** database writer and all readers are reading from the most recent database
9805** snapshot. ^It then checkpoints all frames in the log file and syncs the
9806** database file. ^This mode blocks new database writers while it is pending,
9807** but new database readers are allowed to continue unimpeded.
9808**
9809** <dt>SQLITE_CHECKPOINT_RESTART<dd>
9810** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
9811** that after checkpointing the log file it blocks (calls the
9812** [busy-handler callback])
9813** until all readers are reading from the database file only. ^This ensures
9814** that the next writer will restart the log file from the beginning.
9815** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
9816** database writer attempts while it is pending, but does not impede readers.
9817**
9818** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
9819** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
9820** addition that it also truncates the log file to zero bytes just prior
9821** to a successful return.
9822** </dl>
9823**
9824** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
9825** the log file or to -1 if the checkpoint could not run because
9826** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
9827** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
9828** log file (including any that were already checkpointed before the function
9829** was called) or to -1 if the checkpoint could not run due to an error or
9830** because the database is not in WAL mode. ^Note that upon successful
9831** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
9832** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
9833**
9834** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
9835** any other process is running a checkpoint operation at the same time, the
9836** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
9837** busy-handler configured, it will not be invoked in this case.
9838**
9839** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
9840** exclusive "writer" lock on the database file. ^If the writer lock cannot be
9841** obtained immediately, and a busy-handler is configured, it is invoked and
9842** the writer lock retried until either the busy-handler returns 0 or the lock
9843** is successfully obtained. ^The busy-handler is also invoked while waiting for
9844** database readers as described above. ^If the busy-handler returns 0 before
9845** the writer lock is obtained or while waiting for database readers, the
9846** checkpoint operation proceeds from that point in the same way as
9847** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
9848** without blocking any further. ^SQLITE_BUSY is returned in this case.
9849**
9850** ^If parameter zDb is NULL or points to a zero length string, then the
9851** specified operation is attempted on all WAL databases [attached] to
9852** [database connection] db. In this case the
9853** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
9854** an SQLITE_BUSY error is encountered when processing one or more of the
9855** attached WAL databases, the operation is still attempted on any remaining
9856** attached databases and SQLITE_BUSY is returned at the end. ^If any other
9857** error occurs while processing an attached database, processing is abandoned
9858** and the error code is returned to the caller immediately. ^If no error
9859** (SQLITE_BUSY or otherwise) is encountered while processing the attached
9860** databases, SQLITE_OK is returned.
9861**
9862** ^If database zDb is the name of an attached database that is not in WAL
9863** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
9864** zDb is not NULL (or a zero length string) and is not the name of any
9865** attached database, SQLITE_ERROR is returned to the caller.
9866**
9867** ^Unless it returns SQLITE_MISUSE,
9868** the sqlite3_wal_checkpoint_v2() interface
9869** sets the error information that is queried by
9870** [sqlite3_errcode()] and [sqlite3_errmsg()].
9871**
9872** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
9873** from SQL.
9874*/
9875SQLITE_API int sqlite3_wal_checkpoint_v2(
9876 sqlite3 *db, /* Database handle */
9877 const char *zDb, /* Name of attached database (or NULL) */
9878 int eMode, /* SQLITE_CHECKPOINT_* value */
9879 int *pnLog, /* OUT: Size of WAL log in frames */
9880 int *pnCkpt /* OUT: Total number of frames checkpointed */
9881);
9882
9883/*
9884** CAPI3REF: Checkpoint Mode Values
9885** KEYWORDS: {checkpoint mode}
9886**
9887** These constants define all valid values for the "checkpoint mode" passed
9888** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
9889** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
9890** meaning of each of these checkpoint modes.
9891*/
9892#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */
9893#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */
9894#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for readers */
9895#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */
9896
9897/*
9898** CAPI3REF: Virtual Table Interface Configuration
9899**
9900** This function may be called by either the [xConnect] or [xCreate] method
9901** of a [virtual table] implementation to configure
9902** various facets of the virtual table interface.
9903**
9904** If this interface is invoked outside the context of an xConnect or
9905** xCreate virtual table method then the behavior is undefined.
9906**
9907** In the call sqlite3_vtab_config(D,C,...) the D parameter is the
9908** [database connection] in which the virtual table is being created and
9909** which is passed in as the first argument to the [xConnect] or [xCreate]
9910** method that is invoking sqlite3_vtab_config(). The C parameter is one
9911** of the [virtual table configuration options]. The presence and meaning
9912** of parameters after C depend on which [virtual table configuration option]
9913** is used.
9914*/
9915SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
9916
9917/*
9918** CAPI3REF: Virtual Table Configuration Options
9919** KEYWORDS: {virtual table configuration options}
9920** KEYWORDS: {virtual table configuration option}
9921**
9922** These macros define the various options to the
9923** [sqlite3_vtab_config()] interface that [virtual table] implementations
9924** can use to customize and optimize their behavior.
9925**
9926** <dl>
9927** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]]
9928** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt>
9929** <dd>Calls of the form
9930** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
9931** where X is an integer. If X is zero, then the [virtual table] whose
9932** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
9933** support constraints. In this configuration (which is the default) if
9934** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
9935** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
9936** specified as part of the users SQL statement, regardless of the actual
9937** ON CONFLICT mode specified.
9938**
9939** If X is non-zero, then the virtual table implementation guarantees
9940** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
9941** any modifications to internal or persistent data structures have been made.
9942** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
9943** is able to roll back a statement or database transaction, and abandon
9944** or continue processing the current SQL statement as appropriate.
9945** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
9946** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
9947** had been ABORT.
9948**
9949** Virtual table implementations that are required to handle OR REPLACE
9950** must do so within the [xUpdate] method. If a call to the
9951** [sqlite3_vtab_on_conflict()] function indicates that the current ON
9952** CONFLICT policy is REPLACE, the virtual table implementation should
9953** silently replace the appropriate rows within the xUpdate callback and
9954** return SQLITE_OK. Or, if this is not possible, it may return
9955** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
9956** constraint handling.
9957** </dd>
9958**
9959** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt>
9960** <dd>Calls of the form
9961** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the
9962** the [xConnect] or [xCreate] methods of a [virtual table] implementation
9963** prohibits that virtual table from being used from within triggers and
9964** views.
9965** </dd>
9966**
9967** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt>
9968** <dd>Calls of the form
9969** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the
9970** the [xConnect] or [xCreate] methods of a [virtual table] implementation
9971** identify that virtual table as being safe to use from within triggers
9972** and views. Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the
9973** virtual table can do no serious harm even if it is controlled by a
9974** malicious hacker. Developers should avoid setting the SQLITE_VTAB_INNOCUOUS
9975** flag unless absolutely necessary.
9976** </dd>
9977**
9978** [[SQLITE_VTAB_USES_ALL_SCHEMAS]]<dt>SQLITE_VTAB_USES_ALL_SCHEMAS</dt>
9979** <dd>Calls of the form
9980** [sqlite3_vtab_config](db,SQLITE_VTAB_USES_ALL_SCHEMA) from within the
9981** the [xConnect] or [xCreate] methods of a [virtual table] implementation
9982** instruct the query planner to begin at least a read transaction on
9983** all schemas ("main", "temp", and any ATTACH-ed databases) whenever the
9984** virtual table is used.
9985** </dd>
9986** </dl>
9987*/
9988#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
9989#define SQLITE_VTAB_INNOCUOUS 2
9990#define SQLITE_VTAB_DIRECTONLY 3
9991#define SQLITE_VTAB_USES_ALL_SCHEMAS 4
9992
9993/*
9994** CAPI3REF: Determine The Virtual Table Conflict Policy
9995**
9996** This function may only be called from within a call to the [xUpdate] method
9997** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
9998** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
9999** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
10000** of the SQL statement that triggered the call to the [xUpdate] method of the
10001** [virtual table].
10002*/
10003SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
10004
10005/*
10006** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
10007**
10008** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
10009** method of a [virtual table], then it might return true if the
10010** column is being fetched as part of an UPDATE operation during which the
10011** column value will not change. The virtual table implementation can use
10012** this hint as permission to substitute a return value that is less
10013** expensive to compute and that the corresponding
10014** [xUpdate] method understands as a "no-change" value.
10015**
10016** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
10017** the column is not changed by the UPDATE statement, then the xColumn
10018** method can optionally return without setting a result, without calling
10019** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
10020** In that case, [sqlite3_value_nochange(X)] will return true for the
10021** same column in the [xUpdate] method.
10022**
10023** The sqlite3_vtab_nochange() routine is an optimization. Virtual table
10024** implementations should continue to give a correct answer even if the
10025** sqlite3_vtab_nochange() interface were to always return false. In the
10026** current implementation, the sqlite3_vtab_nochange() interface does always
10027** returns false for the enhanced [UPDATE FROM] statement.
10028*/
10029SQLITE_API int sqlite3_vtab_nochange(sqlite3_context*);
10030
10031/*
10032** CAPI3REF: Determine The Collation For a Virtual Table Constraint
10033** METHOD: sqlite3_index_info
10034**
10035** This function may only be called from within a call to the [xBestIndex]
10036** method of a [virtual table]. This function returns a pointer to a string
10037** that is the name of the appropriate collation sequence to use for text
10038** comparisons on the constraint identified by its arguments.
10039**
10040** The first argument must be the pointer to the [sqlite3_index_info] object
10041** that is the first parameter to the xBestIndex() method. The second argument
10042** must be an index into the aConstraint[] array belonging to the
10043** sqlite3_index_info structure passed to xBestIndex.
10044**
10045** Important:
10046** The first parameter must be the same pointer that is passed into the
10047** xBestMethod() method. The first parameter may not be a pointer to a
10048** different [sqlite3_index_info] object, even an exact copy.
10049**
10050** The return value is computed as follows:
10051**
10052** <ol>
10053** <li><p> If the constraint comes from a WHERE clause expression that contains
10054** a [COLLATE operator], then the name of the collation specified by
10055** that COLLATE operator is returned.
10056** <li><p> If there is no COLLATE operator, but the column that is the subject
10057** of the constraint specifies an alternative collating sequence via
10058** a [COLLATE clause] on the column definition within the CREATE TABLE
10059** statement that was passed into [sqlite3_declare_vtab()], then the
10060** name of that alternative collating sequence is returned.
10061** <li><p> Otherwise, "BINARY" is returned.
10062** </ol>
10063*/
10064SQLITE_API const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
10065
10066/*
10067** CAPI3REF: Determine if a virtual table query is DISTINCT
10068** METHOD: sqlite3_index_info
10069**
10070** This API may only be used from within an [xBestIndex|xBestIndex method]
10071** of a [virtual table] implementation. The result of calling this
10072** interface from outside of xBestIndex() is undefined and probably harmful.
10073**
10074** ^The sqlite3_vtab_distinct() interface returns an integer between 0 and
10075** 3. The integer returned by sqlite3_vtab_distinct()
10076** gives the virtual table additional information about how the query
10077** planner wants the output to be ordered. As long as the virtual table
10078** can meet the ordering requirements of the query planner, it may set
10079** the "orderByConsumed" flag.
10080**
10081** <ol><li value="0"><p>
10082** ^If the sqlite3_vtab_distinct() interface returns 0, that means
10083** that the query planner needs the virtual table to return all rows in the
10084** sort order defined by the "nOrderBy" and "aOrderBy" fields of the
10085** [sqlite3_index_info] object. This is the default expectation. If the
10086** virtual table outputs all rows in sorted order, then it is always safe for
10087** the xBestIndex method to set the "orderByConsumed" flag, regardless of
10088** the return value from sqlite3_vtab_distinct().
10089** <li value="1"><p>
10090** ^(If the sqlite3_vtab_distinct() interface returns 1, that means
10091** that the query planner does not need the rows to be returned in sorted order
10092** as long as all rows with the same values in all columns identified by the
10093** "aOrderBy" field are adjacent.)^ This mode is used when the query planner
10094** is doing a GROUP BY.
10095** <li value="2"><p>
10096** ^(If the sqlite3_vtab_distinct() interface returns 2, that means
10097** that the query planner does not need the rows returned in any particular
10098** order, as long as rows with the same values in all columns identified
10099** by "aOrderBy" are adjacent.)^ ^(Furthermore, when two or more rows
10100** contain the same values for all columns identified by "colUsed", all but
10101** one such row may optionally be omitted from the result.)^
10102** The virtual table is not required to omit rows that are duplicates
10103** over the "colUsed" columns, but if the virtual table can do that without
10104** too much extra effort, it could potentially help the query to run faster.
10105** This mode is used for a DISTINCT query.
10106** <li value="3"><p>
10107** ^(If the sqlite3_vtab_distinct() interface returns 3, that means the
10108** virtual table must return rows in the order defined by "aOrderBy" as
10109** if the sqlite3_vtab_distinct() interface had returned 0. However if
10110** two or more rows in the result have the same values for all columns
10111** identified by "colUsed", then all but one such row may optionally be
10112** omitted.)^ Like when the return value is 2, the virtual table
10113** is not required to omit rows that are duplicates over the "colUsed"
10114** columns, but if the virtual table can do that without
10115** too much extra effort, it could potentially help the query to run faster.
10116** This mode is used for queries
10117** that have both DISTINCT and ORDER BY clauses.
10118** </ol>
10119**
10120** <p>The following table summarizes the conditions under which the
10121** virtual table is allowed to set the "orderByConsumed" flag based on
10122** the value returned by sqlite3_vtab_distinct(). This table is a
10123** restatement of the previous four paragraphs:
10124**
10125** <table border=1 cellspacing=0 cellpadding=10 width="90%">
10126** <tr>
10127** <td valign="top">sqlite3_vtab_distinct() return value
10128** <td valign="top">Rows are returned in aOrderBy order
10129** <td valign="top">Rows with the same value in all aOrderBy columns are adjacent
10130** <td valign="top">Duplicates over all colUsed columns may be omitted
10131** <tr><td>0<td>yes<td>yes<td>no
10132** <tr><td>1<td>no<td>yes<td>no
10133** <tr><td>2<td>no<td>yes<td>yes
10134** <tr><td>3<td>yes<td>yes<td>yes
10135** </table>
10136**
10137** ^For the purposes of comparing virtual table output values to see if the
10138** values are same value for sorting purposes, two NULL values are considered
10139** to be the same. In other words, the comparison operator is "IS"
10140** (or "IS NOT DISTINCT FROM") and not "==".
10141**
10142** If a virtual table implementation is unable to meet the requirements
10143** specified above, then it must not set the "orderByConsumed" flag in the
10144** [sqlite3_index_info] object or an incorrect answer may result.
10145**
10146** ^A virtual table implementation is always free to return rows in any order
10147** it wants, as long as the "orderByConsumed" flag is not set. ^When the
10148** the "orderByConsumed" flag is unset, the query planner will add extra
10149** [bytecode] to ensure that the final results returned by the SQL query are
10150** ordered correctly. The use of the "orderByConsumed" flag and the
10151** sqlite3_vtab_distinct() interface is merely an optimization. ^Careful
10152** use of the sqlite3_vtab_distinct() interface and the "orderByConsumed"
10153** flag might help queries against a virtual table to run faster. Being
10154** overly aggressive and setting the "orderByConsumed" flag when it is not
10155** valid to do so, on the other hand, might cause SQLite to return incorrect
10156** results.
10157*/
10158SQLITE_API int sqlite3_vtab_distinct(sqlite3_index_info*);
10159
10160/*
10161** CAPI3REF: Identify and handle IN constraints in xBestIndex
10162**
10163** This interface may only be used from within an
10164** [xBestIndex|xBestIndex() method] of a [virtual table] implementation.
10165** The result of invoking this interface from any other context is
10166** undefined and probably harmful.
10167**
10168** ^(A constraint on a virtual table of the form
10169** "[IN operator|column IN (...)]" is
10170** communicated to the xBestIndex method as a
10171** [SQLITE_INDEX_CONSTRAINT_EQ] constraint.)^ If xBestIndex wants to use
10172** this constraint, it must set the corresponding
10173** aConstraintUsage[].argvIndex to a positive integer. ^(Then, under
10174** the usual mode of handling IN operators, SQLite generates [bytecode]
10175** that invokes the [xFilter|xFilter() method] once for each value
10176** on the right-hand side of the IN operator.)^ Thus the virtual table
10177** only sees a single value from the right-hand side of the IN operator
10178** at a time.
10179**
10180** In some cases, however, it would be advantageous for the virtual
10181** table to see all values on the right-hand of the IN operator all at
10182** once. The sqlite3_vtab_in() interfaces facilitates this in two ways:
10183**
10184** <ol>
10185** <li><p>
10186** ^A call to sqlite3_vtab_in(P,N,-1) will return true (non-zero)
10187** if and only if the [sqlite3_index_info|P->aConstraint][N] constraint
10188** is an [IN operator] that can be processed all at once. ^In other words,
10189** sqlite3_vtab_in() with -1 in the third argument is a mechanism
10190** by which the virtual table can ask SQLite if all-at-once processing
10191** of the IN operator is even possible.
10192**
10193** <li><p>
10194** ^A call to sqlite3_vtab_in(P,N,F) with F==1 or F==0 indicates
10195** to SQLite that the virtual table does or does not want to process
10196** the IN operator all-at-once, respectively. ^Thus when the third
10197** parameter (F) is non-negative, this interface is the mechanism by
10198** which the virtual table tells SQLite how it wants to process the
10199** IN operator.
10200** </ol>
10201**
10202** ^The sqlite3_vtab_in(P,N,F) interface can be invoked multiple times
10203** within the same xBestIndex method call. ^For any given P,N pair,
10204** the return value from sqlite3_vtab_in(P,N,F) will always be the same
10205** within the same xBestIndex call. ^If the interface returns true
10206** (non-zero), that means that the constraint is an IN operator
10207** that can be processed all-at-once. ^If the constraint is not an IN
10208** operator or cannot be processed all-at-once, then the interface returns
10209** false.
10210**
10211** ^(All-at-once processing of the IN operator is selected if both of the
10212** following conditions are met:
10213**
10214** <ol>
10215** <li><p> The P->aConstraintUsage[N].argvIndex value is set to a positive
10216** integer. This is how the virtual table tells SQLite that it wants to
10217** use the N-th constraint.
10218**
10219** <li><p> The last call to sqlite3_vtab_in(P,N,F) for which F was
10220** non-negative had F>=1.
10221** </ol>)^
10222**
10223** ^If either or both of the conditions above are false, then SQLite uses
10224** the traditional one-at-a-time processing strategy for the IN constraint.
10225** ^If both conditions are true, then the argvIndex-th parameter to the
10226** xFilter method will be an [sqlite3_value] that appears to be NULL,
10227** but which can be passed to [sqlite3_vtab_in_first()] and
10228** [sqlite3_vtab_in_next()] to find all values on the right-hand side
10229** of the IN constraint.
10230*/
10231SQLITE_API int sqlite3_vtab_in(sqlite3_index_info*, int iCons, int bHandle);
10232
10233/*
10234** CAPI3REF: Find all elements on the right-hand side of an IN constraint.
10235**
10236** These interfaces are only useful from within the
10237** [xFilter|xFilter() method] of a [virtual table] implementation.
10238** The result of invoking these interfaces from any other context
10239** is undefined and probably harmful.
10240**
10241** The X parameter in a call to sqlite3_vtab_in_first(X,P) or
10242** sqlite3_vtab_in_next(X,P) should be one of the parameters to the
10243** xFilter method which invokes these routines, and specifically
10244** a parameter that was previously selected for all-at-once IN constraint
10245** processing use the [sqlite3_vtab_in()] interface in the
10246** [xBestIndex|xBestIndex method]. ^(If the X parameter is not
10247** an xFilter argument that was selected for all-at-once IN constraint
10248** processing, then these routines return [SQLITE_ERROR].)^
10249**
10250** ^(Use these routines to access all values on the right-hand side
10251** of the IN constraint using code like the following:
10252**
10253** <blockquote><pre>
10254** &nbsp; for(rc=sqlite3_vtab_in_first(pList, &pVal);
10255** &nbsp; rc==SQLITE_OK && pVal;
10256** &nbsp; rc=sqlite3_vtab_in_next(pList, &pVal)
10257** &nbsp; ){
10258** &nbsp; // do something with pVal
10259** &nbsp; }
10260** &nbsp; if( rc!=SQLITE_OK ){
10261** &nbsp; // an error has occurred
10262** &nbsp; }
10263** </pre></blockquote>)^
10264**
10265** ^On success, the sqlite3_vtab_in_first(X,P) and sqlite3_vtab_in_next(X,P)
10266** routines return SQLITE_OK and set *P to point to the first or next value
10267** on the RHS of the IN constraint. ^If there are no more values on the
10268** right hand side of the IN constraint, then *P is set to NULL and these
10269** routines return [SQLITE_DONE]. ^The return value might be
10270** some other value, such as SQLITE_NOMEM, in the event of a malfunction.
10271**
10272** The *ppOut values returned by these routines are only valid until the
10273** next call to either of these routines or until the end of the xFilter
10274** method from which these routines were called. If the virtual table
10275** implementation needs to retain the *ppOut values for longer, it must make
10276** copies. The *ppOut values are [protected sqlite3_value|protected].
10277*/
10278SQLITE_API int sqlite3_vtab_in_first(sqlite3_value *pVal, sqlite3_value **ppOut);
10279SQLITE_API int sqlite3_vtab_in_next(sqlite3_value *pVal, sqlite3_value **ppOut);
10280
10281/*
10282** CAPI3REF: Constraint values in xBestIndex()
10283** METHOD: sqlite3_index_info
10284**
10285** This API may only be used from within the [xBestIndex|xBestIndex method]
10286** of a [virtual table] implementation. The result of calling this interface
10287** from outside of an xBestIndex method are undefined and probably harmful.
10288**
10289** ^When the sqlite3_vtab_rhs_value(P,J,V) interface is invoked from within
10290** the [xBestIndex] method of a [virtual table] implementation, with P being
10291** a copy of the [sqlite3_index_info] object pointer passed into xBestIndex and
10292** J being a 0-based index into P->aConstraint[], then this routine
10293** attempts to set *V to the value of the right-hand operand of
10294** that constraint if the right-hand operand is known. ^If the
10295** right-hand operand is not known, then *V is set to a NULL pointer.
10296** ^The sqlite3_vtab_rhs_value(P,J,V) interface returns SQLITE_OK if
10297** and only if *V is set to a value. ^The sqlite3_vtab_rhs_value(P,J,V)
10298** inteface returns SQLITE_NOTFOUND if the right-hand side of the J-th
10299** constraint is not available. ^The sqlite3_vtab_rhs_value() interface
10300** can return an result code other than SQLITE_OK or SQLITE_NOTFOUND if
10301** something goes wrong.
10302**
10303** The sqlite3_vtab_rhs_value() interface is usually only successful if
10304** the right-hand operand of a constraint is a literal value in the original
10305** SQL statement. If the right-hand operand is an expression or a reference
10306** to some other column or a [host parameter], then sqlite3_vtab_rhs_value()
10307** will probably return [SQLITE_NOTFOUND].
10308**
10309** ^(Some constraints, such as [SQLITE_INDEX_CONSTRAINT_ISNULL] and
10310** [SQLITE_INDEX_CONSTRAINT_ISNOTNULL], have no right-hand operand. For such
10311** constraints, sqlite3_vtab_rhs_value() always returns SQLITE_NOTFOUND.)^
10312**
10313** ^The [sqlite3_value] object returned in *V is a protected sqlite3_value
10314** and remains valid for the duration of the xBestIndex method call.
10315** ^When xBestIndex returns, the sqlite3_value object returned by
10316** sqlite3_vtab_rhs_value() is automatically deallocated.
10317**
10318** The "_rhs_" in the name of this routine is an abbreviation for
10319** "Right-Hand Side".
10320*/
10321SQLITE_API int sqlite3_vtab_rhs_value(sqlite3_index_info*, int, sqlite3_value **ppVal);
10322
10323/*
10324** CAPI3REF: Conflict resolution modes
10325** KEYWORDS: {conflict resolution mode}
10326**
10327** These constants are returned by [sqlite3_vtab_on_conflict()] to
10328** inform a [virtual table] implementation what the [ON CONFLICT] mode
10329** is for the SQL statement being evaluated.
10330**
10331** Note that the [SQLITE_IGNORE] constant is also used as a potential
10332** return value from the [sqlite3_set_authorizer()] callback and that
10333** [SQLITE_ABORT] is also a [result code].
10334*/
10335#define SQLITE_ROLLBACK 1
10336/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
10337#define SQLITE_FAIL 3
10338/* #define SQLITE_ABORT 4 // Also an error code */
10339#define SQLITE_REPLACE 5
10340
10341/*
10342** CAPI3REF: Prepared Statement Scan Status Opcodes
10343** KEYWORDS: {scanstatus options}
10344**
10345** The following constants can be used for the T parameter to the
10346** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a
10347** different metric for sqlite3_stmt_scanstatus() to return.
10348**
10349** When the value returned to V is a string, space to hold that string is
10350** managed by the prepared statement S and will be automatically freed when
10351** S is finalized.
10352**
10353** Not all values are available for all query elements. When a value is
10354** not available, the output variable is set to -1 if the value is numeric,
10355** or to NULL if it is a string (SQLITE_SCANSTAT_NAME).
10356**
10357** <dl>
10358** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
10359** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be
10360** set to the total number of times that the X-th loop has run.</dd>
10361**
10362** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
10363** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set
10364** to the total number of rows examined by all iterations of the X-th loop.</dd>
10365**
10366** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
10367** <dd>^The "double" variable pointed to by the V parameter will be set to the
10368** query planner's estimate for the average number of rows output from each
10369** iteration of the X-th loop. If the query planner's estimates was accurate,
10370** then this value will approximate the quotient NVISIT/NLOOP and the
10371** product of this value for all prior loops with the same SELECTID will
10372** be the NLOOP value for the current loop.
10373**
10374** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
10375** <dd>^The "const char *" variable pointed to by the V parameter will be set
10376** to a zero-terminated UTF-8 string containing the name of the index or table
10377** used for the X-th loop.
10378**
10379** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
10380** <dd>^The "const char *" variable pointed to by the V parameter will be set
10381** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
10382** description for the X-th loop.
10383**
10384** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECTID</dt>
10385** <dd>^The "int" variable pointed to by the V parameter will be set to the
10386** id for the X-th query plan element. The id value is unique within the
10387** statement. The select-id is the same value as is output in the first
10388** column of an [EXPLAIN QUERY PLAN] query.
10389**
10390** [[SQLITE_SCANSTAT_PARENTID]] <dt>SQLITE_SCANSTAT_PARENTID</dt>
10391** <dd>The "int" variable pointed to by the V parameter will be set to the
10392** the id of the parent of the current query element, if applicable, or
10393** to zero if the query element has no parent. This is the same value as
10394** returned in the second column of an [EXPLAIN QUERY PLAN] query.
10395**
10396** [[SQLITE_SCANSTAT_NCYCLE]] <dt>SQLITE_SCANSTAT_NCYCLE</dt>
10397** <dd>The sqlite3_int64 output value is set to the number of cycles,
10398** according to the processor time-stamp counter, that elapsed while the
10399** query element was being processed. This value is not available for
10400** all query elements - if it is unavailable the output variable is
10401** set to -1.
10402** </dl>
10403*/
10404#define SQLITE_SCANSTAT_NLOOP 0
10405#define SQLITE_SCANSTAT_NVISIT 1
10406#define SQLITE_SCANSTAT_EST 2
10407#define SQLITE_SCANSTAT_NAME 3
10408#define SQLITE_SCANSTAT_EXPLAIN 4
10409#define SQLITE_SCANSTAT_SELECTID 5
10410#define SQLITE_SCANSTAT_PARENTID 6
10411#define SQLITE_SCANSTAT_NCYCLE 7
10412
10413/*
10414** CAPI3REF: Prepared Statement Scan Status
10415** METHOD: sqlite3_stmt
10416**
10417** These interfaces return information about the predicted and measured
10418** performance for pStmt. Advanced applications can use this
10419** interface to compare the predicted and the measured performance and
10420** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
10421**
10422** Since this interface is expected to be rarely used, it is only
10423** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
10424** compile-time option.
10425**
10426** The "iScanStatusOp" parameter determines which status information to return.
10427** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
10428** of this interface is undefined. ^The requested measurement is written into
10429** a variable pointed to by the "pOut" parameter.
10430**
10431** The "flags" parameter must be passed a mask of flags. At present only
10432** one flag is defined - SQLITE_SCANSTAT_COMPLEX. If SQLITE_SCANSTAT_COMPLEX
10433** is specified, then status information is available for all elements
10434** of a query plan that are reported by "EXPLAIN QUERY PLAN" output. If
10435** SQLITE_SCANSTAT_COMPLEX is not specified, then only query plan elements
10436** that correspond to query loops (the "SCAN..." and "SEARCH..." elements of
10437** the EXPLAIN QUERY PLAN output) are available. Invoking API
10438** sqlite3_stmt_scanstatus() is equivalent to calling
10439** sqlite3_stmt_scanstatus_v2() with a zeroed flags parameter.
10440**
10441** Parameter "idx" identifies the specific query element to retrieve statistics
10442** for. Query elements are numbered starting from zero. A value of -1 may be
10443** to query for statistics regarding the entire query. ^If idx is out of range
10444** - less than -1 or greater than or equal to the total number of query
10445** elements used to implement the statement - a non-zero value is returned and
10446** the variable that pOut points to is unchanged.
10447**
10448** See also: [sqlite3_stmt_scanstatus_reset()]
10449*/
10450SQLITE_API int sqlite3_stmt_scanstatus(
10451 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */
10452 int idx, /* Index of loop to report on */
10453 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */
10454 void *pOut /* Result written here */
10455);
10456SQLITE_API int sqlite3_stmt_scanstatus_v2(
10457 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */
10458 int idx, /* Index of loop to report on */
10459 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */
10460 int flags, /* Mask of flags defined below */
10461 void *pOut /* Result written here */
10462);
10463
10464/*
10465** CAPI3REF: Prepared Statement Scan Status
10466** KEYWORDS: {scan status flags}
10467*/
10468#define SQLITE_SCANSTAT_COMPLEX 0x0001
10469
10470/*
10471** CAPI3REF: Zero Scan-Status Counters
10472** METHOD: sqlite3_stmt
10473**
10474** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
10475**
10476** This API is only available if the library is built with pre-processor
10477** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
10478*/
10479SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
10480
10481/*
10482** CAPI3REF: Flush caches to disk mid-transaction
10483** METHOD: sqlite3
10484**
10485** ^If a write-transaction is open on [database connection] D when the
10486** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
10487** pages in the pager-cache that are not currently in use are written out
10488** to disk. A dirty page may be in use if a database cursor created by an
10489** active SQL statement is reading from it, or if it is page 1 of a database
10490** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)]
10491** interface flushes caches for all schemas - "main", "temp", and
10492** any [attached] databases.
10493**
10494** ^If this function needs to obtain extra database locks before dirty pages
10495** can be flushed to disk, it does so. ^If those locks cannot be obtained
10496** immediately and there is a busy-handler callback configured, it is invoked
10497** in the usual manner. ^If the required lock still cannot be obtained, then
10498** the database is skipped and an attempt made to flush any dirty pages
10499** belonging to the next (if any) database. ^If any databases are skipped
10500** because locks cannot be obtained, but no other error occurs, this
10501** function returns SQLITE_BUSY.
10502**
10503** ^If any other error occurs while flushing dirty pages to disk (for
10504** example an IO error or out-of-memory condition), then processing is
10505** abandoned and an SQLite [error code] is returned to the caller immediately.
10506**
10507** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
10508**
10509** ^This function does not set the database handle error code or message
10510** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
10511*/
10512SQLITE_API int sqlite3_db_cacheflush(sqlite3*);
10513
10514/*
10515** CAPI3REF: The pre-update hook.
10516** METHOD: sqlite3
10517**
10518** ^These interfaces are only available if SQLite is compiled using the
10519** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
10520**
10521** ^The [sqlite3_preupdate_hook()] interface registers a callback function
10522** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
10523** on a database table.
10524** ^At most one preupdate hook may be registered at a time on a single
10525** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
10526** the previous setting.
10527** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
10528** with a NULL pointer as the second parameter.
10529** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
10530** the first parameter to callbacks.
10531**
10532** ^The preupdate hook only fires for changes to real database tables; the
10533** preupdate hook is not invoked for changes to [virtual tables] or to
10534** system tables like sqlite_sequence or sqlite_stat1.
10535**
10536** ^The second parameter to the preupdate callback is a pointer to
10537** the [database connection] that registered the preupdate hook.
10538** ^The third parameter to the preupdate callback is one of the constants
10539** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
10540** kind of update operation that is about to occur.
10541** ^(The fourth parameter to the preupdate callback is the name of the
10542** database within the database connection that is being modified. This
10543** will be "main" for the main database or "temp" for TEMP tables or
10544** the name given after the AS keyword in the [ATTACH] statement for attached
10545** databases.)^
10546** ^The fifth parameter to the preupdate callback is the name of the
10547** table that is being modified.
10548**
10549** For an UPDATE or DELETE operation on a [rowid table], the sixth
10550** parameter passed to the preupdate callback is the initial [rowid] of the
10551** row being modified or deleted. For an INSERT operation on a rowid table,
10552** or any operation on a WITHOUT ROWID table, the value of the sixth
10553** parameter is undefined. For an INSERT or UPDATE on a rowid table the
10554** seventh parameter is the final rowid value of the row being inserted
10555** or updated. The value of the seventh parameter passed to the callback
10556** function is not defined for operations on WITHOUT ROWID tables, or for
10557** DELETE operations on rowid tables.
10558**
10559** ^The sqlite3_preupdate_hook(D,C,P) function returns the P argument from
10560** the previous call on the same [database connection] D, or NULL for
10561** the first call on D.
10562**
10563** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
10564** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
10565** provide additional information about a preupdate event. These routines
10566** may only be called from within a preupdate callback. Invoking any of
10567** these routines from outside of a preupdate callback or with a
10568** [database connection] pointer that is different from the one supplied
10569** to the preupdate callback results in undefined and probably undesirable
10570** behavior.
10571**
10572** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
10573** in the row that is being inserted, updated, or deleted.
10574**
10575** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
10576** a [protected sqlite3_value] that contains the value of the Nth column of
10577** the table row before it is updated. The N parameter must be between 0
10578** and one less than the number of columns or the behavior will be
10579** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
10580** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
10581** behavior is undefined. The [sqlite3_value] that P points to
10582** will be destroyed when the preupdate callback returns.
10583**
10584** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
10585** a [protected sqlite3_value] that contains the value of the Nth column of
10586** the table row after it is updated. The N parameter must be between 0
10587** and one less than the number of columns or the behavior will be
10588** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
10589** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
10590** behavior is undefined. The [sqlite3_value] that P points to
10591** will be destroyed when the preupdate callback returns.
10592**
10593** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
10594** callback was invoked as a result of a direct insert, update, or delete
10595** operation; or 1 for inserts, updates, or deletes invoked by top-level
10596** triggers; or 2 for changes resulting from triggers called by top-level
10597** triggers; and so forth.
10598**
10599** When the [sqlite3_blob_write()] API is used to update a blob column,
10600** the pre-update hook is invoked with SQLITE_DELETE. This is because the
10601** in this case the new values are not available. In this case, when a
10602** callback made with op==SQLITE_DELETE is actually a write using the
10603** sqlite3_blob_write() API, the [sqlite3_preupdate_blobwrite()] returns
10604** the index of the column being written. In other cases, where the
10605** pre-update hook is being invoked for some other reason, including a
10606** regular DELETE, sqlite3_preupdate_blobwrite() returns -1.
10607**
10608** See also: [sqlite3_update_hook()]
10609*/
10610#if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
10611SQLITE_API void *sqlite3_preupdate_hook(
10612 sqlite3 *db,
10613 void(*xPreUpdate)(
10614 void *pCtx, /* Copy of third arg to preupdate_hook() */
10615 sqlite3 *db, /* Database handle */
10616 int op, /* SQLITE_UPDATE, DELETE or INSERT */
10617 char const *zDb, /* Database name */
10618 char const *zName, /* Table name */
10619 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */
10620 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */
10621 ),
10622 void*
10623);
10624SQLITE_API int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
10625SQLITE_API int sqlite3_preupdate_count(sqlite3 *);
10626SQLITE_API int sqlite3_preupdate_depth(sqlite3 *);
10627SQLITE_API int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
10628SQLITE_API int sqlite3_preupdate_blobwrite(sqlite3 *);
10629#endif
10630
10631/*
10632** CAPI3REF: Low-level system error code
10633** METHOD: sqlite3
10634**
10635** ^Attempt to return the underlying operating system error code or error
10636** number that caused the most recent I/O error or failure to open a file.
10637** The return value is OS-dependent. For example, on unix systems, after
10638** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
10639** called to get back the underlying "errno" that caused the problem, such
10640** as ENOSPC, EAUTH, EISDIR, and so forth.
10641*/
10642SQLITE_API int sqlite3_system_errno(sqlite3*);
10643
10644/*
10645** CAPI3REF: Database Snapshot
10646** KEYWORDS: {snapshot} {sqlite3_snapshot}
10647**
10648** An instance of the snapshot object records the state of a [WAL mode]
10649** database for some specific point in history.
10650**
10651** In [WAL mode], multiple [database connections] that are open on the
10652** same database file can each be reading a different historical version
10653** of the database file. When a [database connection] begins a read
10654** transaction, that connection sees an unchanging copy of the database
10655** as it existed for the point in time when the transaction first started.
10656** Subsequent changes to the database from other connections are not seen
10657** by the reader until a new read transaction is started.
10658**
10659** The sqlite3_snapshot object records state information about an historical
10660** version of the database file so that it is possible to later open a new read
10661** transaction that sees that historical version of the database rather than
10662** the most recent version.
10663*/
10664typedef struct sqlite3_snapshot {
10665 unsigned char hidden[48];
10666} sqlite3_snapshot;
10667
10668/*
10669** CAPI3REF: Record A Database Snapshot
10670** CONSTRUCTOR: sqlite3_snapshot
10671**
10672** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
10673** new [sqlite3_snapshot] object that records the current state of
10674** schema S in database connection D. ^On success, the
10675** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
10676** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
10677** If there is not already a read-transaction open on schema S when
10678** this function is called, one is opened automatically.
10679**
10680** If a read-transaction is opened by this function, then it is guaranteed
10681** that the returned snapshot object may not be invalidated by a database
10682** writer or checkpointer until after the read-transaction is closed. This
10683** is not guaranteed if a read-transaction is already open when this
10684** function is called. In that case, any subsequent write or checkpoint
10685** operation on the database may invalidate the returned snapshot handle,
10686** even while the read-transaction remains open.
10687**
10688** The following must be true for this function to succeed. If any of
10689** the following statements are false when sqlite3_snapshot_get() is
10690** called, SQLITE_ERROR is returned. The final value of *P is undefined
10691** in this case.
10692**
10693** <ul>
10694** <li> The database handle must not be in [autocommit mode].
10695**
10696** <li> Schema S of [database connection] D must be a [WAL mode] database.
10697**
10698** <li> There must not be a write transaction open on schema S of database
10699** connection D.
10700**
10701** <li> One or more transactions must have been written to the current wal
10702** file since it was created on disk (by any connection). This means
10703** that a snapshot cannot be taken on a wal mode database with no wal
10704** file immediately after it is first opened. At least one transaction
10705** must be written to it first.
10706** </ul>
10707**
10708** This function may also return SQLITE_NOMEM. If it is called with the
10709** database handle in autocommit mode but fails for some other reason,
10710** whether or not a read transaction is opened on schema S is undefined.
10711**
10712** The [sqlite3_snapshot] object returned from a successful call to
10713** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
10714** to avoid a memory leak.
10715**
10716** The [sqlite3_snapshot_get()] interface is only available when the
10717** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
10718*/
10719SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
10720 sqlite3 *db,
10721 const char *zSchema,
10722 sqlite3_snapshot **ppSnapshot
10723);
10724
10725/*
10726** CAPI3REF: Start a read transaction on an historical snapshot
10727** METHOD: sqlite3_snapshot
10728**
10729** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read
10730** transaction or upgrades an existing one for schema S of
10731** [database connection] D such that the read transaction refers to
10732** historical [snapshot] P, rather than the most recent change to the
10733** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK
10734** on success or an appropriate [error code] if it fails.
10735**
10736** ^In order to succeed, the database connection must not be in
10737** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there
10738** is already a read transaction open on schema S, then the database handle
10739** must have no active statements (SELECT statements that have been passed
10740** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()).
10741** SQLITE_ERROR is returned if either of these conditions is violated, or
10742** if schema S does not exist, or if the snapshot object is invalid.
10743**
10744** ^A call to sqlite3_snapshot_open() will fail to open if the specified
10745** snapshot has been overwritten by a [checkpoint]. In this case
10746** SQLITE_ERROR_SNAPSHOT is returned.
10747**
10748** If there is already a read transaction open when this function is
10749** invoked, then the same read transaction remains open (on the same
10750** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT
10751** is returned. If another error code - for example SQLITE_PROTOCOL or an
10752** SQLITE_IOERR error code - is returned, then the final state of the
10753** read transaction is undefined. If SQLITE_OK is returned, then the
10754** read transaction is now open on database snapshot P.
10755**
10756** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
10757** database connection D does not know that the database file for
10758** schema S is in [WAL mode]. A database connection might not know
10759** that the database file is in [WAL mode] if there has been no prior
10760** I/O on that database connection, or if the database entered [WAL mode]
10761** after the most recent I/O on the database connection.)^
10762** (Hint: Run "[PRAGMA application_id]" against a newly opened
10763** database connection in order to make it ready to use snapshots.)
10764**
10765** The [sqlite3_snapshot_open()] interface is only available when the
10766** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
10767*/
10768SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
10769 sqlite3 *db,
10770 const char *zSchema,
10771 sqlite3_snapshot *pSnapshot
10772);
10773
10774/*
10775** CAPI3REF: Destroy a snapshot
10776** DESTRUCTOR: sqlite3_snapshot
10777**
10778** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
10779** The application must eventually free every [sqlite3_snapshot] object
10780** using this routine to avoid a memory leak.
10781**
10782** The [sqlite3_snapshot_free()] interface is only available when the
10783** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
10784*/
10785SQLITE_API SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);
10786
10787/*
10788** CAPI3REF: Compare the ages of two snapshot handles.
10789** METHOD: sqlite3_snapshot
10790**
10791** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
10792** of two valid snapshot handles.
10793**
10794** If the two snapshot handles are not associated with the same database
10795** file, the result of the comparison is undefined.
10796**
10797** Additionally, the result of the comparison is only valid if both of the
10798** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
10799** last time the wal file was deleted. The wal file is deleted when the
10800** database is changed back to rollback mode or when the number of database
10801** clients drops to zero. If either snapshot handle was obtained before the
10802** wal file was last deleted, the value returned by this function
10803** is undefined.
10804**
10805** Otherwise, this API returns a negative value if P1 refers to an older
10806** snapshot than P2, zero if the two handles refer to the same database
10807** snapshot, and a positive value if P1 is a newer snapshot than P2.
10808**
10809** This interface is only available if SQLite is compiled with the
10810** [SQLITE_ENABLE_SNAPSHOT] option.
10811*/
10812SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp(
10813 sqlite3_snapshot *p1,
10814 sqlite3_snapshot *p2
10815);
10816
10817/*
10818** CAPI3REF: Recover snapshots from a wal file
10819** METHOD: sqlite3_snapshot
10820**
10821** If a [WAL file] remains on disk after all database connections close
10822** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control]
10823** or because the last process to have the database opened exited without
10824** calling [sqlite3_close()]) and a new connection is subsequently opened
10825** on that database and [WAL file], the [sqlite3_snapshot_open()] interface
10826** will only be able to open the last transaction added to the WAL file
10827** even though the WAL file contains other valid transactions.
10828**
10829** This function attempts to scan the WAL file associated with database zDb
10830** of database handle db and make all valid snapshots available to
10831** sqlite3_snapshot_open(). It is an error if there is already a read
10832** transaction open on the database, or if the database is not a WAL mode
10833** database.
10834**
10835** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
10836**
10837** This interface is only available if SQLite is compiled with the
10838** [SQLITE_ENABLE_SNAPSHOT] option.
10839*/
10840SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
10841
10842/*
10843** CAPI3REF: Serialize a database
10844**
10845** The sqlite3_serialize(D,S,P,F) interface returns a pointer to
10846** memory that is a serialization of the S database on
10847** [database connection] D. If S is a NULL pointer, the main database is used.
10848** If P is not a NULL pointer, then the size of the database in bytes
10849** is written into *P.
10850**
10851** For an ordinary on-disk database file, the serialization is just a
10852** copy of the disk file. For an in-memory database or a "TEMP" database,
10853** the serialization is the same sequence of bytes which would be written
10854** to disk if that database where backed up to disk.
10855**
10856** The usual case is that sqlite3_serialize() copies the serialization of
10857** the database into memory obtained from [sqlite3_malloc64()] and returns
10858** a pointer to that memory. The caller is responsible for freeing the
10859** returned value to avoid a memory leak. However, if the F argument
10860** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations
10861** are made, and the sqlite3_serialize() function will return a pointer
10862** to the contiguous memory representation of the database that SQLite
10863** is currently using for that database, or NULL if the no such contiguous
10864** memory representation of the database exists. A contiguous memory
10865** representation of the database will usually only exist if there has
10866** been a prior call to [sqlite3_deserialize(D,S,...)] with the same
10867** values of D and S.
10868** The size of the database is written into *P even if the
10869** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy
10870** of the database exists.
10871**
10872** After the call, if the SQLITE_SERIALIZE_NOCOPY bit had been set,
10873** the returned buffer content will remain accessible and unchanged
10874** until either the next write operation on the connection or when
10875** the connection is closed, and applications must not modify the
10876** buffer. If the bit had been clear, the returned buffer will not
10877** be accessed by SQLite after the call.
10878**
10879** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the
10880** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory
10881** allocation error occurs.
10882**
10883** This interface is omitted if SQLite is compiled with the
10884** [SQLITE_OMIT_DESERIALIZE] option.
10885*/
10886SQLITE_API unsigned char *sqlite3_serialize(
10887 sqlite3 *db, /* The database connection */
10888 const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */
10889 sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */
10890 unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */
10891);
10892
10893/*
10894** CAPI3REF: Flags for sqlite3_serialize
10895**
10896** Zero or more of the following constants can be OR-ed together for
10897** the F argument to [sqlite3_serialize(D,S,P,F)].
10898**
10899** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return
10900** a pointer to contiguous in-memory database that it is currently using,
10901** without making a copy of the database. If SQLite is not currently using
10902** a contiguous in-memory database, then this option causes
10903** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be
10904** using a contiguous in-memory database if it has been initialized by a
10905** prior call to [sqlite3_deserialize()].
10906*/
10907#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */
10908
10909/*
10910** CAPI3REF: Deserialize a database
10911**
10912** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the
10913** [database connection] D to disconnect from database S and then
10914** reopen S as an in-memory database based on the serialization contained
10915** in P. The serialized database P is N bytes in size. M is the size of
10916** the buffer P, which might be larger than N. If M is larger than N, and
10917** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is
10918** permitted to add content to the in-memory database as long as the total
10919** size does not exceed M bytes.
10920**
10921** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will
10922** invoke sqlite3_free() on the serialization buffer when the database
10923** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then
10924** SQLite will try to increase the buffer size using sqlite3_realloc64()
10925** if writes on the database cause it to grow larger than M bytes.
10926**
10927** Applications must not modify the buffer P or invalidate it before
10928** the database connection D is closed.
10929**
10930** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the
10931** database is currently in a read transaction or is involved in a backup
10932** operation.
10933**
10934** It is not possible to deserialized into the TEMP database. If the
10935** S argument to sqlite3_deserialize(D,S,P,N,M,F) is "temp" then the
10936** function returns SQLITE_ERROR.
10937**
10938** The deserialized database should not be in [WAL mode]. If the database
10939** is in WAL mode, then any attempt to use the database file will result
10940** in an [SQLITE_CANTOPEN] error. The application can set the
10941** [file format version numbers] (bytes 18 and 19) of the input database P
10942** to 0x01 prior to invoking sqlite3_deserialize(D,S,P,N,M,F) to force the
10943** database file into rollback mode and work around this limitation.
10944**
10945** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the
10946** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then
10947** [sqlite3_free()] is invoked on argument P prior to returning.
10948**
10949** This interface is omitted if SQLite is compiled with the
10950** [SQLITE_OMIT_DESERIALIZE] option.
10951*/
10952SQLITE_API int sqlite3_deserialize(
10953 sqlite3 *db, /* The database connection */
10954 const char *zSchema, /* Which DB to reopen with the deserialization */
10955 unsigned char *pData, /* The serialized database content */
10956 sqlite3_int64 szDb, /* Number bytes in the deserialization */
10957 sqlite3_int64 szBuf, /* Total size of buffer pData[] */
10958 unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */
10959);
10960
10961/*
10962** CAPI3REF: Flags for sqlite3_deserialize()
10963**
10964** The following are allowed values for 6th argument (the F argument) to
10965** the [sqlite3_deserialize(D,S,P,N,M,F)] interface.
10966**
10967** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization
10968** in the P argument is held in memory obtained from [sqlite3_malloc64()]
10969** and that SQLite should take ownership of this memory and automatically
10970** free it when it has finished using it. Without this flag, the caller
10971** is responsible for freeing any dynamically allocated memory.
10972**
10973** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to
10974** grow the size of the database using calls to [sqlite3_realloc64()]. This
10975** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used.
10976** Without this flag, the deserialized database cannot increase in size beyond
10977** the number of bytes specified by the M parameter.
10978**
10979** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database
10980** should be treated as read-only.
10981*/
10982#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */
10983#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */
10984#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */
10985
10986/*
10987** Undo the hack that converts floating point types to integer for
10988** builds on processors without floating point support.
10989*/
10990#ifdef SQLITE_OMIT_FLOATING_POINT
10991# undef double
10992#endif
10993
10994#if defined(__wasi__)
10995# undef SQLITE_WASI
10996# define SQLITE_WASI 1
10997# ifndef SQLITE_OMIT_LOAD_EXTENSION
10998# define SQLITE_OMIT_LOAD_EXTENSION
10999# endif
11000# ifndef SQLITE_THREADSAFE
11001# define SQLITE_THREADSAFE 0
11002# endif
11003#endif
11004
11005#ifdef __cplusplus
11006} /* End of the 'extern "C"' block */
11007#endif
11008/* #endif for SQLITE3_H will be added by mksqlite3.tcl */
11009
11010/******** Begin file sqlite3rtree.h *********/
11011/*
11012** 2010 August 30
11013**
11014** The author disclaims copyright to this source code. In place of
11015** a legal notice, here is a blessing:
11016**
11017** May you do good and not evil.
11018** May you find forgiveness for yourself and forgive others.
11019** May you share freely, never taking more than you give.
11020**
11021*************************************************************************
11022*/
11023
11024#ifndef _SQLITE3RTREE_H_
11025#define _SQLITE3RTREE_H_
11026
11027
11028#ifdef __cplusplus
11029extern "C" {
11030#endif
11031
11032typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
11033typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
11034
11035/* The double-precision datatype used by RTree depends on the
11036** SQLITE_RTREE_INT_ONLY compile-time option.
11037*/
11038#ifdef SQLITE_RTREE_INT_ONLY
11039 typedef sqlite3_int64 sqlite3_rtree_dbl;
11040#else
11041 typedef double sqlite3_rtree_dbl;
11042#endif
11043
11044/*
11045** Register a geometry callback named zGeom that can be used as part of an
11046** R-Tree geometry query as follows:
11047**
11048** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
11049*/
11050SQLITE_API int sqlite3_rtree_geometry_callback(
11051 sqlite3 *db,
11052 const char *zGeom,
11053 int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
11054 void *pContext
11055);
11056
11057
11058/*
11059** A pointer to a structure of the following type is passed as the first
11060** argument to callbacks registered using rtree_geometry_callback().
11061*/
11062struct sqlite3_rtree_geometry {
11063 void *pContext; /* Copy of pContext passed to s_r_g_c() */
11064 int nParam; /* Size of array aParam[] */
11065 sqlite3_rtree_dbl *aParam; /* Parameters passed to SQL geom function */
11066 void *pUser; /* Callback implementation user data */
11067 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */
11068};
11069
11070/*
11071** Register a 2nd-generation geometry callback named zScore that can be
11072** used as part of an R-Tree geometry query as follows:
11073**
11074** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
11075*/
11076SQLITE_API int sqlite3_rtree_query_callback(
11077 sqlite3 *db,
11078 const char *zQueryFunc,
11079 int (*xQueryFunc)(sqlite3_rtree_query_info*),
11080 void *pContext,
11081 void (*xDestructor)(void*)
11082);
11083
11084
11085/*
11086** A pointer to a structure of the following type is passed as the
11087** argument to scored geometry callback registered using
11088** sqlite3_rtree_query_callback().
11089**
11090** Note that the first 5 fields of this structure are identical to
11091** sqlite3_rtree_geometry. This structure is a subclass of
11092** sqlite3_rtree_geometry.
11093*/
11094struct sqlite3_rtree_query_info {
11095 void *pContext; /* pContext from when function registered */
11096 int nParam; /* Number of function parameters */
11097 sqlite3_rtree_dbl *aParam; /* value of function parameters */
11098 void *pUser; /* callback can use this, if desired */
11099 void (*xDelUser)(void*); /* function to free pUser */
11100 sqlite3_rtree_dbl *aCoord; /* Coordinates of node or entry to check */
11101 unsigned int *anQueue; /* Number of pending entries in the queue */
11102 int nCoord; /* Number of coordinates */
11103 int iLevel; /* Level of current node or entry */
11104 int mxLevel; /* The largest iLevel value in the tree */
11105 sqlite3_int64 iRowid; /* Rowid for current entry */
11106 sqlite3_rtree_dbl rParentScore; /* Score of parent node */
11107 int eParentWithin; /* Visibility of parent node */
11108 int eWithin; /* OUT: Visibility */
11109 sqlite3_rtree_dbl rScore; /* OUT: Write the score here */
11110 /* The following fields are only available in 3.8.11 and later */
11111 sqlite3_value **apSqlParam; /* Original SQL values of parameters */
11112};
11113
11114/*
11115** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
11116*/
11117#define NOT_WITHIN 0 /* Object completely outside of query region */
11118#define PARTLY_WITHIN 1 /* Object partially overlaps query region */
11119#define FULLY_WITHIN 2 /* Object fully contained within query region */
11120
11121
11122#ifdef __cplusplus
11123} /* end of the 'extern "C"' block */
11124#endif
11125
11126#endif /* ifndef _SQLITE3RTREE_H_ */
11127
11128/******** End of sqlite3rtree.h *********/
11129/******** Begin file sqlite3session.h *********/
11130
11131#if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION)
11132#define __SQLITESESSION_H_ 1
11133
11134/*
11135** Make sure we can call this stuff from C++.
11136*/
11137#ifdef __cplusplus
11138extern "C" {
11139#endif
11140
11141
11142/*
11143** CAPI3REF: Session Object Handle
11144**
11145** An instance of this object is a [session] that can be used to
11146** record changes to a database.
11147*/
11148typedef struct sqlite3_session sqlite3_session;
11149
11150/*
11151** CAPI3REF: Changeset Iterator Handle
11152**
11153** An instance of this object acts as a cursor for iterating
11154** over the elements of a [changeset] or [patchset].
11155*/
11156typedef struct sqlite3_changeset_iter sqlite3_changeset_iter;
11157
11158/*
11159** CAPI3REF: Create A New Session Object
11160** CONSTRUCTOR: sqlite3_session
11161**
11162** Create a new session object attached to database handle db. If successful,
11163** a pointer to the new object is written to *ppSession and SQLITE_OK is
11164** returned. If an error occurs, *ppSession is set to NULL and an SQLite
11165** error code (e.g. SQLITE_NOMEM) is returned.
11166**
11167** It is possible to create multiple session objects attached to a single
11168** database handle.
11169**
11170** Session objects created using this function should be deleted using the
11171** [sqlite3session_delete()] function before the database handle that they
11172** are attached to is itself closed. If the database handle is closed before
11173** the session object is deleted, then the results of calling any session
11174** module function, including [sqlite3session_delete()] on the session object
11175** are undefined.
11176**
11177** Because the session module uses the [sqlite3_preupdate_hook()] API, it
11178** is not possible for an application to register a pre-update hook on a
11179** database handle that has one or more session objects attached. Nor is
11180** it possible to create a session object attached to a database handle for
11181** which a pre-update hook is already defined. The results of attempting
11182** either of these things are undefined.
11183**
11184** The session object will be used to create changesets for tables in
11185** database zDb, where zDb is either "main", or "temp", or the name of an
11186** attached database. It is not an error if database zDb is not attached
11187** to the database when the session object is created.
11188*/
11189SQLITE_API int sqlite3session_create(
11190 sqlite3 *db, /* Database handle */
11191 const char *zDb, /* Name of db (e.g. "main") */
11192 sqlite3_session **ppSession /* OUT: New session object */
11193);
11194
11195/*
11196** CAPI3REF: Delete A Session Object
11197** DESTRUCTOR: sqlite3_session
11198**
11199** Delete a session object previously allocated using
11200** [sqlite3session_create()]. Once a session object has been deleted, the
11201** results of attempting to use pSession with any other session module
11202** function are undefined.
11203**
11204** Session objects must be deleted before the database handle to which they
11205** are attached is closed. Refer to the documentation for
11206** [sqlite3session_create()] for details.
11207*/
11208SQLITE_API void sqlite3session_delete(sqlite3_session *pSession);
11209
11210/*
11211** CAPI3REF: Configure a Session Object
11212** METHOD: sqlite3_session
11213**
11214** This method is used to configure a session object after it has been
11215** created. At present the only valid values for the second parameter are
11216** [SQLITE_SESSION_OBJCONFIG_SIZE] and [SQLITE_SESSION_OBJCONFIG_ROWID].
11217**
11218*/
11219SQLITE_API int sqlite3session_object_config(sqlite3_session*, int op, void *pArg);
11220
11221/*
11222** CAPI3REF: Options for sqlite3session_object_config
11223**
11224** The following values may passed as the the 2nd parameter to
11225** sqlite3session_object_config().
11226**
11227** <dt>SQLITE_SESSION_OBJCONFIG_SIZE <dd>
11228** This option is used to set, clear or query the flag that enables
11229** the [sqlite3session_changeset_size()] API. Because it imposes some
11230** computational overhead, this API is disabled by default. Argument
11231** pArg must point to a value of type (int). If the value is initially
11232** 0, then the sqlite3session_changeset_size() API is disabled. If it
11233** is greater than 0, then the same API is enabled. Or, if the initial
11234** value is less than zero, no change is made. In all cases the (int)
11235** variable is set to 1 if the sqlite3session_changeset_size() API is
11236** enabled following the current call, or 0 otherwise.
11237**
11238** It is an error (SQLITE_MISUSE) to attempt to modify this setting after
11239** the first table has been attached to the session object.
11240**
11241** <dt>SQLITE_SESSION_OBJCONFIG_ROWID <dd>
11242** This option is used to set, clear or query the flag that enables
11243** collection of data for tables with no explicit PRIMARY KEY.
11244**
11245** Normally, tables with no explicit PRIMARY KEY are simply ignored
11246** by the sessions module. However, if this flag is set, it behaves
11247** as if such tables have a column "_rowid_ INTEGER PRIMARY KEY" inserted
11248** as their leftmost columns.
11249**
11250** It is an error (SQLITE_MISUSE) to attempt to modify this setting after
11251** the first table has been attached to the session object.
11252*/
11253#define SQLITE_SESSION_OBJCONFIG_SIZE 1
11254#define SQLITE_SESSION_OBJCONFIG_ROWID 2
11255
11256/*
11257** CAPI3REF: Enable Or Disable A Session Object
11258** METHOD: sqlite3_session
11259**
11260** Enable or disable the recording of changes by a session object. When
11261** enabled, a session object records changes made to the database. When
11262** disabled - it does not. A newly created session object is enabled.
11263** Refer to the documentation for [sqlite3session_changeset()] for further
11264** details regarding how enabling and disabling a session object affects
11265** the eventual changesets.
11266**
11267** Passing zero to this function disables the session. Passing a value
11268** greater than zero enables it. Passing a value less than zero is a
11269** no-op, and may be used to query the current state of the session.
11270**
11271** The return value indicates the final state of the session object: 0 if
11272** the session is disabled, or 1 if it is enabled.
11273*/
11274SQLITE_API int sqlite3session_enable(sqlite3_session *pSession, int bEnable);
11275
11276/*
11277** CAPI3REF: Set Or Clear the Indirect Change Flag
11278** METHOD: sqlite3_session
11279**
11280** Each change recorded by a session object is marked as either direct or
11281** indirect. A change is marked as indirect if either:
11282**
11283** <ul>
11284** <li> The session object "indirect" flag is set when the change is
11285** made, or
11286** <li> The change is made by an SQL trigger or foreign key action
11287** instead of directly as a result of a users SQL statement.
11288** </ul>
11289**
11290** If a single row is affected by more than one operation within a session,
11291** then the change is considered indirect if all operations meet the criteria
11292** for an indirect change above, or direct otherwise.
11293**
11294** This function is used to set, clear or query the session object indirect
11295** flag. If the second argument passed to this function is zero, then the
11296** indirect flag is cleared. If it is greater than zero, the indirect flag
11297** is set. Passing a value less than zero does not modify the current value
11298** of the indirect flag, and may be used to query the current state of the
11299** indirect flag for the specified session object.
11300**
11301** The return value indicates the final state of the indirect flag: 0 if
11302** it is clear, or 1 if it is set.
11303*/
11304SQLITE_API int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect);
11305
11306/*
11307** CAPI3REF: Attach A Table To A Session Object
11308** METHOD: sqlite3_session
11309**
11310** If argument zTab is not NULL, then it is the name of a table to attach
11311** to the session object passed as the first argument. All subsequent changes
11312** made to the table while the session object is enabled will be recorded. See
11313** documentation for [sqlite3session_changeset()] for further details.
11314**
11315** Or, if argument zTab is NULL, then changes are recorded for all tables
11316** in the database. If additional tables are added to the database (by
11317** executing "CREATE TABLE" statements) after this call is made, changes for
11318** the new tables are also recorded.
11319**
11320** Changes can only be recorded for tables that have a PRIMARY KEY explicitly
11321** defined as part of their CREATE TABLE statement. It does not matter if the
11322** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY
11323** KEY may consist of a single column, or may be a composite key.
11324**
11325** It is not an error if the named table does not exist in the database. Nor
11326** is it an error if the named table does not have a PRIMARY KEY. However,
11327** no changes will be recorded in either of these scenarios.
11328**
11329** Changes are not recorded for individual rows that have NULL values stored
11330** in one or more of their PRIMARY KEY columns.
11331**
11332** SQLITE_OK is returned if the call completes without error. Or, if an error
11333** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
11334**
11335** <h3>Special sqlite_stat1 Handling</h3>
11336**
11337** As of SQLite version 3.22.0, the "sqlite_stat1" table is an exception to
11338** some of the rules above. In SQLite, the schema of sqlite_stat1 is:
11339** <pre>
11340** &nbsp; CREATE TABLE sqlite_stat1(tbl,idx,stat)
11341** </pre>
11342**
11343** Even though sqlite_stat1 does not have a PRIMARY KEY, changes are
11344** recorded for it as if the PRIMARY KEY is (tbl,idx). Additionally, changes
11345** are recorded for rows for which (idx IS NULL) is true. However, for such
11346** rows a zero-length blob (SQL value X'') is stored in the changeset or
11347** patchset instead of a NULL value. This allows such changesets to be
11348** manipulated by legacy implementations of sqlite3changeset_invert(),
11349** concat() and similar.
11350**
11351** The sqlite3changeset_apply() function automatically converts the
11352** zero-length blob back to a NULL value when updating the sqlite_stat1
11353** table. However, if the application calls sqlite3changeset_new(),
11354** sqlite3changeset_old() or sqlite3changeset_conflict on a changeset
11355** iterator directly (including on a changeset iterator passed to a
11356** conflict-handler callback) then the X'' value is returned. The application
11357** must translate X'' to NULL itself if required.
11358**
11359** Legacy (older than 3.22.0) versions of the sessions module cannot capture
11360** changes made to the sqlite_stat1 table. Legacy versions of the
11361** sqlite3changeset_apply() function silently ignore any modifications to the
11362** sqlite_stat1 table that are part of a changeset or patchset.
11363*/
11364SQLITE_API int sqlite3session_attach(
11365 sqlite3_session *pSession, /* Session object */
11366 const char *zTab /* Table name */
11367);
11368
11369/*
11370** CAPI3REF: Set a table filter on a Session Object.
11371** METHOD: sqlite3_session
11372**
11373** The second argument (xFilter) is the "filter callback". For changes to rows
11374** in tables that are not attached to the Session object, the filter is called
11375** to determine whether changes to the table's rows should be tracked or not.
11376** If xFilter returns 0, changes are not tracked. Note that once a table is
11377** attached, xFilter will not be called again.
11378*/
11379SQLITE_API void sqlite3session_table_filter(
11380 sqlite3_session *pSession, /* Session object */
11381 int(*xFilter)(
11382 void *pCtx, /* Copy of third arg to _filter_table() */
11383 const char *zTab /* Table name */
11384 ),
11385 void *pCtx /* First argument passed to xFilter */
11386);
11387
11388/*
11389** CAPI3REF: Generate A Changeset From A Session Object
11390** METHOD: sqlite3_session
11391**
11392** Obtain a changeset containing changes to the tables attached to the
11393** session object passed as the first argument. If successful,
11394** set *ppChangeset to point to a buffer containing the changeset
11395** and *pnChangeset to the size of the changeset in bytes before returning
11396** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to
11397** zero and return an SQLite error code.
11398**
11399** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes,
11400** each representing a change to a single row of an attached table. An INSERT
11401** change contains the values of each field of a new database row. A DELETE
11402** contains the original values of each field of a deleted database row. An
11403** UPDATE change contains the original values of each field of an updated
11404** database row along with the updated values for each updated non-primary-key
11405** column. It is not possible for an UPDATE change to represent a change that
11406** modifies the values of primary key columns. If such a change is made, it
11407** is represented in a changeset as a DELETE followed by an INSERT.
11408**
11409** Changes are not recorded for rows that have NULL values stored in one or
11410** more of their PRIMARY KEY columns. If such a row is inserted or deleted,
11411** no corresponding change is present in the changesets returned by this
11412** function. If an existing row with one or more NULL values stored in
11413** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL,
11414** only an INSERT is appears in the changeset. Similarly, if an existing row
11415** with non-NULL PRIMARY KEY values is updated so that one or more of its
11416** PRIMARY KEY columns are set to NULL, the resulting changeset contains a
11417** DELETE change only.
11418**
11419** The contents of a changeset may be traversed using an iterator created
11420** using the [sqlite3changeset_start()] API. A changeset may be applied to
11421** a database with a compatible schema using the [sqlite3changeset_apply()]
11422** API.
11423**
11424** Within a changeset generated by this function, all changes related to a
11425** single table are grouped together. In other words, when iterating through
11426** a changeset or when applying a changeset to a database, all changes related
11427** to a single table are processed before moving on to the next table. Tables
11428** are sorted in the same order in which they were attached (or auto-attached)
11429** to the sqlite3_session object. The order in which the changes related to
11430** a single table are stored is undefined.
11431**
11432** Following a successful call to this function, it is the responsibility of
11433** the caller to eventually free the buffer that *ppChangeset points to using
11434** [sqlite3_free()].
11435**
11436** <h3>Changeset Generation</h3>
11437**
11438** Once a table has been attached to a session object, the session object
11439** records the primary key values of all new rows inserted into the table.
11440** It also records the original primary key and other column values of any
11441** deleted or updated rows. For each unique primary key value, data is only
11442** recorded once - the first time a row with said primary key is inserted,
11443** updated or deleted in the lifetime of the session.
11444**
11445** There is one exception to the previous paragraph: when a row is inserted,
11446** updated or deleted, if one or more of its primary key columns contain a
11447** NULL value, no record of the change is made.
11448**
11449** The session object therefore accumulates two types of records - those
11450** that consist of primary key values only (created when the user inserts
11451** a new record) and those that consist of the primary key values and the
11452** original values of other table columns (created when the users deletes
11453** or updates a record).
11454**
11455** When this function is called, the requested changeset is created using
11456** both the accumulated records and the current contents of the database
11457** file. Specifically:
11458**
11459** <ul>
11460** <li> For each record generated by an insert, the database is queried
11461** for a row with a matching primary key. If one is found, an INSERT
11462** change is added to the changeset. If no such row is found, no change
11463** is added to the changeset.
11464**
11465** <li> For each record generated by an update or delete, the database is
11466** queried for a row with a matching primary key. If such a row is
11467** found and one or more of the non-primary key fields have been
11468** modified from their original values, an UPDATE change is added to
11469** the changeset. Or, if no such row is found in the table, a DELETE
11470** change is added to the changeset. If there is a row with a matching
11471** primary key in the database, but all fields contain their original
11472** values, no change is added to the changeset.
11473** </ul>
11474**
11475** This means, amongst other things, that if a row is inserted and then later
11476** deleted while a session object is active, neither the insert nor the delete
11477** will be present in the changeset. Or if a row is deleted and then later a
11478** row with the same primary key values inserted while a session object is
11479** active, the resulting changeset will contain an UPDATE change instead of
11480** a DELETE and an INSERT.
11481**
11482** When a session object is disabled (see the [sqlite3session_enable()] API),
11483** it does not accumulate records when rows are inserted, updated or deleted.
11484** This may appear to have some counter-intuitive effects if a single row
11485** is written to more than once during a session. For example, if a row
11486** is inserted while a session object is enabled, then later deleted while
11487** the same session object is disabled, no INSERT record will appear in the
11488** changeset, even though the delete took place while the session was disabled.
11489** Or, if one field of a row is updated while a session is disabled, and
11490** another field of the same row is updated while the session is enabled, the
11491** resulting changeset will contain an UPDATE change that updates both fields.
11492*/
11493SQLITE_API int sqlite3session_changeset(
11494 sqlite3_session *pSession, /* Session object */
11495 int *pnChangeset, /* OUT: Size of buffer at *ppChangeset */
11496 void **ppChangeset /* OUT: Buffer containing changeset */
11497);
11498
11499/*
11500** CAPI3REF: Return An Upper-limit For The Size Of The Changeset
11501** METHOD: sqlite3_session
11502**
11503** By default, this function always returns 0. For it to return
11504** a useful result, the sqlite3_session object must have been configured
11505** to enable this API using sqlite3session_object_config() with the
11506** SQLITE_SESSION_OBJCONFIG_SIZE verb.
11507**
11508** When enabled, this function returns an upper limit, in bytes, for the size
11509** of the changeset that might be produced if sqlite3session_changeset() were
11510** called. The final changeset size might be equal to or smaller than the
11511** size in bytes returned by this function.
11512*/
11513SQLITE_API sqlite3_int64 sqlite3session_changeset_size(sqlite3_session *pSession);
11514
11515/*
11516** CAPI3REF: Load The Difference Between Tables Into A Session
11517** METHOD: sqlite3_session
11518**
11519** If it is not already attached to the session object passed as the first
11520** argument, this function attaches table zTbl in the same manner as the
11521** [sqlite3session_attach()] function. If zTbl does not exist, or if it
11522** does not have a primary key, this function is a no-op (but does not return
11523** an error).
11524**
11525** Argument zFromDb must be the name of a database ("main", "temp" etc.)
11526** attached to the same database handle as the session object that contains
11527** a table compatible with the table attached to the session by this function.
11528** A table is considered compatible if it:
11529**
11530** <ul>
11531** <li> Has the same name,
11532** <li> Has the same set of columns declared in the same order, and
11533** <li> Has the same PRIMARY KEY definition.
11534** </ul>
11535**
11536** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables
11537** are compatible but do not have any PRIMARY KEY columns, it is not an error
11538** but no changes are added to the session object. As with other session
11539** APIs, tables without PRIMARY KEYs are simply ignored.
11540**
11541** This function adds a set of changes to the session object that could be
11542** used to update the table in database zFrom (call this the "from-table")
11543** so that its content is the same as the table attached to the session
11544** object (call this the "to-table"). Specifically:
11545**
11546** <ul>
11547** <li> For each row (primary key) that exists in the to-table but not in
11548** the from-table, an INSERT record is added to the session object.
11549**
11550** <li> For each row (primary key) that exists in the to-table but not in
11551** the from-table, a DELETE record is added to the session object.
11552**
11553** <li> For each row (primary key) that exists in both tables, but features
11554** different non-PK values in each, an UPDATE record is added to the
11555** session.
11556** </ul>
11557**
11558** To clarify, if this function is called and then a changeset constructed
11559** using [sqlite3session_changeset()], then after applying that changeset to
11560** database zFrom the contents of the two compatible tables would be
11561** identical.
11562**
11563** It an error if database zFrom does not exist or does not contain the
11564** required compatible table.
11565**
11566** If the operation is successful, SQLITE_OK is returned. Otherwise, an SQLite
11567** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg
11568** may be set to point to a buffer containing an English language error
11569** message. It is the responsibility of the caller to free this buffer using
11570** sqlite3_free().
11571*/
11572SQLITE_API int sqlite3session_diff(
11573 sqlite3_session *pSession,
11574 const char *zFromDb,
11575 const char *zTbl,
11576 char **pzErrMsg
11577);
11578
11579
11580/*
11581** CAPI3REF: Generate A Patchset From A Session Object
11582** METHOD: sqlite3_session
11583**
11584** The differences between a patchset and a changeset are that:
11585**
11586** <ul>
11587** <li> DELETE records consist of the primary key fields only. The
11588** original values of other fields are omitted.
11589** <li> The original values of any modified fields are omitted from
11590** UPDATE records.
11591** </ul>
11592**
11593** A patchset blob may be used with up to date versions of all
11594** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(),
11595** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly,
11596** attempting to use a patchset blob with old versions of the
11597** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error.
11598**
11599** Because the non-primary key "old.*" fields are omitted, no
11600** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset
11601** is passed to the sqlite3changeset_apply() API. Other conflict types work
11602** in the same way as for changesets.
11603**
11604** Changes within a patchset are ordered in the same way as for changesets
11605** generated by the sqlite3session_changeset() function (i.e. all changes for
11606** a single table are grouped together, tables appear in the order in which
11607** they were attached to the session object).
11608*/
11609SQLITE_API int sqlite3session_patchset(
11610 sqlite3_session *pSession, /* Session object */
11611 int *pnPatchset, /* OUT: Size of buffer at *ppPatchset */
11612 void **ppPatchset /* OUT: Buffer containing patchset */
11613);
11614
11615/*
11616** CAPI3REF: Test if a changeset has recorded any changes.
11617**
11618** Return non-zero if no changes to attached tables have been recorded by
11619** the session object passed as the first argument. Otherwise, if one or
11620** more changes have been recorded, return zero.
11621**
11622** Even if this function returns zero, it is possible that calling
11623** [sqlite3session_changeset()] on the session handle may still return a
11624** changeset that contains no changes. This can happen when a row in
11625** an attached table is modified and then later on the original values
11626** are restored. However, if this function returns non-zero, then it is
11627** guaranteed that a call to sqlite3session_changeset() will return a
11628** changeset containing zero changes.
11629*/
11630SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession);
11631
11632/*
11633** CAPI3REF: Query for the amount of heap memory used by a session object.
11634**
11635** This API returns the total amount of heap memory in bytes currently
11636** used by the session object passed as the only argument.
11637*/
11638SQLITE_API sqlite3_int64 sqlite3session_memory_used(sqlite3_session *pSession);
11639
11640/*
11641** CAPI3REF: Create An Iterator To Traverse A Changeset
11642** CONSTRUCTOR: sqlite3_changeset_iter
11643**
11644** Create an iterator used to iterate through the contents of a changeset.
11645** If successful, *pp is set to point to the iterator handle and SQLITE_OK
11646** is returned. Otherwise, if an error occurs, *pp is set to zero and an
11647** SQLite error code is returned.
11648**
11649** The following functions can be used to advance and query a changeset
11650** iterator created by this function:
11651**
11652** <ul>
11653** <li> [sqlite3changeset_next()]
11654** <li> [sqlite3changeset_op()]
11655** <li> [sqlite3changeset_new()]
11656** <li> [sqlite3changeset_old()]
11657** </ul>
11658**
11659** It is the responsibility of the caller to eventually destroy the iterator
11660** by passing it to [sqlite3changeset_finalize()]. The buffer containing the
11661** changeset (pChangeset) must remain valid until after the iterator is
11662** destroyed.
11663**
11664** Assuming the changeset blob was created by one of the
11665** [sqlite3session_changeset()], [sqlite3changeset_concat()] or
11666** [sqlite3changeset_invert()] functions, all changes within the changeset
11667** that apply to a single table are grouped together. This means that when
11668** an application iterates through a changeset using an iterator created by
11669** this function, all changes that relate to a single table are visited
11670** consecutively. There is no chance that the iterator will visit a change
11671** the applies to table X, then one for table Y, and then later on visit
11672** another change for table X.
11673**
11674** The behavior of sqlite3changeset_start_v2() and its streaming equivalent
11675** may be modified by passing a combination of
11676** [SQLITE_CHANGESETSTART_INVERT | supported flags] as the 4th parameter.
11677**
11678** Note that the sqlite3changeset_start_v2() API is still <b>experimental</b>
11679** and therefore subject to change.
11680*/
11681SQLITE_API int sqlite3changeset_start(
11682 sqlite3_changeset_iter **pp, /* OUT: New changeset iterator handle */
11683 int nChangeset, /* Size of changeset blob in bytes */
11684 void *pChangeset /* Pointer to blob containing changeset */
11685);
11686SQLITE_API int sqlite3changeset_start_v2(
11687 sqlite3_changeset_iter **pp, /* OUT: New changeset iterator handle */
11688 int nChangeset, /* Size of changeset blob in bytes */
11689 void *pChangeset, /* Pointer to blob containing changeset */
11690 int flags /* SESSION_CHANGESETSTART_* flags */
11691);
11692
11693/*
11694** CAPI3REF: Flags for sqlite3changeset_start_v2
11695**
11696** The following flags may passed via the 4th parameter to
11697** [sqlite3changeset_start_v2] and [sqlite3changeset_start_v2_strm]:
11698**
11699** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
11700** Invert the changeset while iterating through it. This is equivalent to
11701** inverting a changeset using sqlite3changeset_invert() before applying it.
11702** It is an error to specify this flag with a patchset.
11703*/
11704#define SQLITE_CHANGESETSTART_INVERT 0x0002
11705
11706
11707/*
11708** CAPI3REF: Advance A Changeset Iterator
11709** METHOD: sqlite3_changeset_iter
11710**
11711** This function may only be used with iterators created by the function
11712** [sqlite3changeset_start()]. If it is called on an iterator passed to
11713** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE
11714** is returned and the call has no effect.
11715**
11716** Immediately after an iterator is created by sqlite3changeset_start(), it
11717** does not point to any change in the changeset. Assuming the changeset
11718** is not empty, the first call to this function advances the iterator to
11719** point to the first change in the changeset. Each subsequent call advances
11720** the iterator to point to the next change in the changeset (if any). If
11721** no error occurs and the iterator points to a valid change after a call
11722** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned.
11723** Otherwise, if all changes in the changeset have already been visited,
11724** SQLITE_DONE is returned.
11725**
11726** If an error occurs, an SQLite error code is returned. Possible error
11727** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or
11728** SQLITE_NOMEM.
11729*/
11730SQLITE_API int sqlite3changeset_next(sqlite3_changeset_iter *pIter);
11731
11732/*
11733** CAPI3REF: Obtain The Current Operation From A Changeset Iterator
11734** METHOD: sqlite3_changeset_iter
11735**
11736** The pIter argument passed to this function may either be an iterator
11737** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
11738** created by [sqlite3changeset_start()]. In the latter case, the most recent
11739** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this
11740** is not the case, this function returns [SQLITE_MISUSE].
11741**
11742** Arguments pOp, pnCol and pzTab may not be NULL. Upon return, three
11743** outputs are set through these pointers:
11744**
11745** *pOp is set to one of [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE],
11746** depending on the type of change that the iterator currently points to;
11747**
11748** *pnCol is set to the number of columns in the table affected by the change; and
11749**
11750** *pzTab is set to point to a nul-terminated utf-8 encoded string containing
11751** the name of the table affected by the current change. The buffer remains
11752** valid until either sqlite3changeset_next() is called on the iterator
11753** or until the conflict-handler function returns.
11754**
11755** If pbIndirect is not NULL, then *pbIndirect is set to true (1) if the change
11756** is an indirect change, or false (0) otherwise. See the documentation for
11757** [sqlite3session_indirect()] for a description of direct and indirect
11758** changes.
11759**
11760** If no error occurs, SQLITE_OK is returned. If an error does occur, an
11761** SQLite error code is returned. The values of the output variables may not
11762** be trusted in this case.
11763*/
11764SQLITE_API int sqlite3changeset_op(
11765 sqlite3_changeset_iter *pIter, /* Iterator object */
11766 const char **pzTab, /* OUT: Pointer to table name */
11767 int *pnCol, /* OUT: Number of columns in table */
11768 int *pOp, /* OUT: SQLITE_INSERT, DELETE or UPDATE */
11769 int *pbIndirect /* OUT: True for an 'indirect' change */
11770);
11771
11772/*
11773** CAPI3REF: Obtain The Primary Key Definition Of A Table
11774** METHOD: sqlite3_changeset_iter
11775**
11776** For each modified table, a changeset includes the following:
11777**
11778** <ul>
11779** <li> The number of columns in the table, and
11780** <li> Which of those columns make up the tables PRIMARY KEY.
11781** </ul>
11782**
11783** This function is used to find which columns comprise the PRIMARY KEY of
11784** the table modified by the change that iterator pIter currently points to.
11785** If successful, *pabPK is set to point to an array of nCol entries, where
11786** nCol is the number of columns in the table. Elements of *pabPK are set to
11787** 0x01 if the corresponding column is part of the tables primary key, or
11788** 0x00 if it is not.
11789**
11790** If argument pnCol is not NULL, then *pnCol is set to the number of columns
11791** in the table.
11792**
11793** If this function is called when the iterator does not point to a valid
11794** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise,
11795** SQLITE_OK is returned and the output variables populated as described
11796** above.
11797*/
11798SQLITE_API int sqlite3changeset_pk(
11799 sqlite3_changeset_iter *pIter, /* Iterator object */
11800 unsigned char **pabPK, /* OUT: Array of boolean - true for PK cols */
11801 int *pnCol /* OUT: Number of entries in output array */
11802);
11803
11804/*
11805** CAPI3REF: Obtain old.* Values From A Changeset Iterator
11806** METHOD: sqlite3_changeset_iter
11807**
11808** The pIter argument passed to this function may either be an iterator
11809** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
11810** created by [sqlite3changeset_start()]. In the latter case, the most recent
11811** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
11812** Furthermore, it may only be called if the type of change that the iterator
11813** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise,
11814** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
11815**
11816** Argument iVal must be greater than or equal to 0, and less than the number
11817** of columns in the table affected by the current change. Otherwise,
11818** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
11819**
11820** If successful, this function sets *ppValue to point to a protected
11821** sqlite3_value object containing the iVal'th value from the vector of
11822** original row values stored as part of the UPDATE or DELETE change and
11823** returns SQLITE_OK. The name of the function comes from the fact that this
11824** is similar to the "old.*" columns available to update or delete triggers.
11825**
11826** If some other error occurs (e.g. an OOM condition), an SQLite error code
11827** is returned and *ppValue is set to NULL.
11828*/
11829SQLITE_API int sqlite3changeset_old(
11830 sqlite3_changeset_iter *pIter, /* Changeset iterator */
11831 int iVal, /* Column number */
11832 sqlite3_value **ppValue /* OUT: Old value (or NULL pointer) */
11833);
11834
11835/*
11836** CAPI3REF: Obtain new.* Values From A Changeset Iterator
11837** METHOD: sqlite3_changeset_iter
11838**
11839** The pIter argument passed to this function may either be an iterator
11840** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
11841** created by [sqlite3changeset_start()]. In the latter case, the most recent
11842** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
11843** Furthermore, it may only be called if the type of change that the iterator
11844** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise,
11845** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
11846**
11847** Argument iVal must be greater than or equal to 0, and less than the number
11848** of columns in the table affected by the current change. Otherwise,
11849** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
11850**
11851** If successful, this function sets *ppValue to point to a protected
11852** sqlite3_value object containing the iVal'th value from the vector of
11853** new row values stored as part of the UPDATE or INSERT change and
11854** returns SQLITE_OK. If the change is an UPDATE and does not include
11855** a new value for the requested column, *ppValue is set to NULL and
11856** SQLITE_OK returned. The name of the function comes from the fact that
11857** this is similar to the "new.*" columns available to update or delete
11858** triggers.
11859**
11860** If some other error occurs (e.g. an OOM condition), an SQLite error code
11861** is returned and *ppValue is set to NULL.
11862*/
11863SQLITE_API int sqlite3changeset_new(
11864 sqlite3_changeset_iter *pIter, /* Changeset iterator */
11865 int iVal, /* Column number */
11866 sqlite3_value **ppValue /* OUT: New value (or NULL pointer) */
11867);
11868
11869/*
11870** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator
11871** METHOD: sqlite3_changeset_iter
11872**
11873** This function should only be used with iterator objects passed to a
11874** conflict-handler callback by [sqlite3changeset_apply()] with either
11875** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function
11876** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue
11877** is set to NULL.
11878**
11879** Argument iVal must be greater than or equal to 0, and less than the number
11880** of columns in the table affected by the current change. Otherwise,
11881** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
11882**
11883** If successful, this function sets *ppValue to point to a protected
11884** sqlite3_value object containing the iVal'th value from the
11885** "conflicting row" associated with the current conflict-handler callback
11886** and returns SQLITE_OK.
11887**
11888** If some other error occurs (e.g. an OOM condition), an SQLite error code
11889** is returned and *ppValue is set to NULL.
11890*/
11891SQLITE_API int sqlite3changeset_conflict(
11892 sqlite3_changeset_iter *pIter, /* Changeset iterator */
11893 int iVal, /* Column number */
11894 sqlite3_value **ppValue /* OUT: Value from conflicting row */
11895);
11896
11897/*
11898** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations
11899** METHOD: sqlite3_changeset_iter
11900**
11901** This function may only be called with an iterator passed to an
11902** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
11903** it sets the output variable to the total number of known foreign key
11904** violations in the destination database and returns SQLITE_OK.
11905**
11906** In all other cases this function returns SQLITE_MISUSE.
11907*/
11908SQLITE_API int sqlite3changeset_fk_conflicts(
11909 sqlite3_changeset_iter *pIter, /* Changeset iterator */
11910 int *pnOut /* OUT: Number of FK violations */
11911);
11912
11913
11914/*
11915** CAPI3REF: Finalize A Changeset Iterator
11916** METHOD: sqlite3_changeset_iter
11917**
11918** This function is used to finalize an iterator allocated with
11919** [sqlite3changeset_start()].
11920**
11921** This function should only be called on iterators created using the
11922** [sqlite3changeset_start()] function. If an application calls this
11923** function with an iterator passed to a conflict-handler by
11924** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the
11925** call has no effect.
11926**
11927** If an error was encountered within a call to an sqlite3changeset_xxx()
11928** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an
11929** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding
11930** to that error is returned by this function. Otherwise, SQLITE_OK is
11931** returned. This is to allow the following pattern (pseudo-code):
11932**
11933** <pre>
11934** sqlite3changeset_start();
11935** while( SQLITE_ROW==sqlite3changeset_next() ){
11936** // Do something with change.
11937** }
11938** rc = sqlite3changeset_finalize();
11939** if( rc!=SQLITE_OK ){
11940** // An error has occurred
11941** }
11942** </pre>
11943*/
11944SQLITE_API int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter);
11945
11946/*
11947** CAPI3REF: Invert A Changeset
11948**
11949** This function is used to "invert" a changeset object. Applying an inverted
11950** changeset to a database reverses the effects of applying the uninverted
11951** changeset. Specifically:
11952**
11953** <ul>
11954** <li> Each DELETE change is changed to an INSERT, and
11955** <li> Each INSERT change is changed to a DELETE, and
11956** <li> For each UPDATE change, the old.* and new.* values are exchanged.
11957** </ul>
11958**
11959** This function does not change the order in which changes appear within
11960** the changeset. It merely reverses the sense of each individual change.
11961**
11962** If successful, a pointer to a buffer containing the inverted changeset
11963** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and
11964** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are
11965** zeroed and an SQLite error code returned.
11966**
11967** It is the responsibility of the caller to eventually call sqlite3_free()
11968** on the *ppOut pointer to free the buffer allocation following a successful
11969** call to this function.
11970**
11971** WARNING/TODO: This function currently assumes that the input is a valid
11972** changeset. If it is not, the results are undefined.
11973*/
11974SQLITE_API int sqlite3changeset_invert(
11975 int nIn, const void *pIn, /* Input changeset */
11976 int *pnOut, void **ppOut /* OUT: Inverse of input */
11977);
11978
11979/*
11980** CAPI3REF: Concatenate Two Changeset Objects
11981**
11982** This function is used to concatenate two changesets, A and B, into a
11983** single changeset. The result is a changeset equivalent to applying
11984** changeset A followed by changeset B.
11985**
11986** This function combines the two input changesets using an
11987** sqlite3_changegroup object. Calling it produces similar results as the
11988** following code fragment:
11989**
11990** <pre>
11991** sqlite3_changegroup *pGrp;
11992** rc = sqlite3_changegroup_new(&pGrp);
11993** if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA);
11994** if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB);
11995** if( rc==SQLITE_OK ){
11996** rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
11997** }else{
11998** *ppOut = 0;
11999** *pnOut = 0;
12000** }
12001** </pre>
12002**
12003** Refer to the sqlite3_changegroup documentation below for details.
12004*/
12005SQLITE_API int sqlite3changeset_concat(
12006 int nA, /* Number of bytes in buffer pA */
12007 void *pA, /* Pointer to buffer containing changeset A */
12008 int nB, /* Number of bytes in buffer pB */
12009 void *pB, /* Pointer to buffer containing changeset B */
12010 int *pnOut, /* OUT: Number of bytes in output changeset */
12011 void **ppOut /* OUT: Buffer containing output changeset */
12012);
12013
12014
12015/*
12016** CAPI3REF: Upgrade the Schema of a Changeset/Patchset
12017*/
12018SQLITE_API int sqlite3changeset_upgrade(
12019 sqlite3 *db,
12020 const char *zDb,
12021 int nIn, const void *pIn, /* Input changeset */
12022 int *pnOut, void **ppOut /* OUT: Inverse of input */
12023);
12024
12025
12026
12027/*
12028** CAPI3REF: Changegroup Handle
12029**
12030** A changegroup is an object used to combine two or more
12031** [changesets] or [patchsets]
12032*/
12033typedef struct sqlite3_changegroup sqlite3_changegroup;
12034
12035/*
12036** CAPI3REF: Create A New Changegroup Object
12037** CONSTRUCTOR: sqlite3_changegroup
12038**
12039** An sqlite3_changegroup object is used to combine two or more changesets
12040** (or patchsets) into a single changeset (or patchset). A single changegroup
12041** object may combine changesets or patchsets, but not both. The output is
12042** always in the same format as the input.
12043**
12044** If successful, this function returns SQLITE_OK and populates (*pp) with
12045** a pointer to a new sqlite3_changegroup object before returning. The caller
12046** should eventually free the returned object using a call to
12047** sqlite3changegroup_delete(). If an error occurs, an SQLite error code
12048** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL.
12049**
12050** The usual usage pattern for an sqlite3_changegroup object is as follows:
12051**
12052** <ul>
12053** <li> It is created using a call to sqlite3changegroup_new().
12054**
12055** <li> Zero or more changesets (or patchsets) are added to the object
12056** by calling sqlite3changegroup_add().
12057**
12058** <li> The result of combining all input changesets together is obtained
12059** by the application via a call to sqlite3changegroup_output().
12060**
12061** <li> The object is deleted using a call to sqlite3changegroup_delete().
12062** </ul>
12063**
12064** Any number of calls to add() and output() may be made between the calls to
12065** new() and delete(), and in any order.
12066**
12067** As well as the regular sqlite3changegroup_add() and
12068** sqlite3changegroup_output() functions, also available are the streaming
12069** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm().
12070*/
12071SQLITE_API int sqlite3changegroup_new(sqlite3_changegroup **pp);
12072
12073/*
12074** CAPI3REF: Add a Schema to a Changegroup
12075** METHOD: sqlite3_changegroup_schema
12076**
12077** This method may be used to optionally enforce the rule that the changesets
12078** added to the changegroup handle must match the schema of database zDb
12079** ("main", "temp", or the name of an attached database). If
12080** sqlite3changegroup_add() is called to add a changeset that is not compatible
12081** with the configured schema, SQLITE_SCHEMA is returned and the changegroup
12082** object is left in an undefined state.
12083**
12084** A changeset schema is considered compatible with the database schema in
12085** the same way as for sqlite3changeset_apply(). Specifically, for each
12086** table in the changeset, there exists a database table with:
12087**
12088** <ul>
12089** <li> The name identified by the changeset, and
12090** <li> at least as many columns as recorded in the changeset, and
12091** <li> the primary key columns in the same position as recorded in
12092** the changeset.
12093** </ul>
12094**
12095** The output of the changegroup object always has the same schema as the
12096** database nominated using this function. In cases where changesets passed
12097** to sqlite3changegroup_add() have fewer columns than the corresponding table
12098** in the database schema, these are filled in using the default column
12099** values from the database schema. This makes it possible to combined
12100** changesets that have different numbers of columns for a single table
12101** within a changegroup, provided that they are otherwise compatible.
12102*/
12103SQLITE_API int sqlite3changegroup_schema(sqlite3_changegroup*, sqlite3*, const char *zDb);
12104
12105/*
12106** CAPI3REF: Add A Changeset To A Changegroup
12107** METHOD: sqlite3_changegroup
12108**
12109** Add all changes within the changeset (or patchset) in buffer pData (size
12110** nData bytes) to the changegroup.
12111**
12112** If the buffer contains a patchset, then all prior calls to this function
12113** on the same changegroup object must also have specified patchsets. Or, if
12114** the buffer contains a changeset, so must have the earlier calls to this
12115** function. Otherwise, SQLITE_ERROR is returned and no changes are added
12116** to the changegroup.
12117**
12118** Rows within the changeset and changegroup are identified by the values in
12119** their PRIMARY KEY columns. A change in the changeset is considered to
12120** apply to the same row as a change already present in the changegroup if
12121** the two rows have the same primary key.
12122**
12123** Changes to rows that do not already appear in the changegroup are
12124** simply copied into it. Or, if both the new changeset and the changegroup
12125** contain changes that apply to a single row, the final contents of the
12126** changegroup depends on the type of each change, as follows:
12127**
12128** <table border=1 style="margin-left:8ex;margin-right:8ex">
12129** <tr><th style="white-space:pre">Existing Change </th>
12130** <th style="white-space:pre">New Change </th>
12131** <th>Output Change
12132** <tr><td>INSERT <td>INSERT <td>
12133** The new change is ignored. This case does not occur if the new
12134** changeset was recorded immediately after the changesets already
12135** added to the changegroup.
12136** <tr><td>INSERT <td>UPDATE <td>
12137** The INSERT change remains in the changegroup. The values in the
12138** INSERT change are modified as if the row was inserted by the
12139** existing change and then updated according to the new change.
12140** <tr><td>INSERT <td>DELETE <td>
12141** The existing INSERT is removed from the changegroup. The DELETE is
12142** not added.
12143** <tr><td>UPDATE <td>INSERT <td>
12144** The new change is ignored. This case does not occur if the new
12145** changeset was recorded immediately after the changesets already
12146** added to the changegroup.
12147** <tr><td>UPDATE <td>UPDATE <td>
12148** The existing UPDATE remains within the changegroup. It is amended
12149** so that the accompanying values are as if the row was updated once
12150** by the existing change and then again by the new change.
12151** <tr><td>UPDATE <td>DELETE <td>
12152** The existing UPDATE is replaced by the new DELETE within the
12153** changegroup.
12154** <tr><td>DELETE <td>INSERT <td>
12155** If one or more of the column values in the row inserted by the
12156** new change differ from those in the row deleted by the existing
12157** change, the existing DELETE is replaced by an UPDATE within the
12158** changegroup. Otherwise, if the inserted row is exactly the same
12159** as the deleted row, the existing DELETE is simply discarded.
12160** <tr><td>DELETE <td>UPDATE <td>
12161** The new change is ignored. This case does not occur if the new
12162** changeset was recorded immediately after the changesets already
12163** added to the changegroup.
12164** <tr><td>DELETE <td>DELETE <td>
12165** The new change is ignored. This case does not occur if the new
12166** changeset was recorded immediately after the changesets already
12167** added to the changegroup.
12168** </table>
12169**
12170** If the new changeset contains changes to a table that is already present
12171** in the changegroup, then the number of columns and the position of the
12172** primary key columns for the table must be consistent. If this is not the
12173** case, this function fails with SQLITE_SCHEMA. Except, if the changegroup
12174** object has been configured with a database schema using the
12175** sqlite3changegroup_schema() API, then it is possible to combine changesets
12176** with different numbers of columns for a single table, provided that
12177** they are otherwise compatible.
12178**
12179** If the input changeset appears to be corrupt and the corruption is
12180** detected, SQLITE_CORRUPT is returned. Or, if an out-of-memory condition
12181** occurs during processing, this function returns SQLITE_NOMEM.
12182**
12183** In all cases, if an error occurs the state of the final contents of the
12184** changegroup is undefined. If no error occurs, SQLITE_OK is returned.
12185*/
12186SQLITE_API int sqlite3changegroup_add(sqlite3_changegroup*, int nData, void *pData);
12187
12188/*
12189** CAPI3REF: Add A Single Change To A Changegroup
12190** METHOD: sqlite3_changegroup
12191**
12192** This function adds the single change currently indicated by the iterator
12193** passed as the second argument to the changegroup object. The rules for
12194** adding the change are just as described for [sqlite3changegroup_add()].
12195**
12196** If the change is successfully added to the changegroup, SQLITE_OK is
12197** returned. Otherwise, an SQLite error code is returned.
12198**
12199** The iterator must point to a valid entry when this function is called.
12200** If it does not, SQLITE_ERROR is returned and no change is added to the
12201** changegroup. Additionally, the iterator must not have been opened with
12202** the SQLITE_CHANGESETAPPLY_INVERT flag. In this case SQLITE_ERROR is also
12203** returned.
12204*/
12205SQLITE_API int sqlite3changegroup_add_change(
12206 sqlite3_changegroup*,
12207 sqlite3_changeset_iter*
12208);
12209
12210
12211
12212/*
12213** CAPI3REF: Obtain A Composite Changeset From A Changegroup
12214** METHOD: sqlite3_changegroup
12215**
12216** Obtain a buffer containing a changeset (or patchset) representing the
12217** current contents of the changegroup. If the inputs to the changegroup
12218** were themselves changesets, the output is a changeset. Or, if the
12219** inputs were patchsets, the output is also a patchset.
12220**
12221** As with the output of the sqlite3session_changeset() and
12222** sqlite3session_patchset() functions, all changes related to a single
12223** table are grouped together in the output of this function. Tables appear
12224** in the same order as for the very first changeset added to the changegroup.
12225** If the second or subsequent changesets added to the changegroup contain
12226** changes for tables that do not appear in the first changeset, they are
12227** appended onto the end of the output changeset, again in the order in
12228** which they are first encountered.
12229**
12230** If an error occurs, an SQLite error code is returned and the output
12231** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK
12232** is returned and the output variables are set to the size of and a
12233** pointer to the output buffer, respectively. In this case it is the
12234** responsibility of the caller to eventually free the buffer using a
12235** call to sqlite3_free().
12236*/
12237SQLITE_API int sqlite3changegroup_output(
12238 sqlite3_changegroup*,
12239 int *pnData, /* OUT: Size of output buffer in bytes */
12240 void **ppData /* OUT: Pointer to output buffer */
12241);
12242
12243/*
12244** CAPI3REF: Delete A Changegroup Object
12245** DESTRUCTOR: sqlite3_changegroup
12246*/
12247SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup*);
12248
12249/*
12250** CAPI3REF: Apply A Changeset To A Database
12251**
12252** Apply a changeset or patchset to a database. These functions attempt to
12253** update the "main" database attached to handle db with the changes found in
12254** the changeset passed via the second and third arguments.
12255**
12256** The fourth argument (xFilter) passed to these functions is the "filter
12257** callback". If it is not NULL, then for each table affected by at least one
12258** change in the changeset, the filter callback is invoked with
12259** the table name as the second argument, and a copy of the context pointer
12260** passed as the sixth argument as the first. If the "filter callback"
12261** returns zero, then no attempt is made to apply any changes to the table.
12262** Otherwise, if the return value is non-zero or the xFilter argument to
12263** is NULL, all changes related to the table are attempted.
12264**
12265** For each table that is not excluded by the filter callback, this function
12266** tests that the target database contains a compatible table. A table is
12267** considered compatible if all of the following are true:
12268**
12269** <ul>
12270** <li> The table has the same name as the name recorded in the
12271** changeset, and
12272** <li> The table has at least as many columns as recorded in the
12273** changeset, and
12274** <li> The table has primary key columns in the same position as
12275** recorded in the changeset.
12276** </ul>
12277**
12278** If there is no compatible table, it is not an error, but none of the
12279** changes associated with the table are applied. A warning message is issued
12280** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most
12281** one such warning is issued for each table in the changeset.
12282**
12283** For each change for which there is a compatible table, an attempt is made
12284** to modify the table contents according to the UPDATE, INSERT or DELETE
12285** change. If a change cannot be applied cleanly, the conflict handler
12286** function passed as the fifth argument to sqlite3changeset_apply() may be
12287** invoked. A description of exactly when the conflict handler is invoked for
12288** each type of change is below.
12289**
12290** Unlike the xFilter argument, xConflict may not be passed NULL. The results
12291** of passing anything other than a valid function pointer as the xConflict
12292** argument are undefined.
12293**
12294** Each time the conflict handler function is invoked, it must return one
12295** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or
12296** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned
12297** if the second argument passed to the conflict handler is either
12298** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler
12299** returns an illegal value, any changes already made are rolled back and
12300** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different
12301** actions are taken by sqlite3changeset_apply() depending on the value
12302** returned by each invocation of the conflict-handler function. Refer to
12303** the documentation for the three
12304** [SQLITE_CHANGESET_OMIT|available return values] for details.
12305**
12306** <dl>
12307** <dt>DELETE Changes<dd>
12308** For each DELETE change, the function checks if the target database
12309** contains a row with the same primary key value (or values) as the
12310** original row values stored in the changeset. If it does, and the values
12311** stored in all non-primary key columns also match the values stored in
12312** the changeset the row is deleted from the target database.
12313**
12314** If a row with matching primary key values is found, but one or more of
12315** the non-primary key fields contains a value different from the original
12316** row value stored in the changeset, the conflict-handler function is
12317** invoked with [SQLITE_CHANGESET_DATA] as the second argument. If the
12318** database table has more columns than are recorded in the changeset,
12319** only the values of those non-primary key fields are compared against
12320** the current database contents - any trailing database table columns
12321** are ignored.
12322**
12323** If no row with matching primary key values is found in the database,
12324** the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
12325** passed as the second argument.
12326**
12327** If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT
12328** (which can only happen if a foreign key constraint is violated), the
12329** conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT]
12330** passed as the second argument. This includes the case where the DELETE
12331** operation is attempted because an earlier call to the conflict handler
12332** function returned [SQLITE_CHANGESET_REPLACE].
12333**
12334** <dt>INSERT Changes<dd>
12335** For each INSERT change, an attempt is made to insert the new row into
12336** the database. If the changeset row contains fewer fields than the
12337** database table, the trailing fields are populated with their default
12338** values.
12339**
12340** If the attempt to insert the row fails because the database already
12341** contains a row with the same primary key values, the conflict handler
12342** function is invoked with the second argument set to
12343** [SQLITE_CHANGESET_CONFLICT].
12344**
12345** If the attempt to insert the row fails because of some other constraint
12346** violation (e.g. NOT NULL or UNIQUE), the conflict handler function is
12347** invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT].
12348** This includes the case where the INSERT operation is re-attempted because
12349** an earlier call to the conflict handler function returned
12350** [SQLITE_CHANGESET_REPLACE].
12351**
12352** <dt>UPDATE Changes<dd>
12353** For each UPDATE change, the function checks if the target database
12354** contains a row with the same primary key value (or values) as the
12355** original row values stored in the changeset. If it does, and the values
12356** stored in all modified non-primary key columns also match the values
12357** stored in the changeset the row is updated within the target database.
12358**
12359** If a row with matching primary key values is found, but one or more of
12360** the modified non-primary key fields contains a value different from an
12361** original row value stored in the changeset, the conflict-handler function
12362** is invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since
12363** UPDATE changes only contain values for non-primary key fields that are
12364** to be modified, only those fields need to match the original values to
12365** avoid the SQLITE_CHANGESET_DATA conflict-handler callback.
12366**
12367** If no row with matching primary key values is found in the database,
12368** the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
12369** passed as the second argument.
12370**
12371** If the UPDATE operation is attempted, but SQLite returns
12372** SQLITE_CONSTRAINT, the conflict-handler function is invoked with
12373** [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument.
12374** This includes the case where the UPDATE operation is attempted after
12375** an earlier call to the conflict handler function returned
12376** [SQLITE_CHANGESET_REPLACE].
12377** </dl>
12378**
12379** It is safe to execute SQL statements, including those that write to the
12380** table that the callback related to, from within the xConflict callback.
12381** This can be used to further customize the application's conflict
12382** resolution strategy.
12383**
12384** All changes made by these functions are enclosed in a savepoint transaction.
12385** If any other error (aside from a constraint failure when attempting to
12386** write to the target database) occurs, then the savepoint transaction is
12387** rolled back, restoring the target database to its original state, and an
12388** SQLite error code returned.
12389**
12390** If the output parameters (ppRebase) and (pnRebase) are non-NULL and
12391** the input is a changeset (not a patchset), then sqlite3changeset_apply_v2()
12392** may set (*ppRebase) to point to a "rebase" that may be used with the
12393** sqlite3_rebaser APIs buffer before returning. In this case (*pnRebase)
12394** is set to the size of the buffer in bytes. It is the responsibility of the
12395** caller to eventually free any such buffer using sqlite3_free(). The buffer
12396** is only allocated and populated if one or more conflicts were encountered
12397** while applying the patchset. See comments surrounding the sqlite3_rebaser
12398** APIs for further details.
12399**
12400** The behavior of sqlite3changeset_apply_v2() and its streaming equivalent
12401** may be modified by passing a combination of
12402** [SQLITE_CHANGESETAPPLY_NOSAVEPOINT | supported flags] as the 9th parameter.
12403**
12404** Note that the sqlite3changeset_apply_v2() API is still <b>experimental</b>
12405** and therefore subject to change.
12406*/
12407SQLITE_API int sqlite3changeset_apply(
12408 sqlite3 *db, /* Apply change to "main" db of this handle */
12409 int nChangeset, /* Size of changeset in bytes */
12410 void *pChangeset, /* Changeset blob */
12411 int(*xFilter)(
12412 void *pCtx, /* Copy of sixth arg to _apply() */
12413 const char *zTab /* Table name */
12414 ),
12415 int(*xConflict)(
12416 void *pCtx, /* Copy of sixth arg to _apply() */
12417 int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */
12418 sqlite3_changeset_iter *p /* Handle describing change and conflict */
12419 ),
12420 void *pCtx /* First argument passed to xConflict */
12421);
12422SQLITE_API int sqlite3changeset_apply_v2(
12423 sqlite3 *db, /* Apply change to "main" db of this handle */
12424 int nChangeset, /* Size of changeset in bytes */
12425 void *pChangeset, /* Changeset blob */
12426 int(*xFilter)(
12427 void *pCtx, /* Copy of sixth arg to _apply() */
12428 const char *zTab /* Table name */
12429 ),
12430 int(*xConflict)(
12431 void *pCtx, /* Copy of sixth arg to _apply() */
12432 int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */
12433 sqlite3_changeset_iter *p /* Handle describing change and conflict */
12434 ),
12435 void *pCtx, /* First argument passed to xConflict */
12436 void **ppRebase, int *pnRebase, /* OUT: Rebase data */
12437 int flags /* SESSION_CHANGESETAPPLY_* flags */
12438);
12439
12440/*
12441** CAPI3REF: Flags for sqlite3changeset_apply_v2
12442**
12443** The following flags may passed via the 9th parameter to
12444** [sqlite3changeset_apply_v2] and [sqlite3changeset_apply_v2_strm]:
12445**
12446** <dl>
12447** <dt>SQLITE_CHANGESETAPPLY_NOSAVEPOINT <dd>
12448** Usually, the sessions module encloses all operations performed by
12449** a single call to apply_v2() or apply_v2_strm() in a [SAVEPOINT]. The
12450** SAVEPOINT is committed if the changeset or patchset is successfully
12451** applied, or rolled back if an error occurs. Specifying this flag
12452** causes the sessions module to omit this savepoint. In this case, if the
12453** caller has an open transaction or savepoint when apply_v2() is called,
12454** it may revert the partially applied changeset by rolling it back.
12455**
12456** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
12457** Invert the changeset before applying it. This is equivalent to inverting
12458** a changeset using sqlite3changeset_invert() before applying it. It is
12459** an error to specify this flag with a patchset.
12460**
12461** <dt>SQLITE_CHANGESETAPPLY_IGNORENOOP <dd>
12462** Do not invoke the conflict handler callback for any changes that
12463** would not actually modify the database even if they were applied.
12464** Specifically, this means that the conflict handler is not invoked
12465** for:
12466** <ul>
12467** <li>a delete change if the row being deleted cannot be found,
12468** <li>an update change if the modified fields are already set to
12469** their new values in the conflicting row, or
12470** <li>an insert change if all fields of the conflicting row match
12471** the row being inserted.
12472** </ul>
12473**
12474** <dt>SQLITE_CHANGESETAPPLY_FKNOACTION <dd>
12475** If this flag it set, then all foreign key constraints in the target
12476** database behave as if they were declared with "ON UPDATE NO ACTION ON
12477** DELETE NO ACTION", even if they are actually CASCADE, RESTRICT, SET NULL
12478** or SET DEFAULT.
12479*/
12480#define SQLITE_CHANGESETAPPLY_NOSAVEPOINT 0x0001
12481#define SQLITE_CHANGESETAPPLY_INVERT 0x0002
12482#define SQLITE_CHANGESETAPPLY_IGNORENOOP 0x0004
12483#define SQLITE_CHANGESETAPPLY_FKNOACTION 0x0008
12484
12485/*
12486** CAPI3REF: Constants Passed To The Conflict Handler
12487**
12488** Values that may be passed as the second argument to a conflict-handler.
12489**
12490** <dl>
12491** <dt>SQLITE_CHANGESET_DATA<dd>
12492** The conflict handler is invoked with CHANGESET_DATA as the second argument
12493** when processing a DELETE or UPDATE change if a row with the required
12494** PRIMARY KEY fields is present in the database, but one or more other
12495** (non primary-key) fields modified by the update do not contain the
12496** expected "before" values.
12497**
12498** The conflicting row, in this case, is the database row with the matching
12499** primary key.
12500**
12501** <dt>SQLITE_CHANGESET_NOTFOUND<dd>
12502** The conflict handler is invoked with CHANGESET_NOTFOUND as the second
12503** argument when processing a DELETE or UPDATE change if a row with the
12504** required PRIMARY KEY fields is not present in the database.
12505**
12506** There is no conflicting row in this case. The results of invoking the
12507** sqlite3changeset_conflict() API are undefined.
12508**
12509** <dt>SQLITE_CHANGESET_CONFLICT<dd>
12510** CHANGESET_CONFLICT is passed as the second argument to the conflict
12511** handler while processing an INSERT change if the operation would result
12512** in duplicate primary key values.
12513**
12514** The conflicting row in this case is the database row with the matching
12515** primary key.
12516**
12517** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd>
12518** If foreign key handling is enabled, and applying a changeset leaves the
12519** database in a state containing foreign key violations, the conflict
12520** handler is invoked with CHANGESET_FOREIGN_KEY as the second argument
12521** exactly once before the changeset is committed. If the conflict handler
12522** returns CHANGESET_OMIT, the changes, including those that caused the
12523** foreign key constraint violation, are committed. Or, if it returns
12524** CHANGESET_ABORT, the changeset is rolled back.
12525**
12526** No current or conflicting row information is provided. The only function
12527** it is possible to call on the supplied sqlite3_changeset_iter handle
12528** is sqlite3changeset_fk_conflicts().
12529**
12530** <dt>SQLITE_CHANGESET_CONSTRAINT<dd>
12531** If any other constraint violation occurs while applying a change (i.e.
12532** a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is
12533** invoked with CHANGESET_CONSTRAINT as the second argument.
12534**
12535** There is no conflicting row in this case. The results of invoking the
12536** sqlite3changeset_conflict() API are undefined.
12537**
12538** </dl>
12539*/
12540#define SQLITE_CHANGESET_DATA 1
12541#define SQLITE_CHANGESET_NOTFOUND 2
12542#define SQLITE_CHANGESET_CONFLICT 3
12543#define SQLITE_CHANGESET_CONSTRAINT 4
12544#define SQLITE_CHANGESET_FOREIGN_KEY 5
12545
12546/*
12547** CAPI3REF: Constants Returned By The Conflict Handler
12548**
12549** A conflict handler callback must return one of the following three values.
12550**
12551** <dl>
12552** <dt>SQLITE_CHANGESET_OMIT<dd>
12553** If a conflict handler returns this value no special action is taken. The
12554** change that caused the conflict is not applied. The session module
12555** continues to the next change in the changeset.
12556**
12557** <dt>SQLITE_CHANGESET_REPLACE<dd>
12558** This value may only be returned if the second argument to the conflict
12559** handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this
12560** is not the case, any changes applied so far are rolled back and the
12561** call to sqlite3changeset_apply() returns SQLITE_MISUSE.
12562**
12563** If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict
12564** handler, then the conflicting row is either updated or deleted, depending
12565** on the type of change.
12566**
12567** If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict
12568** handler, then the conflicting row is removed from the database and a
12569** second attempt to apply the change is made. If this second attempt fails,
12570** the original row is restored to the database before continuing.
12571**
12572** <dt>SQLITE_CHANGESET_ABORT<dd>
12573** If this value is returned, any changes applied so far are rolled back
12574** and the call to sqlite3changeset_apply() returns SQLITE_ABORT.
12575** </dl>
12576*/
12577#define SQLITE_CHANGESET_OMIT 0
12578#define SQLITE_CHANGESET_REPLACE 1
12579#define SQLITE_CHANGESET_ABORT 2
12580
12581/*
12582** CAPI3REF: Rebasing changesets
12583** EXPERIMENTAL
12584**
12585** Suppose there is a site hosting a database in state S0. And that
12586** modifications are made that move that database to state S1 and a
12587** changeset recorded (the "local" changeset). Then, a changeset based
12588** on S0 is received from another site (the "remote" changeset) and
12589** applied to the database. The database is then in state
12590** (S1+"remote"), where the exact state depends on any conflict
12591** resolution decisions (OMIT or REPLACE) made while applying "remote".
12592** Rebasing a changeset is to update it to take those conflict
12593** resolution decisions into account, so that the same conflicts
12594** do not have to be resolved elsewhere in the network.
12595**
12596** For example, if both the local and remote changesets contain an
12597** INSERT of the same key on "CREATE TABLE t1(a PRIMARY KEY, b)":
12598**
12599** local: INSERT INTO t1 VALUES(1, 'v1');
12600** remote: INSERT INTO t1 VALUES(1, 'v2');
12601**
12602** and the conflict resolution is REPLACE, then the INSERT change is
12603** removed from the local changeset (it was overridden). Or, if the
12604** conflict resolution was "OMIT", then the local changeset is modified
12605** to instead contain:
12606**
12607** UPDATE t1 SET b = 'v2' WHERE a=1;
12608**
12609** Changes within the local changeset are rebased as follows:
12610**
12611** <dl>
12612** <dt>Local INSERT<dd>
12613** This may only conflict with a remote INSERT. If the conflict
12614** resolution was OMIT, then add an UPDATE change to the rebased
12615** changeset. Or, if the conflict resolution was REPLACE, add
12616** nothing to the rebased changeset.
12617**
12618** <dt>Local DELETE<dd>
12619** This may conflict with a remote UPDATE or DELETE. In both cases the
12620** only possible resolution is OMIT. If the remote operation was a
12621** DELETE, then add no change to the rebased changeset. If the remote
12622** operation was an UPDATE, then the old.* fields of change are updated
12623** to reflect the new.* values in the UPDATE.
12624**
12625** <dt>Local UPDATE<dd>
12626** This may conflict with a remote UPDATE or DELETE. If it conflicts
12627** with a DELETE, and the conflict resolution was OMIT, then the update
12628** is changed into an INSERT. Any undefined values in the new.* record
12629** from the update change are filled in using the old.* values from
12630** the conflicting DELETE. Or, if the conflict resolution was REPLACE,
12631** the UPDATE change is simply omitted from the rebased changeset.
12632**
12633** If conflict is with a remote UPDATE and the resolution is OMIT, then
12634** the old.* values are rebased using the new.* values in the remote
12635** change. Or, if the resolution is REPLACE, then the change is copied
12636** into the rebased changeset with updates to columns also updated by
12637** the conflicting remote UPDATE removed. If this means no columns would
12638** be updated, the change is omitted.
12639** </dl>
12640**
12641** A local change may be rebased against multiple remote changes
12642** simultaneously. If a single key is modified by multiple remote
12643** changesets, they are combined as follows before the local changeset
12644** is rebased:
12645**
12646** <ul>
12647** <li> If there has been one or more REPLACE resolutions on a
12648** key, it is rebased according to a REPLACE.
12649**
12650** <li> If there have been no REPLACE resolutions on a key, then
12651** the local changeset is rebased according to the most recent
12652** of the OMIT resolutions.
12653** </ul>
12654**
12655** Note that conflict resolutions from multiple remote changesets are
12656** combined on a per-field basis, not per-row. This means that in the
12657** case of multiple remote UPDATE operations, some fields of a single
12658** local change may be rebased for REPLACE while others are rebased for
12659** OMIT.
12660**
12661** In order to rebase a local changeset, the remote changeset must first
12662** be applied to the local database using sqlite3changeset_apply_v2() and
12663** the buffer of rebase information captured. Then:
12664**
12665** <ol>
12666** <li> An sqlite3_rebaser object is created by calling
12667** sqlite3rebaser_create().
12668** <li> The new object is configured with the rebase buffer obtained from
12669** sqlite3changeset_apply_v2() by calling sqlite3rebaser_configure().
12670** If the local changeset is to be rebased against multiple remote
12671** changesets, then sqlite3rebaser_configure() should be called
12672** multiple times, in the same order that the multiple
12673** sqlite3changeset_apply_v2() calls were made.
12674** <li> Each local changeset is rebased by calling sqlite3rebaser_rebase().
12675** <li> The sqlite3_rebaser object is deleted by calling
12676** sqlite3rebaser_delete().
12677** </ol>
12678*/
12679typedef struct sqlite3_rebaser sqlite3_rebaser;
12680
12681/*
12682** CAPI3REF: Create a changeset rebaser object.
12683** EXPERIMENTAL
12684**
12685** Allocate a new changeset rebaser object. If successful, set (*ppNew) to
12686** point to the new object and return SQLITE_OK. Otherwise, if an error
12687** occurs, return an SQLite error code (e.g. SQLITE_NOMEM) and set (*ppNew)
12688** to NULL.
12689*/
12690SQLITE_API int sqlite3rebaser_create(sqlite3_rebaser **ppNew);
12691
12692/*
12693** CAPI3REF: Configure a changeset rebaser object.
12694** EXPERIMENTAL
12695**
12696** Configure the changeset rebaser object to rebase changesets according
12697** to the conflict resolutions described by buffer pRebase (size nRebase
12698** bytes), which must have been obtained from a previous call to
12699** sqlite3changeset_apply_v2().
12700*/
12701SQLITE_API int sqlite3rebaser_configure(
12702 sqlite3_rebaser*,
12703 int nRebase, const void *pRebase
12704);
12705
12706/*
12707** CAPI3REF: Rebase a changeset
12708** EXPERIMENTAL
12709**
12710** Argument pIn must point to a buffer containing a changeset nIn bytes
12711** in size. This function allocates and populates a buffer with a copy
12712** of the changeset rebased according to the configuration of the
12713** rebaser object passed as the first argument. If successful, (*ppOut)
12714** is set to point to the new buffer containing the rebased changeset and
12715** (*pnOut) to its size in bytes and SQLITE_OK returned. It is the
12716** responsibility of the caller to eventually free the new buffer using
12717** sqlite3_free(). Otherwise, if an error occurs, (*ppOut) and (*pnOut)
12718** are set to zero and an SQLite error code returned.
12719*/
12720SQLITE_API int sqlite3rebaser_rebase(
12721 sqlite3_rebaser*,
12722 int nIn, const void *pIn,
12723 int *pnOut, void **ppOut
12724);
12725
12726/*
12727** CAPI3REF: Delete a changeset rebaser object.
12728** EXPERIMENTAL
12729**
12730** Delete the changeset rebaser object and all associated resources. There
12731** should be one call to this function for each successful invocation
12732** of sqlite3rebaser_create().
12733*/
12734SQLITE_API void sqlite3rebaser_delete(sqlite3_rebaser *p);
12735
12736/*
12737** CAPI3REF: Streaming Versions of API functions.
12738**
12739** The six streaming API xxx_strm() functions serve similar purposes to the
12740** corresponding non-streaming API functions:
12741**
12742** <table border=1 style="margin-left:8ex;margin-right:8ex">
12743** <tr><th>Streaming function<th>Non-streaming equivalent</th>
12744** <tr><td>sqlite3changeset_apply_strm<td>[sqlite3changeset_apply]
12745** <tr><td>sqlite3changeset_apply_strm_v2<td>[sqlite3changeset_apply_v2]
12746** <tr><td>sqlite3changeset_concat_strm<td>[sqlite3changeset_concat]
12747** <tr><td>sqlite3changeset_invert_strm<td>[sqlite3changeset_invert]
12748** <tr><td>sqlite3changeset_start_strm<td>[sqlite3changeset_start]
12749** <tr><td>sqlite3session_changeset_strm<td>[sqlite3session_changeset]
12750** <tr><td>sqlite3session_patchset_strm<td>[sqlite3session_patchset]
12751** </table>
12752**
12753** Non-streaming functions that accept changesets (or patchsets) as input
12754** require that the entire changeset be stored in a single buffer in memory.
12755** Similarly, those that return a changeset or patchset do so by returning
12756** a pointer to a single large buffer allocated using sqlite3_malloc().
12757** Normally this is convenient. However, if an application running in a
12758** low-memory environment is required to handle very large changesets, the
12759** large contiguous memory allocations required can become onerous.
12760**
12761** In order to avoid this problem, instead of a single large buffer, input
12762** is passed to a streaming API functions by way of a callback function that
12763** the sessions module invokes to incrementally request input data as it is
12764** required. In all cases, a pair of API function parameters such as
12765**
12766** <pre>
12767** &nbsp; int nChangeset,
12768** &nbsp; void *pChangeset,
12769** </pre>
12770**
12771** Is replaced by:
12772**
12773** <pre>
12774** &nbsp; int (*xInput)(void *pIn, void *pData, int *pnData),
12775** &nbsp; void *pIn,
12776** </pre>
12777**
12778** Each time the xInput callback is invoked by the sessions module, the first
12779** argument passed is a copy of the supplied pIn context pointer. The second
12780** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no
12781** error occurs the xInput method should copy up to (*pnData) bytes of data
12782** into the buffer and set (*pnData) to the actual number of bytes copied
12783** before returning SQLITE_OK. If the input is completely exhausted, (*pnData)
12784** should be set to zero to indicate this. Or, if an error occurs, an SQLite
12785** error code should be returned. In all cases, if an xInput callback returns
12786** an error, all processing is abandoned and the streaming API function
12787** returns a copy of the error code to the caller.
12788**
12789** In the case of sqlite3changeset_start_strm(), the xInput callback may be
12790** invoked by the sessions module at any point during the lifetime of the
12791** iterator. If such an xInput callback returns an error, the iterator enters
12792** an error state, whereby all subsequent calls to iterator functions
12793** immediately fail with the same error code as returned by xInput.
12794**
12795** Similarly, streaming API functions that return changesets (or patchsets)
12796** return them in chunks by way of a callback function instead of via a
12797** pointer to a single large buffer. In this case, a pair of parameters such
12798** as:
12799**
12800** <pre>
12801** &nbsp; int *pnChangeset,
12802** &nbsp; void **ppChangeset,
12803** </pre>
12804**
12805** Is replaced by:
12806**
12807** <pre>
12808** &nbsp; int (*xOutput)(void *pOut, const void *pData, int nData),
12809** &nbsp; void *pOut
12810** </pre>
12811**
12812** The xOutput callback is invoked zero or more times to return data to
12813** the application. The first parameter passed to each call is a copy of the
12814** pOut pointer supplied by the application. The second parameter, pData,
12815** points to a buffer nData bytes in size containing the chunk of output
12816** data being returned. If the xOutput callback successfully processes the
12817** supplied data, it should return SQLITE_OK to indicate success. Otherwise,
12818** it should return some other SQLite error code. In this case processing
12819** is immediately abandoned and the streaming API function returns a copy
12820** of the xOutput error code to the application.
12821**
12822** The sessions module never invokes an xOutput callback with the third
12823** parameter set to a value less than or equal to zero. Other than this,
12824** no guarantees are made as to the size of the chunks of data returned.
12825*/
12826SQLITE_API int sqlite3changeset_apply_strm(
12827 sqlite3 *db, /* Apply change to "main" db of this handle */
12828 int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
12829 void *pIn, /* First arg for xInput */
12830 int(*xFilter)(
12831 void *pCtx, /* Copy of sixth arg to _apply() */
12832 const char *zTab /* Table name */
12833 ),
12834 int(*xConflict)(
12835 void *pCtx, /* Copy of sixth arg to _apply() */
12836 int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */
12837 sqlite3_changeset_iter *p /* Handle describing change and conflict */
12838 ),
12839 void *pCtx /* First argument passed to xConflict */
12840);
12841SQLITE_API int sqlite3changeset_apply_v2_strm(
12842 sqlite3 *db, /* Apply change to "main" db of this handle */
12843 int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
12844 void *pIn, /* First arg for xInput */
12845 int(*xFilter)(
12846 void *pCtx, /* Copy of sixth arg to _apply() */
12847 const char *zTab /* Table name */
12848 ),
12849 int(*xConflict)(
12850 void *pCtx, /* Copy of sixth arg to _apply() */
12851 int eConflict, /* DATA, MISSING, CONFLICT, CONSTRAINT */
12852 sqlite3_changeset_iter *p /* Handle describing change and conflict */
12853 ),
12854 void *pCtx, /* First argument passed to xConflict */
12855 void **ppRebase, int *pnRebase,
12856 int flags
12857);
12858SQLITE_API int sqlite3changeset_concat_strm(
12859 int (*xInputA)(void *pIn, void *pData, int *pnData),
12860 void *pInA,
12861 int (*xInputB)(void *pIn, void *pData, int *pnData),
12862 void *pInB,
12863 int (*xOutput)(void *pOut, const void *pData, int nData),
12864 void *pOut
12865);
12866SQLITE_API int sqlite3changeset_invert_strm(
12867 int (*xInput)(void *pIn, void *pData, int *pnData),
12868 void *pIn,
12869 int (*xOutput)(void *pOut, const void *pData, int nData),
12870 void *pOut
12871);
12872SQLITE_API int sqlite3changeset_start_strm(
12873 sqlite3_changeset_iter **pp,
12874 int (*xInput)(void *pIn, void *pData, int *pnData),
12875 void *pIn
12876);
12877SQLITE_API int sqlite3changeset_start_v2_strm(
12878 sqlite3_changeset_iter **pp,
12879 int (*xInput)(void *pIn, void *pData, int *pnData),
12880 void *pIn,
12881 int flags
12882);
12883SQLITE_API int sqlite3session_changeset_strm(
12884 sqlite3_session *pSession,
12885 int (*xOutput)(void *pOut, const void *pData, int nData),
12886 void *pOut
12887);
12888SQLITE_API int sqlite3session_patchset_strm(
12889 sqlite3_session *pSession,
12890 int (*xOutput)(void *pOut, const void *pData, int nData),
12891 void *pOut
12892);
12893SQLITE_API int sqlite3changegroup_add_strm(sqlite3_changegroup*,
12894 int (*xInput)(void *pIn, void *pData, int *pnData),
12895 void *pIn
12896);
12897SQLITE_API int sqlite3changegroup_output_strm(sqlite3_changegroup*,
12898 int (*xOutput)(void *pOut, const void *pData, int nData),
12899 void *pOut
12900);
12901SQLITE_API int sqlite3rebaser_rebase_strm(
12902 sqlite3_rebaser *pRebaser,
12903 int (*xInput)(void *pIn, void *pData, int *pnData),
12904 void *pIn,
12905 int (*xOutput)(void *pOut, const void *pData, int nData),
12906 void *pOut
12907);
12908
12909/*
12910** CAPI3REF: Configure global parameters
12911**
12912** The sqlite3session_config() interface is used to make global configuration
12913** changes to the sessions module in order to tune it to the specific needs
12914** of the application.
12915**
12916** The sqlite3session_config() interface is not threadsafe. If it is invoked
12917** while any other thread is inside any other sessions method then the
12918** results are undefined. Furthermore, if it is invoked after any sessions
12919** related objects have been created, the results are also undefined.
12920**
12921** The first argument to the sqlite3session_config() function must be one
12922** of the SQLITE_SESSION_CONFIG_XXX constants defined below. The
12923** interpretation of the (void*) value passed as the second parameter and
12924** the effect of calling this function depends on the value of the first
12925** parameter.
12926**
12927** <dl>
12928** <dt>SQLITE_SESSION_CONFIG_STRMSIZE<dd>
12929** By default, the sessions module streaming interfaces attempt to input
12930** and output data in approximately 1 KiB chunks. This operand may be used
12931** to set and query the value of this configuration setting. The pointer
12932** passed as the second argument must point to a value of type (int).
12933** If this value is greater than 0, it is used as the new streaming data
12934** chunk size for both input and output. Before returning, the (int) value
12935** pointed to by pArg is set to the final value of the streaming interface
12936** chunk size.
12937** </dl>
12938**
12939** This function returns SQLITE_OK if successful, or an SQLite error code
12940** otherwise.
12941*/
12942SQLITE_API int sqlite3session_config(int op, void *pArg);
12943
12944/*
12945** CAPI3REF: Values for sqlite3session_config().
12946*/
12947#define SQLITE_SESSION_CONFIG_STRMSIZE 1
12948
12949/*
12950** Make sure we can call this stuff from C++.
12951*/
12952#ifdef __cplusplus
12953}
12954#endif
12955
12956#endif /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */
12957
12958/******** End of sqlite3session.h *********/
12959/******** Begin file fts5.h *********/
12960/*
12961** 2014 May 31
12962**
12963** The author disclaims copyright to this source code. In place of
12964** a legal notice, here is a blessing:
12965**
12966** May you do good and not evil.
12967** May you find forgiveness for yourself and forgive others.
12968** May you share freely, never taking more than you give.
12969**
12970******************************************************************************
12971**
12972** Interfaces to extend FTS5. Using the interfaces defined in this file,
12973** FTS5 may be extended with:
12974**
12975** * custom tokenizers, and
12976** * custom auxiliary functions.
12977*/
12978
12979
12980#ifndef _FTS5_H
12981#define _FTS5_H
12982
12983
12984#ifdef __cplusplus
12985extern "C" {
12986#endif
12987
12988/*************************************************************************
12989** CUSTOM AUXILIARY FUNCTIONS
12990**
12991** Virtual table implementations may overload SQL functions by implementing
12992** the sqlite3_module.xFindFunction() method.
12993*/
12994
12995typedef struct Fts5ExtensionApi Fts5ExtensionApi;
12996typedef struct Fts5Context Fts5Context;
12997typedef struct Fts5PhraseIter Fts5PhraseIter;
12998
12999typedef void (*fts5_extension_function)(
13000 const Fts5ExtensionApi *pApi, /* API offered by current FTS version */
13001 Fts5Context *pFts, /* First arg to pass to pApi functions */
13002 sqlite3_context *pCtx, /* Context for returning result/error */
13003 int nVal, /* Number of values in apVal[] array */
13004 sqlite3_value **apVal /* Array of trailing arguments */
13005);
13006
13007struct Fts5PhraseIter {
13008 const unsigned char *a;
13009 const unsigned char *b;
13010};
13011
13012/*
13013** EXTENSION API FUNCTIONS
13014**
13015** xUserData(pFts):
13016** Return a copy of the pUserData pointer passed to the xCreateFunction()
13017** API when the extension function was registered.
13018**
13019** xColumnTotalSize(pFts, iCol, pnToken):
13020** If parameter iCol is less than zero, set output variable *pnToken
13021** to the total number of tokens in the FTS5 table. Or, if iCol is
13022** non-negative but less than the number of columns in the table, return
13023** the total number of tokens in column iCol, considering all rows in
13024** the FTS5 table.
13025**
13026** If parameter iCol is greater than or equal to the number of columns
13027** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
13028** an OOM condition or IO error), an appropriate SQLite error code is
13029** returned.
13030**
13031** xColumnCount(pFts):
13032** Return the number of columns in the table.
13033**
13034** xColumnSize(pFts, iCol, pnToken):
13035** If parameter iCol is less than zero, set output variable *pnToken
13036** to the total number of tokens in the current row. Or, if iCol is
13037** non-negative but less than the number of columns in the table, set
13038** *pnToken to the number of tokens in column iCol of the current row.
13039**
13040** If parameter iCol is greater than or equal to the number of columns
13041** in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
13042** an OOM condition or IO error), an appropriate SQLite error code is
13043** returned.
13044**
13045** This function may be quite inefficient if used with an FTS5 table
13046** created with the "columnsize=0" option.
13047**
13048** xColumnText:
13049** If parameter iCol is less than zero, or greater than or equal to the
13050** number of columns in the table, SQLITE_RANGE is returned.
13051**
13052** Otherwise, this function attempts to retrieve the text of column iCol of
13053** the current document. If successful, (*pz) is set to point to a buffer
13054** containing the text in utf-8 encoding, (*pn) is set to the size in bytes
13055** (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
13056** if an error occurs, an SQLite error code is returned and the final values
13057** of (*pz) and (*pn) are undefined.
13058**
13059** xPhraseCount:
13060** Returns the number of phrases in the current query expression.
13061**
13062** xPhraseSize:
13063** If parameter iCol is less than zero, or greater than or equal to the
13064** number of phrases in the current query, as returned by xPhraseCount,
13065** 0 is returned. Otherwise, this function returns the number of tokens in
13066** phrase iPhrase of the query. Phrases are numbered starting from zero.
13067**
13068** xInstCount:
13069** Set *pnInst to the total number of occurrences of all phrases within
13070** the query within the current row. Return SQLITE_OK if successful, or
13071** an error code (i.e. SQLITE_NOMEM) if an error occurs.
13072**
13073** This API can be quite slow if used with an FTS5 table created with the
13074** "detail=none" or "detail=column" option. If the FTS5 table is created
13075** with either "detail=none" or "detail=column" and "content=" option
13076** (i.e. if it is a contentless table), then this API always returns 0.
13077**
13078** xInst:
13079** Query for the details of phrase match iIdx within the current row.
13080** Phrase matches are numbered starting from zero, so the iIdx argument
13081** should be greater than or equal to zero and smaller than the value
13082** output by xInstCount(). If iIdx is less than zero or greater than
13083** or equal to the value returned by xInstCount(), SQLITE_RANGE is returned.
13084**
13085** Otherwise, output parameter *piPhrase is set to the phrase number, *piCol
13086** to the column in which it occurs and *piOff the token offset of the
13087** first token of the phrase. SQLITE_OK is returned if successful, or an
13088** error code (i.e. SQLITE_NOMEM) if an error occurs.
13089**
13090** This API can be quite slow if used with an FTS5 table created with the
13091** "detail=none" or "detail=column" option.
13092**
13093** xRowid:
13094** Returns the rowid of the current row.
13095**
13096** xTokenize:
13097** Tokenize text using the tokenizer belonging to the FTS5 table.
13098**
13099** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
13100** This API function is used to query the FTS table for phrase iPhrase
13101** of the current query. Specifically, a query equivalent to:
13102**
13103** ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
13104**
13105** with $p set to a phrase equivalent to the phrase iPhrase of the
13106** current query is executed. Any column filter that applies to
13107** phrase iPhrase of the current query is included in $p. For each
13108** row visited, the callback function passed as the fourth argument
13109** is invoked. The context and API objects passed to the callback
13110** function may be used to access the properties of each matched row.
13111** Invoking Api.xUserData() returns a copy of the pointer passed as
13112** the third argument to pUserData.
13113**
13114** If parameter iPhrase is less than zero, or greater than or equal to
13115** the number of phrases in the query, as returned by xPhraseCount(),
13116** this function returns SQLITE_RANGE.
13117**
13118** If the callback function returns any value other than SQLITE_OK, the
13119** query is abandoned and the xQueryPhrase function returns immediately.
13120** If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
13121** Otherwise, the error code is propagated upwards.
13122**
13123** If the query runs to completion without incident, SQLITE_OK is returned.
13124** Or, if some error occurs before the query completes or is aborted by
13125** the callback, an SQLite error code is returned.
13126**
13127**
13128** xSetAuxdata(pFts5, pAux, xDelete)
13129**
13130** Save the pointer passed as the second argument as the extension function's
13131** "auxiliary data". The pointer may then be retrieved by the current or any
13132** future invocation of the same fts5 extension function made as part of
13133** the same MATCH query using the xGetAuxdata() API.
13134**
13135** Each extension function is allocated a single auxiliary data slot for
13136** each FTS query (MATCH expression). If the extension function is invoked
13137** more than once for a single FTS query, then all invocations share a
13138** single auxiliary data context.
13139**
13140** If there is already an auxiliary data pointer when this function is
13141** invoked, then it is replaced by the new pointer. If an xDelete callback
13142** was specified along with the original pointer, it is invoked at this
13143** point.
13144**
13145** The xDelete callback, if one is specified, is also invoked on the
13146** auxiliary data pointer after the FTS5 query has finished.
13147**
13148** If an error (e.g. an OOM condition) occurs within this function,
13149** the auxiliary data is set to NULL and an error code returned. If the
13150** xDelete parameter was not NULL, it is invoked on the auxiliary data
13151** pointer before returning.
13152**
13153**
13154** xGetAuxdata(pFts5, bClear)
13155**
13156** Returns the current auxiliary data pointer for the fts5 extension
13157** function. See the xSetAuxdata() method for details.
13158**
13159** If the bClear argument is non-zero, then the auxiliary data is cleared
13160** (set to NULL) before this function returns. In this case the xDelete,
13161** if any, is not invoked.
13162**
13163**
13164** xRowCount(pFts5, pnRow)
13165**
13166** This function is used to retrieve the total number of rows in the table.
13167** In other words, the same value that would be returned by:
13168**
13169** SELECT count(*) FROM ftstable;
13170**
13171** xPhraseFirst()
13172** This function is used, along with type Fts5PhraseIter and the xPhraseNext
13173** method, to iterate through all instances of a single query phrase within
13174** the current row. This is the same information as is accessible via the
13175** xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
13176** to use, this API may be faster under some circumstances. To iterate
13177** through instances of phrase iPhrase, use the following code:
13178**
13179** Fts5PhraseIter iter;
13180** int iCol, iOff;
13181** for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
13182** iCol>=0;
13183** pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
13184** ){
13185** // An instance of phrase iPhrase at offset iOff of column iCol
13186** }
13187**
13188** The Fts5PhraseIter structure is defined above. Applications should not
13189** modify this structure directly - it should only be used as shown above
13190** with the xPhraseFirst() and xPhraseNext() API methods (and by
13191** xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
13192**
13193** This API can be quite slow if used with an FTS5 table created with the
13194** "detail=none" or "detail=column" option. If the FTS5 table is created
13195** with either "detail=none" or "detail=column" and "content=" option
13196** (i.e. if it is a contentless table), then this API always iterates
13197** through an empty set (all calls to xPhraseFirst() set iCol to -1).
13198**
13199** In all cases, matches are visited in (column ASC, offset ASC) order.
13200** i.e. all those in column 0, sorted by offset, followed by those in
13201** column 1, etc.
13202**
13203** xPhraseNext()
13204** See xPhraseFirst above.
13205**
13206** xPhraseFirstColumn()
13207** This function and xPhraseNextColumn() are similar to the xPhraseFirst()
13208** and xPhraseNext() APIs described above. The difference is that instead
13209** of iterating through all instances of a phrase in the current row, these
13210** APIs are used to iterate through the set of columns in the current row
13211** that contain one or more instances of a specified phrase. For example:
13212**
13213** Fts5PhraseIter iter;
13214** int iCol;
13215** for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
13216** iCol>=0;
13217** pApi->xPhraseNextColumn(pFts, &iter, &iCol)
13218** ){
13219** // Column iCol contains at least one instance of phrase iPhrase
13220** }
13221**
13222** This API can be quite slow if used with an FTS5 table created with the
13223** "detail=none" option. If the FTS5 table is created with either
13224** "detail=none" "content=" option (i.e. if it is a contentless table),
13225** then this API always iterates through an empty set (all calls to
13226** xPhraseFirstColumn() set iCol to -1).
13227**
13228** The information accessed using this API and its companion
13229** xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
13230** (or xInst/xInstCount). The chief advantage of this API is that it is
13231** significantly more efficient than those alternatives when used with
13232** "detail=column" tables.
13233**
13234** xPhraseNextColumn()
13235** See xPhraseFirstColumn above.
13236**
13237** xQueryToken(pFts5, iPhrase, iToken, ppToken, pnToken)
13238** This is used to access token iToken of phrase iPhrase of the current
13239** query. Before returning, output parameter *ppToken is set to point
13240** to a buffer containing the requested token, and *pnToken to the
13241** size of this buffer in bytes.
13242**
13243** If iPhrase or iToken are less than zero, or if iPhrase is greater than
13244** or equal to the number of phrases in the query as reported by
13245** xPhraseCount(), or if iToken is equal to or greater than the number of
13246** tokens in the phrase, SQLITE_RANGE is returned and *ppToken and *pnToken
13247 are both zeroed.
13248**
13249** The output text is not a copy of the query text that specified the
13250** token. It is the output of the tokenizer module. For tokendata=1
13251** tables, this includes any embedded 0x00 and trailing data.
13252**
13253** xInstToken(pFts5, iIdx, iToken, ppToken, pnToken)
13254** This is used to access token iToken of phrase hit iIdx within the
13255** current row. If iIdx is less than zero or greater than or equal to the
13256** value returned by xInstCount(), SQLITE_RANGE is returned. Otherwise,
13257** output variable (*ppToken) is set to point to a buffer containing the
13258** matching document token, and (*pnToken) to the size of that buffer in
13259** bytes.
13260**
13261** The output text is not a copy of the document text that was tokenized.
13262** It is the output of the tokenizer module. For tokendata=1 tables, this
13263** includes any embedded 0x00 and trailing data.
13264**
13265** This API may be slow in some cases if the token identified by parameters
13266** iIdx and iToken matched a prefix token in the query. In most cases, the
13267** first call to this API for each prefix token in the query is forced
13268** to scan the portion of the full-text index that matches the prefix
13269** token to collect the extra data required by this API. If the prefix
13270** token matches a large number of token instances in the document set,
13271** this may be a performance problem.
13272**
13273** If the user knows in advance that a query may use this API for a
13274** prefix token, FTS5 may be configured to collect all required data as part
13275** of the initial querying of the full-text index, avoiding the second scan
13276** entirely. This also causes prefix queries that do not use this API to
13277** run more slowly and use more memory. FTS5 may be configured in this way
13278** either on a per-table basis using the [FTS5 insttoken | 'insttoken']
13279** option, or on a per-query basis using the
13280** [fts5_insttoken | fts5_insttoken()] user function.
13281**
13282** This API can be quite slow if used with an FTS5 table created with the
13283** "detail=none" or "detail=column" option.
13284**
13285** xColumnLocale(pFts5, iIdx, pzLocale, pnLocale)
13286** If parameter iCol is less than zero, or greater than or equal to the
13287** number of columns in the table, SQLITE_RANGE is returned.
13288**
13289** Otherwise, this function attempts to retrieve the locale associated
13290** with column iCol of the current row. Usually, there is no associated
13291** locale, and output parameters (*pzLocale) and (*pnLocale) are set
13292** to NULL and 0, respectively. However, if the fts5_locale() function
13293** was used to associate a locale with the value when it was inserted
13294** into the fts5 table, then (*pzLocale) is set to point to a nul-terminated
13295** buffer containing the name of the locale in utf-8 encoding. (*pnLocale)
13296** is set to the size in bytes of the buffer, not including the
13297** nul-terminator.
13298**
13299** If successful, SQLITE_OK is returned. Or, if an error occurs, an
13300** SQLite error code is returned. The final value of the output parameters
13301** is undefined in this case.
13302**
13303** xTokenize_v2:
13304** Tokenize text using the tokenizer belonging to the FTS5 table. This
13305** API is the same as the xTokenize() API, except that it allows a tokenizer
13306** locale to be specified.
13307*/
13308struct Fts5ExtensionApi {
13309 int iVersion; /* Currently always set to 4 */
13310
13311 void *(*xUserData)(Fts5Context*);
13312
13313 int (*xColumnCount)(Fts5Context*);
13314 int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
13315 int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
13316
13317 int (*xTokenize)(Fts5Context*,
13318 const char *pText, int nText, /* Text to tokenize */
13319 void *pCtx, /* Context passed to xToken() */
13320 int (*xToken)(void*, int, const char*, int, int, int) /* Callback */
13321 );
13322
13323 int (*xPhraseCount)(Fts5Context*);
13324 int (*xPhraseSize)(Fts5Context*, int iPhrase);
13325
13326 int (*xInstCount)(Fts5Context*, int *pnInst);
13327 int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
13328
13329 sqlite3_int64 (*xRowid)(Fts5Context*);
13330 int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
13331 int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
13332
13333 int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
13334 int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
13335 );
13336 int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
13337 void *(*xGetAuxdata)(Fts5Context*, int bClear);
13338
13339 int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
13340 void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
13341
13342 int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
13343 void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
13344
13345 /* Below this point are iVersion>=3 only */
13346 int (*xQueryToken)(Fts5Context*,
13347 int iPhrase, int iToken,
13348 const char **ppToken, int *pnToken
13349 );
13350 int (*xInstToken)(Fts5Context*, int iIdx, int iToken, const char**, int*);
13351
13352 /* Below this point are iVersion>=4 only */
13353 int (*xColumnLocale)(Fts5Context*, int iCol, const char **pz, int *pn);
13354 int (*xTokenize_v2)(Fts5Context*,
13355 const char *pText, int nText, /* Text to tokenize */
13356 const char *pLocale, int nLocale, /* Locale to pass to tokenizer */
13357 void *pCtx, /* Context passed to xToken() */
13358 int (*xToken)(void*, int, const char*, int, int, int) /* Callback */
13359 );
13360};
13361
13362/*
13363** CUSTOM AUXILIARY FUNCTIONS
13364*************************************************************************/
13365
13366/*************************************************************************
13367** CUSTOM TOKENIZERS
13368**
13369** Applications may also register custom tokenizer types. A tokenizer
13370** is registered by providing fts5 with a populated instance of the
13371** following structure. All structure methods must be defined, setting
13372** any member of the fts5_tokenizer struct to NULL leads to undefined
13373** behaviour. The structure methods are expected to function as follows:
13374**
13375** xCreate:
13376** This function is used to allocate and initialize a tokenizer instance.
13377** A tokenizer instance is required to actually tokenize text.
13378**
13379** The first argument passed to this function is a copy of the (void*)
13380** pointer provided by the application when the fts5_tokenizer_v2 object
13381** was registered with FTS5 (the third argument to xCreateTokenizer()).
13382** The second and third arguments are an array of nul-terminated strings
13383** containing the tokenizer arguments, if any, specified following the
13384** tokenizer name as part of the CREATE VIRTUAL TABLE statement used
13385** to create the FTS5 table.
13386**
13387** The final argument is an output variable. If successful, (*ppOut)
13388** should be set to point to the new tokenizer handle and SQLITE_OK
13389** returned. If an error occurs, some value other than SQLITE_OK should
13390** be returned. In this case, fts5 assumes that the final value of *ppOut
13391** is undefined.
13392**
13393** xDelete:
13394** This function is invoked to delete a tokenizer handle previously
13395** allocated using xCreate(). Fts5 guarantees that this function will
13396** be invoked exactly once for each successful call to xCreate().
13397**
13398** xTokenize:
13399** This function is expected to tokenize the nText byte string indicated
13400** by argument pText. pText may or may not be nul-terminated. The first
13401** argument passed to this function is a pointer to an Fts5Tokenizer object
13402** returned by an earlier call to xCreate().
13403**
13404** The third argument indicates the reason that FTS5 is requesting
13405** tokenization of the supplied text. This is always one of the following
13406** four values:
13407**
13408** <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
13409** or removed from the FTS table. The tokenizer is being invoked to
13410** determine the set of tokens to add to (or delete from) the
13411** FTS index.
13412**
13413** <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
13414** against the FTS index. The tokenizer is being called to tokenize
13415** a bareword or quoted string specified as part of the query.
13416**
13417** <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
13418** FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
13419** followed by a "*" character, indicating that the last token
13420** returned by the tokenizer will be treated as a token prefix.
13421**
13422** <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
13423** satisfy an fts5_api.xTokenize() request made by an auxiliary
13424** function. Or an fts5_api.xColumnSize() request made by the same
13425** on a columnsize=0 database.
13426** </ul>
13427**
13428** The sixth and seventh arguments passed to xTokenize() - pLocale and
13429** nLocale - are a pointer to a buffer containing the locale to use for
13430** tokenization (e.g. "en_US") and its size in bytes, respectively. The
13431** pLocale buffer is not nul-terminated. pLocale may be passed NULL (in
13432** which case nLocale is always 0) to indicate that the tokenizer should
13433** use its default locale.
13434**
13435** For each token in the input string, the supplied callback xToken() must
13436** be invoked. The first argument to it should be a copy of the pointer
13437** passed as the second argument to xTokenize(). The third and fourth
13438** arguments are a pointer to a buffer containing the token text, and the
13439** size of the token in bytes. The 4th and 5th arguments are the byte offsets
13440** of the first byte of and first byte immediately following the text from
13441** which the token is derived within the input.
13442**
13443** The second argument passed to the xToken() callback ("tflags") should
13444** normally be set to 0. The exception is if the tokenizer supports
13445** synonyms. In this case see the discussion below for details.
13446**
13447** FTS5 assumes the xToken() callback is invoked for each token in the
13448** order that they occur within the input text.
13449**
13450** If an xToken() callback returns any value other than SQLITE_OK, then
13451** the tokenization should be abandoned and the xTokenize() method should
13452** immediately return a copy of the xToken() return value. Or, if the
13453** input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
13454** if an error occurs with the xTokenize() implementation itself, it
13455** may abandon the tokenization and return any error code other than
13456** SQLITE_OK or SQLITE_DONE.
13457**
13458** If the tokenizer is registered using an fts5_tokenizer_v2 object,
13459** then the xTokenize() method has two additional arguments - pLocale
13460** and nLocale. These specify the locale that the tokenizer should use
13461** for the current request. If pLocale and nLocale are both 0, then the
13462** tokenizer should use its default locale. Otherwise, pLocale points to
13463** an nLocale byte buffer containing the name of the locale to use as utf-8
13464** text. pLocale is not nul-terminated.
13465**
13466** FTS5_TOKENIZER
13467**
13468** There is also an fts5_tokenizer object. This is an older, deprecated,
13469** version of fts5_tokenizer_v2. It is similar except that:
13470**
13471** <ul>
13472** <li> There is no "iVersion" field, and
13473** <li> The xTokenize() method does not take a locale argument.
13474** </ul>
13475**
13476** Legacy fts5_tokenizer tokenizers must be registered using the
13477** legacy xCreateTokenizer() function, instead of xCreateTokenizer_v2().
13478**
13479** Tokenizer implementations registered using either API may be retrieved
13480** using both xFindTokenizer() and xFindTokenizer_v2().
13481**
13482** SYNONYM SUPPORT
13483**
13484** Custom tokenizers may also support synonyms. Consider a case in which a
13485** user wishes to query for a phrase such as "first place". Using the
13486** built-in tokenizers, the FTS5 query 'first + place' will match instances
13487** of "first place" within the document set, but not alternative forms
13488** such as "1st place". In some applications, it would be better to match
13489** all instances of "first place" or "1st place" regardless of which form
13490** the user specified in the MATCH query text.
13491**
13492** There are several ways to approach this in FTS5:
13493**
13494** <ol><li> By mapping all synonyms to a single token. In this case, using
13495** the above example, this means that the tokenizer returns the
13496** same token for inputs "first" and "1st". Say that token is in
13497** fact "first", so that when the user inserts the document "I won
13498** 1st place" entries are added to the index for tokens "i", "won",
13499** "first" and "place". If the user then queries for '1st + place',
13500** the tokenizer substitutes "first" for "1st" and the query works
13501** as expected.
13502**
13503** <li> By querying the index for all synonyms of each query term
13504** separately. In this case, when tokenizing query text, the
13505** tokenizer may provide multiple synonyms for a single term
13506** within the document. FTS5 then queries the index for each
13507** synonym individually. For example, faced with the query:
13508**
13509** <codeblock>
13510** ... MATCH 'first place'</codeblock>
13511**
13512** the tokenizer offers both "1st" and "first" as synonyms for the
13513** first token in the MATCH query and FTS5 effectively runs a query
13514** similar to:
13515**
13516** <codeblock>
13517** ... MATCH '(first OR 1st) place'</codeblock>
13518**
13519** except that, for the purposes of auxiliary functions, the query
13520** still appears to contain just two phrases - "(first OR 1st)"
13521** being treated as a single phrase.
13522**
13523** <li> By adding multiple synonyms for a single term to the FTS index.
13524** Using this method, when tokenizing document text, the tokenizer
13525** provides multiple synonyms for each token. So that when a
13526** document such as "I won first place" is tokenized, entries are
13527** added to the FTS index for "i", "won", "first", "1st" and
13528** "place".
13529**
13530** This way, even if the tokenizer does not provide synonyms
13531** when tokenizing query text (it should not - to do so would be
13532** inefficient), it doesn't matter if the user queries for
13533** 'first + place' or '1st + place', as there are entries in the
13534** FTS index corresponding to both forms of the first token.
13535** </ol>
13536**
13537** Whether it is parsing document or query text, any call to xToken that
13538** specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
13539** is considered to supply a synonym for the previous token. For example,
13540** when parsing the document "I won first place", a tokenizer that supports
13541** synonyms would call xToken() 5 times, as follows:
13542**
13543** <codeblock>
13544** xToken(pCtx, 0, "i", 1, 0, 1);
13545** xToken(pCtx, 0, "won", 3, 2, 5);
13546** xToken(pCtx, 0, "first", 5, 6, 11);
13547** xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3, 6, 11);
13548** xToken(pCtx, 0, "place", 5, 12, 17);
13549**</codeblock>
13550**
13551** It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
13552** xToken() is called. Multiple synonyms may be specified for a single token
13553** by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
13554** There is no limit to the number of synonyms that may be provided for a
13555** single token.
13556**
13557** In many cases, method (1) above is the best approach. It does not add
13558** extra data to the FTS index or require FTS5 to query for multiple terms,
13559** so it is efficient in terms of disk space and query speed. However, it
13560** does not support prefix queries very well. If, as suggested above, the
13561** token "first" is substituted for "1st" by the tokenizer, then the query:
13562**
13563** <codeblock>
13564** ... MATCH '1s*'</codeblock>
13565**
13566** will not match documents that contain the token "1st" (as the tokenizer
13567** will probably not map "1s" to any prefix of "first").
13568**
13569** For full prefix support, method (3) may be preferred. In this case,
13570** because the index contains entries for both "first" and "1st", prefix
13571** queries such as 'fi*' or '1s*' will match correctly. However, because
13572** extra entries are added to the FTS index, this method uses more space
13573** within the database.
13574**
13575** Method (2) offers a midpoint between (1) and (3). Using this method,
13576** a query such as '1s*' will match documents that contain the literal
13577** token "1st", but not "first" (assuming the tokenizer is not able to
13578** provide synonyms for prefixes). However, a non-prefix query like '1st'
13579** will match against "1st" and "first". This method does not require
13580** extra disk space, as no extra entries are added to the FTS index.
13581** On the other hand, it may require more CPU cycles to run MATCH queries,
13582** as separate queries of the FTS index are required for each synonym.
13583**
13584** When using methods (2) or (3), it is important that the tokenizer only
13585** provide synonyms when tokenizing document text (method (3)) or query
13586** text (method (2)), not both. Doing so will not cause any errors, but is
13587** inefficient.
13588*/
13589typedef struct Fts5Tokenizer Fts5Tokenizer;
13590typedef struct fts5_tokenizer_v2 fts5_tokenizer_v2;
13591struct fts5_tokenizer_v2 {
13592 int iVersion; /* Currently always 2 */
13593
13594 int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
13595 void (*xDelete)(Fts5Tokenizer*);
13596 int (*xTokenize)(Fts5Tokenizer*,
13597 void *pCtx,
13598 int flags, /* Mask of FTS5_TOKENIZE_* flags */
13599 const char *pText, int nText,
13600 const char *pLocale, int nLocale,
13601 int (*xToken)(
13602 void *pCtx, /* Copy of 2nd argument to xTokenize() */
13603 int tflags, /* Mask of FTS5_TOKEN_* flags */
13604 const char *pToken, /* Pointer to buffer containing token */
13605 int nToken, /* Size of token in bytes */
13606 int iStart, /* Byte offset of token within input text */
13607 int iEnd /* Byte offset of end of token within input text */
13608 )
13609 );
13610};
13611
13612/*
13613** New code should use the fts5_tokenizer_v2 type to define tokenizer
13614** implementations. The following type is included for legacy applications
13615** that still use it.
13616*/
13617typedef struct fts5_tokenizer fts5_tokenizer;
13618struct fts5_tokenizer {
13619 int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
13620 void (*xDelete)(Fts5Tokenizer*);
13621 int (*xTokenize)(Fts5Tokenizer*,
13622 void *pCtx,
13623 int flags, /* Mask of FTS5_TOKENIZE_* flags */
13624 const char *pText, int nText,
13625 int (*xToken)(
13626 void *pCtx, /* Copy of 2nd argument to xTokenize() */
13627 int tflags, /* Mask of FTS5_TOKEN_* flags */
13628 const char *pToken, /* Pointer to buffer containing token */
13629 int nToken, /* Size of token in bytes */
13630 int iStart, /* Byte offset of token within input text */
13631 int iEnd /* Byte offset of end of token within input text */
13632 )
13633 );
13634};
13635
13636
13637/* Flags that may be passed as the third argument to xTokenize() */
13638#define FTS5_TOKENIZE_QUERY 0x0001
13639#define FTS5_TOKENIZE_PREFIX 0x0002
13640#define FTS5_TOKENIZE_DOCUMENT 0x0004
13641#define FTS5_TOKENIZE_AUX 0x0008
13642
13643/* Flags that may be passed by the tokenizer implementation back to FTS5
13644** as the third argument to the supplied xToken callback. */
13645#define FTS5_TOKEN_COLOCATED 0x0001 /* Same position as prev. token */
13646
13647/*
13648** END OF CUSTOM TOKENIZERS
13649*************************************************************************/
13650
13651/*************************************************************************
13652** FTS5 EXTENSION REGISTRATION API
13653*/
13654typedef struct fts5_api fts5_api;
13655struct fts5_api {
13656 int iVersion; /* Currently always set to 3 */
13657
13658 /* Create a new tokenizer */
13659 int (*xCreateTokenizer)(
13660 fts5_api *pApi,
13661 const char *zName,
13662 void *pUserData,
13663 fts5_tokenizer *pTokenizer,
13664 void (*xDestroy)(void*)
13665 );
13666
13667 /* Find an existing tokenizer */
13668 int (*xFindTokenizer)(
13669 fts5_api *pApi,
13670 const char *zName,
13671 void **ppUserData,
13672 fts5_tokenizer *pTokenizer
13673 );
13674
13675 /* Create a new auxiliary function */
13676 int (*xCreateFunction)(
13677 fts5_api *pApi,
13678 const char *zName,
13679 void *pUserData,
13680 fts5_extension_function xFunction,
13681 void (*xDestroy)(void*)
13682 );
13683
13684 /* APIs below this point are only available if iVersion>=3 */
13685
13686 /* Create a new tokenizer */
13687 int (*xCreateTokenizer_v2)(
13688 fts5_api *pApi,
13689 const char *zName,
13690 void *pUserData,
13691 fts5_tokenizer_v2 *pTokenizer,
13692 void (*xDestroy)(void*)
13693 );
13694
13695 /* Find an existing tokenizer */
13696 int (*xFindTokenizer_v2)(
13697 fts5_api *pApi,
13698 const char *zName,
13699 void **ppUserData,
13700 fts5_tokenizer_v2 **ppTokenizer
13701 );
13702};
13703
13704/*
13705** END OF REGISTRATION API
13706*************************************************************************/
13707
13708#ifdef __cplusplus
13709} /* end of the 'extern "C"' block */
13710#endif
13711
13712#endif /* _FTS5_H */
13713
13714/******** End of fts5.h *********/
13715#endif /* SQLITE3_H */
13716

source code of qtbase/src/3rdparty/sqlite/sqlite3.h