2** This file is an amalgamation of many separate C source files from SQLite
3** version 3.39.2. By combining all the individual C code files into this
4** single large file, the entire code can be compiled as a single translation
5** unit. This allows many compilers to do optimizations that would not be
6** possible if the files were compiled separately. Performance improvements
7** of 5% or more are commonly seen when SQLite is compiled as a single
8** translation unit.
10** This file is all you need to compile SQLite. To use SQLite in other
11** programs, you need this file and the "sqlite3.h" header file that defines
12** the programming interface to the SQLite library. (If you do not have
13** the "sqlite3.h" header file at hand, you will find a copy embedded within
14** the text of this file. Search for "Begin file sqlite3.h" to find the start
15** of the embedded sqlite3.h header file.) Additional code files may be needed
16** if you want a wrapper to interface SQLite with your choice of programming
17** language. The code for the "sqlite3" command-line shell is also in a
18** separate file. This file contains only code for the core SQLite library.
20#define SQLITE_CORE 1
23# define SQLITE_PRIVATE static
25/************** Begin file sqliteInt.h ***************************************/
27** 2001 September 15
29** The author disclaims copyright to this source code. In place of
30** a legal notice, here is a blessing:
32** May you do good and not evil.
33** May you find forgiveness for yourself and forgive others.
34** May you share freely, never taking more than you give.
37** Internal interface definitions for SQLite.
40#ifndef SQLITEINT_H
41#define SQLITEINT_H
43/* Special Comments:
45** Some comments have special meaning to the tools that measure test
46** coverage:
48** NO_TEST - The branches on this line are not
49** measured by branch coverage. This is
50** used on lines of code that actually
51** implement parts of coverage testing.
53** OPTIMIZATION-IF-TRUE - This branch is allowed to alway be false
54** and the correct answer is still obtained,
55** though perhaps more slowly.
57** OPTIMIZATION-IF-FALSE - This branch is allowed to alway be true
58** and the correct answer is still obtained,
59** though perhaps more slowly.
61** PREVENTS-HARMLESS-OVERREAD - This branch prevents a buffer overread
62** that would be harmless and undetectable
63** if it did occur.
65** In all cases, the special comment must be enclosed in the usual
66** slash-asterisk...asterisk-slash comment marks, with no spaces between the
67** asterisks and the comment text.
71** Make sure the Tcl calling convention macro is defined. This macro is
72** only used by test code and Tcl integration code.
75# define SQLITE_TCLAPI
79** Include the header file used to customize the compiler options for MSVC.
80** This should be done first so that it can successfully prevent spurious
81** compiler warnings due to subsequent content in this file and other files
82** that are included by this file.
84/************** Include msvc.h in the middle of sqliteInt.h ******************/
85/************** Begin file msvc.h ********************************************/
87** 2015 January 12
89** The author disclaims copyright to this source code. In place of
90** a legal notice, here is a blessing:
92** May you do good and not evil.
93** May you find forgiveness for yourself and forgive others.
94** May you share freely, never taking more than you give.
98** This file contains code that is specific to MSVC.
100#ifndef SQLITE_MSVC_H
101#define SQLITE_MSVC_H
103#if defined(_MSC_VER)
104#pragma warning(disable : 4054)
105#pragma warning(disable : 4055)
106#pragma warning(disable : 4100)
107#pragma warning(disable : 4127)
108#pragma warning(disable : 4130)
109#pragma warning(disable : 4152)
110#pragma warning(disable : 4189)
111#pragma warning(disable : 4206)
112#pragma warning(disable : 4210)
113#pragma warning(disable : 4232)
114#pragma warning(disable : 4244)
115#pragma warning(disable : 4305)
116#pragma warning(disable : 4306)
117#pragma warning(disable : 4702)
118#pragma warning(disable : 4706)
119#endif /* defined(_MSC_VER) */
121#if defined(_MSC_VER) && !defined(_WIN64)
124#endif /* defined(_MSC_VER) && !defined(_WIN64) */
126#endif /* SQLITE_MSVC_H */
128/************** End of msvc.h ************************************************/
129/************** Continuing where we left off in sqliteInt.h ******************/
132** Special setup for VxWorks
134/************** Include vxworks.h in the middle of sqliteInt.h ***************/
135/************** Begin file vxworks.h *****************************************/
137** 2015-03-02
139** The author disclaims copyright to this source code. In place of
140** a legal notice, here is a blessing:
142** May you do good and not evil.
143** May you find forgiveness for yourself and forgive others.
144** May you share freely, never taking more than you give.
148** This file contains code that is specific to Wind River's VxWorks
150#if defined(__RTP__) || defined(_WRS_KERNEL)
151/* This is VxWorks. Set up things specially for that OS
153#include <vxWorks.h>
154#include <pthread.h> /* amalgamator: dontcache */
155#define OS_VXWORKS 1
156#define SQLITE_OS_OTHER 0
160#define HAVE_UTIME 1
162/* This is not VxWorks. */
163#define OS_VXWORKS 0
164#define HAVE_FCHOWN 1
165#define HAVE_READLINK 1
166#define HAVE_LSTAT 1
167#endif /* defined(_WRS_KERNEL) */
169/************** End of vxworks.h *********************************************/
170/************** Continuing where we left off in sqliteInt.h ******************/
173** These #defines should enable >2GB file support on POSIX if the
174** underlying operating system supports it. If the OS lacks
175** large file support, or if the OS is windows, these should be no-ops.
177** Ticket #2739: The _LARGEFILE_SOURCE macro must appear before any
178** system #includes. Hence, this block of code must be the very first
179** code in all source files.
181** Large file support can be disabled using the -DSQLITE_DISABLE_LFS switch
182** on the compiler command line. This is necessary if you are compiling
183** on a recent machine (ex: Red Hat 7.2) but you want your code to work
184** on an older machine (ex: Red Hat 6.0). If you compile on Red Hat 7.2
185** without this option, LFS is enable. But LFS does not exist in the kernel
186** in Red Hat 6.0, so the code won't work. Hence, for maximum binary
187** portability you should omit LFS.
189** The previous paragraph was written in 2005. (This paragraph is written
190** on 2008-11-28.) These days, all Linux kernels support large files, so
191** you should probably leave LFS enabled. But some embedded platforms might
192** lack LFS in which case the SQLITE_DISABLE_LFS macro might still be useful.
194** Similar is true for Mac OS X. LFS is only supported on Mac OS X 9 and later.
197# define _LARGE_FILE 1
198# ifndef _FILE_OFFSET_BITS
199# define _FILE_OFFSET_BITS 64
200# endif
201# define _LARGEFILE_SOURCE 1
204/* The GCC_VERSION and MSVC_VERSION macros are used to
205** conditionally include optimizations for each of these compilers. A
206** value of 0 means that compiler is not being used. The
207** SQLITE_DISABLE_INTRINSIC macro means do not use any compiler-specific
208** optimizations, and hence set all compiler macros to 0
210** There was once also a CLANG_VERSION macro. However, we learn that the
211** version numbers in clang are for "marketing" only and are inconsistent
212** and unreliable. Fortunately, all versions of clang also recognize the
213** gcc version numbers and have reasonable settings for gcc version numbers,
214** so the GCC_VERSION macro will be set to a correct non-zero value even
215** when compiling with clang.
217#if defined(__GNUC__) && !defined(SQLITE_DISABLE_INTRINSIC)
218# define GCC_VERSION (__GNUC__*1000000+__GNUC_MINOR__*1000+__GNUC_PATCHLEVEL__)
220# define GCC_VERSION 0
222#if defined(_MSC_VER) && !defined(SQLITE_DISABLE_INTRINSIC)
225# define MSVC_VERSION 0
229** Some C99 functions in "math.h" are only present for MSVC when its version
230** is associated with Visual Studio 2013 or higher.
233# if MSVC_VERSION==0 || MSVC_VERSION>=1800
234# define SQLITE_HAVE_C99_MATH_FUNCS (1)
235# else
236# define SQLITE_HAVE_C99_MATH_FUNCS (0)
237# endif
240/* Needed for various definitions... */
241#if defined(__GNUC__) && !defined(_GNU_SOURCE)
242# define _GNU_SOURCE
245#if defined(__OpenBSD__) && !defined(_BSD_SOURCE)
246# define _BSD_SOURCE
250** Macro to disable warnings about missing "break" at the end of a "case".
252#if GCC_VERSION>=7000000
253# define deliberate_fall_through __attribute__((fallthrough));
255# define deliberate_fall_through
259** For MinGW, check to see if we can include the header file containing its
260** version information, among other things. Normally, this internal MinGW
261** header file would [only] be included automatically by other MinGW header
262** files; however, the contained version information is now required by this
263** header file to work around binary compatibility issues (see below) and
264** this is the only known way to reliably obtain it. This entire #if block
265** would be completely unnecessary if there was any other way of detecting
266** MinGW via their preprocessor (e.g. if they customized their GCC to define
267** some MinGW-specific macros). When compiling for MinGW, either the
268** _HAVE_MINGW_H or _HAVE__MINGW_H (note the extra underscore) macro must be
269** defined; otherwise, detection of conditions specific to MinGW will be
270** disabled.
272#if defined(_HAVE_MINGW_H)
273# include "mingw.h"
274#elif defined(_HAVE__MINGW_H)
275# include "_mingw.h"
279** For MinGW version 4.x (and higher), check to see if the _USE_32BIT_TIME_T
280** define is required to maintain binary compatibility with the MSVC runtime
281** library in use (e.g. for Windows XP).
283#if !defined(_USE_32BIT_TIME_T) && !defined(_USE_64BIT_TIME_T) && \
284 defined(_WIN32) && !defined(_WIN64) && \
285 defined(__MINGW_MAJOR_VERSION) && __MINGW_MAJOR_VERSION >= 4 && \
286 defined(__MSVCRT__)
287# define _USE_32BIT_TIME_T
290/* Optionally #include a user-defined header, whereby compilation options
291** may be set prior to where they take effect, but after platform setup.
292** If SQLITE_CUSTOM_INCLUDE=? is defined, its value names the #include
293** file.
296# define INC_STRINGIFY_(f) #f
301/* The public SQLite interface. The _FILE_OFFSET_BITS macro must appear
302** first in QNX. Also, the _USE_32BIT_TIME_T macro must appear first for
303** MinGW.
305/************** Include sqlite3.h in the middle of sqliteInt.h ***************/
306/************** Begin file sqlite3.h *****************************************/
308** 2001-09-15
310** The author disclaims copyright to this source code. In place of
311** a legal notice, here is a blessing:
313** May you do good and not evil.
314** May you find forgiveness for yourself and forgive others.
315** May you share freely, never taking more than you give.
318** This header file defines the interface that the SQLite library
319** presents to client programs. If a C-function, structure, datatype,
320** or constant definition does not appear in this file, then it is
321** not a published API of SQLite, is subject to change without
322** notice, and should not be referenced by programs that use SQLite.
324** Some of the definitions that are in this file are marked as
325** "experimental". Experimental interfaces are normally new
326** features recently added to SQLite. We do not anticipate changes
327** to experimental interfaces but reserve the right to make minor changes
328** if experience from use "in the wild" suggest such changes are prudent.
330** The official C-language API documentation for SQLite is derived
331** from comments in this file. This file is the authoritative source
332** on how SQLite interfaces are supposed to operate.
334** The name of this file under configuration management is "sqlite.h.in".
335** The makefile makes some minor changes to this file (such as inserting
336** the version number) and changes its name to "sqlite3.h" as
337** part of the build process.
339#ifndef SQLITE3_H
340#define SQLITE3_H
341#include <stdarg.h> /* Needed for the definition of va_list */
344** Make sure we can call this stuff from C++.
346#if 0
347extern "C" {
352** Facilitate override of interface linkage and calling conventions.
353** Be aware that these macros may not be used within this particular
354** translation of the amalgamation and its associated header file.
356** The SQLITE_EXTERN and SQLITE_API macros are used to instruct the
357** compiler that the target identifier should have external linkage.
359** The SQLITE_CDECL macro is used to set the calling convention for
360** public functions that accept a variable number of arguments.
362** The SQLITE_APICALL macro is used to set the calling convention for
363** public functions that accept a fixed number of arguments.
365** The SQLITE_STDCALL macro is no longer used and is now deprecated.
367** The SQLITE_CALLBACK macro is used to set the calling convention for
368** function pointers.
370** The SQLITE_SYSAPI macro is used to set the calling convention for
371** functions provided by the operating system.
374** SQLITE_SYSAPI macros are used only when building for environments
375** that require non-default calling conventions.
377#ifndef SQLITE_EXTERN
378# define SQLITE_EXTERN extern
380#ifndef SQLITE_API
381# define SQLITE_API
383#ifndef SQLITE_CDECL
384# define SQLITE_CDECL
387# define SQLITE_APICALL
395#ifndef SQLITE_SYSAPI
396# define SQLITE_SYSAPI
400** These no-op macros are used in front of interfaces to mark those
401** interfaces as either deprecated or experimental. New applications
402** should not use deprecated interfaces - they are supported for backwards
403** compatibility only. Application writers should be aware that
404** experimental interfaces are subject to change in point releases.
406** These macros used to resolve to various kinds of compiler magic that
407** would generate warning messages when they were used. But that
408** compiler magic ended up generating such a flurry of bug reports
409** that we have taken it all out and gone back to using simple
410** noop macros.
416** Ensure these symbols were not defined by some previous header file.
426** CAPI3REF: Compile-Time Library Version Numbers
428** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
429** evaluates to a string literal that is the SQLite version in the
430** format "X.Y.Z" where X is the major version number (always 3 for
431** SQLite3) and Y is the minor version number and Z is the release number.)^
432** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
433** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
434** numbers used in [SQLITE_VERSION].)^
435** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
436** be larger than the release from which it is derived. Either Y will
437** be held constant and Z will be incremented or else Y will be incremented
438** and Z will be reset to zero.
440** Since [version 3.6.18] ([dateof:3.6.18]),
441** SQLite source code has been stored in the
442** <a href="http://www.fossil-scm.org/">Fossil configuration management
443** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to
444** a string which identifies a particular check-in of SQLite
445** within its configuration management system. ^The SQLITE_SOURCE_ID
446** string contains the date and time of the check-in (UTC) and a SHA1
447** or SHA3-256 hash of the entire source tree. If the source code has
448** been edited in any way since it was last checked in, then the last
449** four hexadecimal digits of the hash may be modified.
451** See also: [sqlite3_libversion()],
452** [sqlite3_libversion_number()], [sqlite3_sourceid()],
453** [sqlite_version()] and [sqlite_source_id()].
455#define SQLITE_VERSION "3.39.2"
456#define SQLITE_VERSION_NUMBER 3039002
457#define SQLITE_SOURCE_ID "2022-07-21 15:24:47 698edb77537b67c41adc68f9b892db56bcf9a55e00371a61420f3ddd668e6603"
460** CAPI3REF: Run-Time Library Version Numbers
461** KEYWORDS: sqlite3_version sqlite3_sourceid
463** These interfaces provide the same information as the [SQLITE_VERSION],
464** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
465** but are associated with the library instead of the header file. ^(Cautious
466** programmers might include assert() statements in their application to
467** verify that values returned by these interfaces match the macros in
468** the header, and thus ensure that the application is
469** compiled with matching library and header files.
471** <blockquote><pre>
472** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
473** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
474** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
475** </pre></blockquote>)^
477** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
478** macro. ^The sqlite3_libversion() function returns a pointer to the
479** to the sqlite3_version[] string constant. The sqlite3_libversion()
480** function is provided for use in DLLs since DLL users usually do not have
481** direct access to string constants within the DLL. ^The
482** sqlite3_libversion_number() function returns an integer equal to
483** [SQLITE_VERSION_NUMBER]. ^(The sqlite3_sourceid() function returns
484** a pointer to a string constant whose value is the same as the
485** [SQLITE_SOURCE_ID] C preprocessor macro. Except if SQLite is built
486** using an edited copy of [the amalgamation], then the last four characters
487** of the hash might be different from [SQLITE_SOURCE_ID].)^
489** See also: [sqlite_version()] and [sqlite_source_id()].
491SQLITE_API const char sqlite3_version[] = SQLITE_VERSION;
492SQLITE_API const char *sqlite3_libversion(void);
493SQLITE_API const char *sqlite3_sourceid(void);
494SQLITE_API int sqlite3_libversion_number(void);
497** CAPI3REF: Run-Time Library Compilation Options Diagnostics
499** ^The sqlite3_compileoption_used() function returns 0 or 1
500** indicating whether the specified option was defined at
501** compile time. ^The SQLITE_ prefix may be omitted from the
502** option name passed to sqlite3_compileoption_used().
504** ^The sqlite3_compileoption_get() function allows iterating
505** over the list of options that were defined at compile time by
506** returning the N-th compile time option string. ^If N is out of range,
507** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_
508** prefix is omitted from any strings returned by
509** sqlite3_compileoption_get().
511** ^Support for the diagnostic functions sqlite3_compileoption_used()
512** and sqlite3_compileoption_get() may be omitted by specifying the
513** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
515** See also: SQL functions [sqlite_compileoption_used()] and
516** [sqlite_compileoption_get()] and the [compile_options pragma].
519SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
520SQLITE_API const char *sqlite3_compileoption_get(int N);
522# define sqlite3_compileoption_used(X) 0
523# define sqlite3_compileoption_get(X) ((void*)0)
527** CAPI3REF: Test To See If The Library Is Threadsafe
529** ^The sqlite3_threadsafe() function returns zero if and only if
530** SQLite was compiled with mutexing code omitted due to the
531** [SQLITE_THREADSAFE] compile-time option being set to 0.
533** SQLite can be compiled with or without mutexes. When
534** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
535** are enabled and SQLite is threadsafe. When the
536** [SQLITE_THREADSAFE] macro is 0,
537** the mutexes are omitted. Without the mutexes, it is not safe
538** to use SQLite concurrently from more than one thread.
540** Enabling mutexes incurs a measurable performance penalty.
541** So if speed is of utmost importance, it makes sense to disable
542** the mutexes. But for maximum safety, mutexes should be enabled.
543** ^The default behavior is for mutexes to be enabled.
545** This interface can be used by an application to make sure that the
546** version of SQLite that it is linking against was compiled with
547** the desired setting of the [SQLITE_THREADSAFE] macro.
549** This interface only reports on the compile-time mutex setting
550** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with
551** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
552** can be fully or partially disabled using a call to [sqlite3_config()]
554** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the
555** sqlite3_threadsafe() function shows only the compile-time setting of
556** thread safety, not any run-time changes to that setting made by
557** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
558** is unchanged by calls to sqlite3_config().)^
560** See the [threading mode] documentation for additional information.
562SQLITE_API int sqlite3_threadsafe(void);
565** CAPI3REF: Database Connection Handle
566** KEYWORDS: {database connection} {database connections}
568** Each open SQLite database is represented by a pointer to an instance of
569** the opaque structure named "sqlite3". It is useful to think of an sqlite3
570** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and
571** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
572** and [sqlite3_close_v2()] are its destructors. There are many other
573** interfaces (such as
574** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
575** [sqlite3_busy_timeout()] to name but three) that are methods on an
576** sqlite3 object.
578typedef struct sqlite3 sqlite3;
581** CAPI3REF: 64-Bit Integer Types
582** KEYWORDS: sqlite_int64 sqlite_uint64
584** Because there is no cross-platform way to specify 64-bit integer types
585** SQLite includes typedefs for 64-bit signed and unsigned integers.
587** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
588** The sqlite_int64 and sqlite_uint64 types are supported for backwards
589** compatibility only.
591** ^The sqlite3_int64 and sqlite_int64 types can store integer values
592** between -9223372036854775808 and +9223372036854775807 inclusive. ^The
593** sqlite3_uint64 and sqlite_uint64 types can store integer values
594** between 0 and +18446744073709551615 inclusive.
596#ifdef SQLITE_INT64_TYPE
597 typedef SQLITE_INT64_TYPE sqlite_int64;
598# ifdef SQLITE_UINT64_TYPE
599 typedef SQLITE_UINT64_TYPE sqlite_uint64;
600# else
601 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
602# endif
603#elif defined(_MSC_VER) || defined(__BORLANDC__)
604 typedef __int64 sqlite_int64;
605 typedef unsigned __int64 sqlite_uint64;
607 typedef long long int sqlite_int64;
608 typedef unsigned long long int sqlite_uint64;
610typedef sqlite_int64 sqlite3_int64;
611typedef sqlite_uint64 sqlite3_uint64;
614** If compiling for a processor that lacks floating point support,
615** substitute integer for floating-point.
618# define double sqlite3_int64
622** CAPI3REF: Closing A Database Connection
623** DESTRUCTOR: sqlite3
625** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
626** for the [sqlite3] object.
627** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
628** the [sqlite3] object is successfully destroyed and all associated
629** resources are deallocated.
631** Ideally, applications should [sqlite3_finalize | finalize] all
632** [prepared statements], [sqlite3_blob_close | close] all [BLOB handles], and
633** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
634** with the [sqlite3] object prior to attempting to close the object.
635** ^If the database connection is associated with unfinalized prepared
636** statements, BLOB handlers, and/or unfinished sqlite3_backup objects then
637** sqlite3_close() will leave the database connection open and return
638** [SQLITE_BUSY]. ^If sqlite3_close_v2() is called with unfinalized prepared
639** statements, unclosed BLOB handlers, and/or unfinished sqlite3_backups,
640** it returns [SQLITE_OK] regardless, but instead of deallocating the database
641** connection immediately, it marks the database connection as an unusable
642** "zombie" and makes arrangements to automatically deallocate the database
643** connection after all prepared statements are finalized, all BLOB handles
644** are closed, and all backups have finished. The sqlite3_close_v2() interface
645** is intended for use with host languages that are garbage collected, and
646** where the order in which destructors are called is arbitrary.
648** ^If an [sqlite3] object is destroyed while a transaction is open,
649** the transaction is automatically rolled back.
651** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
652** must be either a NULL
653** pointer or an [sqlite3] object pointer obtained
654** from [sqlite3_open()], [sqlite3_open16()], or
655** [sqlite3_open_v2()], and not previously closed.
656** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
657** argument is a harmless no-op.
659SQLITE_API int sqlite3_close(sqlite3*);
660SQLITE_API int sqlite3_close_v2(sqlite3*);
663** The type for a callback function.
664** This is legacy and deprecated. It is included for historical
665** compatibility and is not documented.
667typedef int (*sqlite3_callback)(void*,int,char**, char**);
670** CAPI3REF: One-Step Query Execution Interface
671** METHOD: sqlite3
673** The sqlite3_exec() interface is a convenience wrapper around
674** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
675** that allows an application to run multiple statements of SQL
676** without having to use a lot of C code.
678** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
679** semicolon-separate SQL statements passed into its 2nd argument,
680** in the context of the [database connection] passed in as its 1st
681** argument. ^If the callback function of the 3rd argument to
682** sqlite3_exec() is not NULL, then it is invoked for each result row
683** coming out of the evaluated SQL statements. ^The 4th argument to
684** sqlite3_exec() is relayed through to the 1st argument of each
685** callback invocation. ^If the callback pointer to sqlite3_exec()
686** is NULL, then no callback is ever invoked and result rows are
687** ignored.
689** ^If an error occurs while evaluating the SQL statements passed into
690** sqlite3_exec(), then execution of the current statement stops and
691** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec()
692** is not NULL then any error message is written into memory obtained
693** from [sqlite3_malloc()] and passed back through the 5th parameter.
694** To avoid memory leaks, the application should invoke [sqlite3_free()]
695** on error message strings returned through the 5th parameter of
696** sqlite3_exec() after the error message string is no longer needed.
697** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
698** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
699** NULL before returning.
701** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
702** routine returns SQLITE_ABORT without invoking the callback again and
703** without running any subsequent SQL statements.
705** ^The 2nd argument to the sqlite3_exec() callback function is the
706** number of columns in the result. ^The 3rd argument to the sqlite3_exec()
707** callback is an array of pointers to strings obtained as if from
708** [sqlite3_column_text()], one for each column. ^If an element of a
709** result row is NULL then the corresponding string pointer for the
710** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the
711** sqlite3_exec() callback is an array of pointers to strings where each
712** entry represents the name of corresponding result column as obtained
713** from [sqlite3_column_name()].
715** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
716** to an empty string, or a pointer that contains only whitespace and/or
717** SQL comments, then no SQL statements are evaluated and the database
718** is not changed.
720** Restrictions:
722** <ul>
723** <li> The application must ensure that the 1st parameter to sqlite3_exec()
724** is a valid and open [database connection].
725** <li> The application must not close the [database connection] specified by
726** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
727** <li> The application must not modify the SQL statement text passed into
728** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
729** </ul>
731SQLITE_API int sqlite3_exec(
732 sqlite3*, /* An open database */
733 const char *sql, /* SQL to be evaluated */
734 int (*callback)(void*,int,char**,char**), /* Callback function */
735 void *, /* 1st argument to callback */
736 char **errmsg /* Error msg written here */
740** CAPI3REF: Result Codes
741** KEYWORDS: {result code definitions}
743** Many SQLite functions return an integer result code from the set shown
744** here in order to indicate success or failure.
746** New error codes may be added in future versions of SQLite.
748** See also: [extended result code definitions]
750#define SQLITE_OK 0 /* Successful result */
751/* beginning-of-error-codes */
752#define SQLITE_ERROR 1 /* Generic error */
753#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
754#define SQLITE_PERM 3 /* Access permission denied */
755#define SQLITE_ABORT 4 /* Callback routine requested an abort */
756#define SQLITE_BUSY 5 /* The database file is locked */
757#define SQLITE_LOCKED 6 /* A table in the database is locked */
758#define SQLITE_NOMEM 7 /* A malloc() failed */
759#define SQLITE_READONLY 8 /* Attempt to write a readonly database */
760#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
761#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
762#define SQLITE_CORRUPT 11 /* The database disk image is malformed */
763#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
764#define SQLITE_FULL 13 /* Insertion failed because database is full */
765#define SQLITE_CANTOPEN 14 /* Unable to open the database file */
766#define SQLITE_PROTOCOL 15 /* Database lock protocol error */
767#define SQLITE_EMPTY 16 /* Internal use only */
768#define SQLITE_SCHEMA 17 /* The database schema changed */
769#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
770#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
771#define SQLITE_MISMATCH 20 /* Data type mismatch */
772#define SQLITE_MISUSE 21 /* Library used incorrectly */
773#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
774#define SQLITE_AUTH 23 /* Authorization denied */
775#define SQLITE_FORMAT 24 /* Not used */
776#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
777#define SQLITE_NOTADB 26 /* File opened that is not a database file */
778#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */
779#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */
780#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
781#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
782/* end-of-error-codes */
785** CAPI3REF: Extended Result Codes
786** KEYWORDS: {extended result code definitions}
788** In its default configuration, SQLite API routines return one of 30 integer
789** [result codes]. However, experience has shown that many of
790** these result codes are too coarse-grained. They do not provide as
791** much information about problems as programmers might like. In an effort to
792** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8]
793** and later) include
794** support for additional result codes that provide more detailed information
795** about errors. These [extended result codes] are enabled or disabled
796** on a per database connection basis using the
797** [sqlite3_extended_result_codes()] API. Or, the extended code for
798** the most recent error can be obtained using
799** [sqlite3_extended_errcode()].
804#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
815#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
818#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
819#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
825#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
827#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8))
830#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8))
831#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8))
835#define SQLITE_IOERR_DATA (SQLITE_IOERR | (32<<8))
846#define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) /* Not Used */
873#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8))
875#define SQLITE_OK_SYMLINK (SQLITE_OK | (2<<8)) /* internal use only */
878** CAPI3REF: Flags For File Open Operations
880** These bit values are intended for use in the
881** 3rd parameter to the [sqlite3_open_v2()] interface and
882** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
884** Only those flags marked as "Ok for sqlite3_open_v2()" may be
885** used as the third argument to the [sqlite3_open_v2()] interface.
886** The other flags have historically been ignored by sqlite3_open_v2(),
887** though future versions of SQLite might change so that an error is
888** raised if any of the disallowed bits are passed into sqlite3_open_v2().
889** Applications should not depend on the historical behavior.
891** Note in particular that passing the SQLITE_OPEN_EXCLUSIVE flag into
892** [sqlite3_open_v2()] does *not* cause the underlying database file
893** to be opened using O_EXCL. Passing SQLITE_OPEN_EXCLUSIVE into
894** [sqlite3_open_v2()] has historically be a no-op and might become an
895** error in future versions of SQLite.
897#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
898#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
899#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
900#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
901#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
902#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
903#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
904#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
905#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
906#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
907#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
908#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
909#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
910#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
911#define SQLITE_OPEN_SUPER_JOURNAL 0x00004000 /* VFS only */
912#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
913#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
914#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
915#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
916#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
917#define SQLITE_OPEN_NOFOLLOW 0x01000000 /* Ok for sqlite3_open_v2() */
918#define SQLITE_OPEN_EXRESCODE 0x02000000 /* Extended result codes */
920/* Reserved: 0x00F00000 */
921/* Legacy compatibility: */
922#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */
926** CAPI3REF: Device Characteristics
928** The xDeviceCharacteristics method of the [sqlite3_io_methods]
929** object returns an integer which is a vector of these
930** bit values expressing I/O characteristics of the mass storage
931** device that holds the file that the [sqlite3_io_methods]
932** refers to.
934** The SQLITE_IOCAP_ATOMIC property means that all writes of
935** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
936** mean that writes of blocks that are nnn bytes in size and
937** are aligned to an address which is an integer multiple of
938** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
939** that when data is appended to a file, the data is appended
940** first then the size of the file is extended, never the other
941** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
942** information is written to disk in the same order as calls
943** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
944** after reboot following a crash or power loss, the only bytes in a
945** file that were written at the application level might have changed
946** and that adjacent bytes, even bytes within the same sector are
947** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
948** flag indicates that a file cannot be deleted when open. The
949** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
950** read-only media and cannot be changed even by processes with
951** elevated privileges.
953** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
954** filesystem supports doing multiple write operations atomically when those
955** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
958#define SQLITE_IOCAP_ATOMIC 0x00000001
959#define SQLITE_IOCAP_ATOMIC512 0x00000002
960#define SQLITE_IOCAP_ATOMIC1K 0x00000004
961#define SQLITE_IOCAP_ATOMIC2K 0x00000008
962#define SQLITE_IOCAP_ATOMIC4K 0x00000010
963#define SQLITE_IOCAP_ATOMIC8K 0x00000020
964#define SQLITE_IOCAP_ATOMIC16K 0x00000040
965#define SQLITE_IOCAP_ATOMIC32K 0x00000080
966#define SQLITE_IOCAP_ATOMIC64K 0x00000100
967#define SQLITE_IOCAP_SAFE_APPEND 0x00000200
968#define SQLITE_IOCAP_SEQUENTIAL 0x00000400
971#define SQLITE_IOCAP_IMMUTABLE 0x00002000
972#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000
975** CAPI3REF: File Locking Levels
977** SQLite uses one of these integer values as the second
978** argument to calls it makes to the xLock() and xUnlock() methods
979** of an [sqlite3_io_methods] object.
981#define SQLITE_LOCK_NONE 0
988** CAPI3REF: Synchronization Type Flags
990** When SQLite invokes the xSync() method of an
991** [sqlite3_io_methods] object it uses a combination of
992** these integer values as the second argument.
994** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
995** sync operation only needs to flush data to mass storage. Inode
996** information need not be flushed. If the lower four bits of the flag
997** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
998** If the lower four bits equal SQLITE_SYNC_FULL, that means
999** to use Mac OS X style fullsync instead of fsync().
1001** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
1002** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
1003** settings. The [synchronous pragma] determines when calls to the
1004** xSync VFS method occur and applies uniformly across all platforms.
1005** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
1006** energetic or rigorous or forceful the sync operations are and
1007** only make a difference on Mac OSX for the default SQLite code.
1008** (Third-party VFS implementations might also make the distinction
1009** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
1010** operating systems natively supported by SQLite, only Mac OSX
1011** cares about the difference.)
1013#define SQLITE_SYNC_NORMAL 0x00002
1014#define SQLITE_SYNC_FULL 0x00003
1015#define SQLITE_SYNC_DATAONLY 0x00010
1018** CAPI3REF: OS Interface Open File Handle
1020** An [sqlite3_file] object represents an open file in the
1021** [sqlite3_vfs | OS interface layer]. Individual OS interface
1022** implementations will
1023** want to subclass this object by appending additional fields
1024** for their own use. The pMethods entry is a pointer to an
1025** [sqlite3_io_methods] object that defines methods for performing
1026** I/O operations on the open file.
1028typedef struct sqlite3_file sqlite3_file;
1029struct sqlite3_file {
1030 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
1034** CAPI3REF: OS Interface File Virtual Methods Object
1036** Every file opened by the [sqlite3_vfs.xOpen] method populates an
1037** [sqlite3_file] object (or, more commonly, a subclass of the
1038** [sqlite3_file] object) with a pointer to an instance of this object.
1039** This object defines the methods used to perform various operations
1040** against the open file represented by the [sqlite3_file] object.
1042** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
1043** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
1044** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The
1045** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
1046** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
1047** to NULL.
1049** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
1050** [SQLITE_SYNC_FULL]. The first choice is the normal fsync().
1051** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY]
1052** flag may be ORed in to indicate that only the data of the file
1053** and not its inode needs to be synced.
1055** The integer values to xLock() and xUnlock() are one of
1056** <ul>
1057** <li> [SQLITE_LOCK_NONE],
1058** <li> [SQLITE_LOCK_SHARED],
1060** <li> [SQLITE_LOCK_PENDING], or
1062** </ul>
1063** xLock() increases the lock. xUnlock() decreases the lock.
1064** The xCheckReservedLock() method checks whether any database connection,
1065** either in this process or in some other process, is holding a RESERVED,
1066** PENDING, or EXCLUSIVE lock on the file. It returns true
1067** if such a lock exists and false otherwise.
1069** The xFileControl() method is a generic interface that allows custom
1070** VFS implementations to directly control an open file using the
1071** [sqlite3_file_control()] interface. The second "op" argument is an
1072** integer opcode. The third argument is a generic pointer intended to
1073** point to a structure that may contain arguments or space in which to
1074** write return values. Potential uses for xFileControl() might be
1075** functions to enable blocking locks with timeouts, to change the
1076** locking strategy (for example to use dot-file locks), to inquire
1077** about the status of a lock, or to break stale locks. The SQLite
1078** core reserves all opcodes less than 100 for its own use.
1079** A [file control opcodes | list of opcodes] less than 100 is available.
1080** Applications that define a custom xFileControl method should use opcodes
1081** greater than 100 to avoid conflicts. VFS implementations should
1082** return [SQLITE_NOTFOUND] for file control opcodes that they do not
1083** recognize.
1085** The xSectorSize() method returns the sector size of the
1086** device that underlies the file. The sector size is the
1087** minimum write that can be performed without disturbing
1088** other bytes in the file. The xDeviceCharacteristics()
1089** method returns a bit vector describing behaviors of the
1090** underlying device:
1092** <ul>
1094** <li> [SQLITE_IOCAP_ATOMIC512]
1099** <li> [SQLITE_IOCAP_ATOMIC16K]
1100** <li> [SQLITE_IOCAP_ATOMIC32K]
1101** <li> [SQLITE_IOCAP_ATOMIC64K]
1108** </ul>
1110** The SQLITE_IOCAP_ATOMIC property means that all writes of
1111** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
1112** mean that writes of blocks that are nnn bytes in size and
1113** are aligned to an address which is an integer multiple of
1114** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
1115** that when data is appended to a file, the data is appended
1116** first then the size of the file is extended, never the other
1117** way around. The SQLITE_IOCAP_SEQUENTIAL property means that
1118** information is written to disk in the same order as calls
1119** to xWrite().
1121** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
1122** in the unread portions of the buffer with zeros. A VFS that
1123** fails to zero-fill short reads might seem to work. However,
1124** failure to zero-fill short reads will eventually lead to
1125** database corruption.
1127typedef struct sqlite3_io_methods sqlite3_io_methods;
1128struct sqlite3_io_methods {
1129 int iVersion;
1130 int (*xClose)(sqlite3_file*);
1131 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
1132 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
1133 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
1134 int (*xSync)(sqlite3_file*, int flags);
1135 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
1136 int (*xLock)(sqlite3_file*, int);
1137 int (*xUnlock)(sqlite3_file*, int);
1138 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
1139 int (*xFileControl)(sqlite3_file*, int op, void *pArg);
1140 int (*xSectorSize)(sqlite3_file*);
1141 int (*xDeviceCharacteristics)(sqlite3_file*);
1142 /* Methods above are valid for version 1 */
1143 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
1144 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
1145 void (*xShmBarrier)(sqlite3_file*);
1146 int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
1147 /* Methods above are valid for version 2 */
1148 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
1149 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
1150 /* Methods above are valid for version 3 */
1151 /* Additional methods may be added in future releases */
1155** CAPI3REF: Standard File Control Opcodes
1156** KEYWORDS: {file control opcodes} {file control opcode}
1158** These integer constants are opcodes for the xFileControl method
1159** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
1160** interface.
1162** <ul>
1164** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This
1165** opcode causes the xFileControl method to write the current state of
1166** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
1168** into an integer that the pArg argument points to. This capability
1169** is used during testing and is only available when the SQLITE_TEST
1170** compile-time option is used.
1173** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
1174** layer a hint of how large the database file will grow to be during the
1175** current transaction. This hint is not guaranteed to be accurate but it
1176** is often close. The underlying VFS might choose to preallocate database
1177** file space based on this hint in order to help writes to the database
1178** file run faster.
1181** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that
1182** implements [sqlite3_deserialize()] to set an upper bound on the size
1183** of the in-memory database. The argument is a pointer to a [sqlite3_int64].
1184** If the integer pointed to is negative, then it is filled in with the
1185** current limit. Otherwise the limit is set to the larger of the value
1186** of the integer pointed to and the current database size. The integer
1187** pointed to is set to the new limit.
1190** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
1191** extends and truncates the database file in chunks of a size specified
1192** by the user. The fourth argument to [sqlite3_file_control()] should
1193** point to an integer (type int) containing the new chunk-size to use
1194** for the nominated database. Allocating database file space in large
1195** chunks (say 1MB at a time), may reduce file-system fragmentation and
1196** improve performance on some systems.
1199** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
1200** to the [sqlite3_file] object associated with a particular database
1201** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER].
1204** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
1205** to the [sqlite3_file] object associated with the journal file (either
1206** the [rollback journal] or the [write-ahead log]) for a particular database
1207** connection. See also [SQLITE_FCNTL_FILE_POINTER].
1210** No longer in use.
1212** <li>[[SQLITE_FCNTL_SYNC]]
1213** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
1214** sent to the VFS immediately before the xSync method is invoked on a
1215** database file descriptor. Or, if the xSync method is not invoked
1216** because the user has configured SQLite with
1217** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
1218** of the xSync method. In most cases, the pointer argument passed with
1219** this file-control is NULL. However, if the database file is being synced
1220** as part of a multi-database commit, the argument points to a nul-terminated
1221** string containing the transactions super-journal file name. VFSes that
1222** do not need this signal should silently ignore this opcode. Applications
1223** should not call [sqlite3_file_control()] with this opcode as doing so may
1224** disrupt the operation of the specialized VFSes that do require it.
1227** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
1228** and sent to the VFS after a transaction has been committed immediately
1229** but before the database is unlocked. VFSes that do not need this signal
1230** should silently ignore this opcode. Applications should not call
1231** [sqlite3_file_control()] with this opcode as doing so may disrupt the
1232** operation of the specialized VFSes that do require it.
1234** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
1235** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
1236** retry counts and intervals for certain disk I/O operations for the
1237** windows [VFS] in order to provide robustness in the presence of
1238** anti-virus programs. By default, the windows VFS will retry file read,
1239** file write, and file delete operations up to 10 times, with a delay
1240** of 25 milliseconds before the first retry and with the delay increasing
1241** by an additional 25 milliseconds with each subsequent retry. This
1242** opcode allows these two values (10 retries and 25 milliseconds of delay)
1243** to be adjusted. The values are changed for all database connections
1244** within the same process. The argument is a pointer to an array of two
1245** integers where the first integer is the new retry count and the second
1246** integer is the delay. If either integer is negative, then the setting
1247** is not changed but instead the prior value of that setting is written
1248** into the array entry, allowing the current retry settings to be
1249** interrogated. The zDbName parameter is ignored.
1252** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
1253** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary
1254** write ahead log ([WAL file]) and shared memory
1255** files used for transaction control
1256** are automatically deleted when the latest connection to the database
1257** closes. Setting persistent WAL mode causes those files to persist after
1258** close. Persisting the files is useful when other processes that do not
1259** have write permission on the directory containing the database file want
1260** to read the database file, as the WAL and shared memory files must exist
1261** in order for the database to be readable. The fourth parameter to
1262** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
1263** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
1264** WAL mode. If the integer is -1, then it is overwritten with the current
1265** WAL persistence setting.
1268** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
1269** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
1270** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
1271** xDeviceCharacteristics methods. The fourth parameter to
1272** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
1273** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
1274** mode. If the integer is -1, then it is overwritten with the current
1275** zero-damage mode setting.
1278** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
1279** a write transaction to indicate that, unless it is rolled back for some
1280** reason, the entire database file will be overwritten by the current
1281** transaction. This is used by VACUUM operations.
1284** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
1285** all [VFSes] in the VFS stack. The names are of all VFS shims and the
1286** final bottom-level VFS are written into memory obtained from
1287** [sqlite3_malloc()] and the result is stored in the char* variable
1288** that the fourth parameter of [sqlite3_file_control()] points to.
1289** The caller is responsible for freeing the memory when done. As with
1290** all file-control actions, there is no guarantee that this will actually
1291** do anything. Callers should initialize the char* variable to a NULL
1292** pointer in case this file-control is not implemented. This file-control
1293** is intended for diagnostic use only.
1296** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
1297** [VFSes] currently in use. ^(The argument X in
1298** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
1299** of type "[sqlite3_vfs] **". This opcodes will set *X
1300** to a pointer to the top-level VFS.)^
1301** ^When there are multiple VFS shims in the stack, this opcode finds the
1302** upper-most shim only.
1304** <li>[[SQLITE_FCNTL_PRAGMA]]
1305** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
1306** file control is sent to the open [sqlite3_file] object corresponding
1307** to the database file to which the pragma statement refers. ^The argument
1308** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
1309** pointers to strings (char**) in which the second element of the array
1310** is the name of the pragma and the third element is the argument to the
1311** pragma or NULL if the pragma has no argument. ^The handler for an
1312** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
1313** of the char** argument point to a string obtained from [sqlite3_mprintf()]
1314** or the equivalent and that string will become the result of the pragma or
1315** the error message if the pragma fails. ^If the
1316** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
1317** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA]
1318** file control returns [SQLITE_OK], then the parser assumes that the
1319** VFS has handled the PRAGMA itself and the parser generates a no-op
1320** prepared statement if result string is NULL, or that returns a copy
1321** of the result string if the string is non-NULL.
1322** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
1323** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
1324** that the VFS encountered an error while handling the [PRAGMA] and the
1325** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA]
1326** file control occurs at the beginning of pragma statement analysis and so
1327** it is able to override built-in [PRAGMA] statements.
1331** file-control may be invoked by SQLite on the database file handle
1332** shortly after it is opened in order to provide a custom VFS with access
1333** to the connection's busy-handler callback. The argument is of type (void**)
1334** - an array of two (void *) values. The first (void *) actually points
1335** to a function of type (int (*)(void *)). In order to invoke the connection's
1336** busy-handler, this function should be invoked with the second (void *) in
1337** the array as the only argument. If it returns non-zero, then the operation
1338** should be retried. If it returns zero, the custom VFS should abandon the
1339** current operation.
1342** ^Applications can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
1343** to have SQLite generate a
1344** temporary filename using the same algorithm that is followed to generate
1345** temporary filenames for TEMP tables and other internal uses. The
1346** argument should be a char** which will be filled with the filename
1347** written into memory obtained from [sqlite3_malloc()]. The caller should
1348** invoke [sqlite3_free()] on the result to avoid a memory leak.
1351** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
1352** maximum number of bytes that will be used for memory-mapped I/O.
1353** The argument is a pointer to a value of type sqlite3_int64 that
1354** is an advisory maximum number of bytes in the file to memory map. The
1355** pointer is overwritten with the old value. The limit is not changed if
1356** the value originally pointed to is negative, and so the current limit
1357** can be queried by passing in a pointer to a negative number. This
1358** file-control is used internally to implement [PRAGMA mmap_size].
1360** <li>[[SQLITE_FCNTL_TRACE]]
1361** The [SQLITE_FCNTL_TRACE] file control provides advisory information
1362** to the VFS about what the higher layers of the SQLite stack are doing.
1363** This file control is used by some VFS activity tracing [shims].
1364** The argument is a zero-terminated string. Higher layers in the
1365** SQLite stack may generate instances of this file control if
1366** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
1369** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
1370** pointer to an integer and it writes a boolean into that integer depending
1371** on whether or not the file has been renamed, moved, or deleted since it
1372** was first opened.
1375** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
1376** underlying native file handle associated with a file handle. This file
1377** control interprets its argument as a pointer to a native file handle and
1378** writes the resulting value there.
1381** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This
1382** opcode causes the xFileControl method to swap the file handle with the one
1383** pointed to by the pArg argument. This capability is used during testing
1384** and only needs to be supported when SQLITE_TEST is defined.
1387** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
1388** be advantageous to block on the next WAL lock if the lock is not immediately
1389** available. The WAL subsystem issues this signal during rare
1390** circumstances in order to fix a problem with priority inversion.
1391** Applications should <em>not</em> use this file-control.
1393** <li>[[SQLITE_FCNTL_ZIPVFS]]
1394** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
1395** VFS should return SQLITE_NOTFOUND for this opcode.
1397** <li>[[SQLITE_FCNTL_RBU]]
1398** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
1399** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for
1400** this opcode.
1403** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
1404** the file descriptor is placed in "batch write mode", which
1405** means all subsequent write operations will be deferred and done
1406** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems
1407** that do not support batch atomic writes will return SQLITE_NOTFOUND.
1408** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
1409** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
1411** no VFS interface calls on the same [sqlite3_file] file descriptor
1412** except for calls to the xWrite method and the xFileControl method
1416** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
1417** operations since the previous successful call to
1418** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
1419** This file control returns [SQLITE_OK] if and only if the writes were
1420** all performed successfully and have been committed to persistent storage.
1421** ^Regardless of whether or not it is successful, this file control takes
1422** the file descriptor out of batch write mode so that all subsequent
1423** write operations are independent.
1424** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
1425** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1428** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
1429** operations since the previous successful call to
1430** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
1431** ^This file control takes the file descriptor out of batch write mode
1432** so that all subsequent write operations are independent.
1433** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
1434** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
1437** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS
1438** to block for up to M milliseconds before failing when attempting to
1439** obtain a file lock using the xLock or xShmLock methods of the VFS.
1440** The parameter is a pointer to a 32-bit signed integer that contains
1441** the value that M is to be set to. Before returning, the 32-bit signed
1442** integer is overwritten with the previous value of M.
1445** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to
1446** a database file. The argument is a pointer to a 32-bit unsigned integer.
1447** The "data version" for the pager is written into the pointer. The
1448** "data version" changes whenever any change occurs to the corresponding
1449** database file, either through SQL statements on the same database
1450** connection or through transactions committed by separate database
1451** connections possibly in other processes. The [sqlite3_total_changes()]
1452** interface can be used to find if any database on the connection has changed,
1453** but that interface responds to changes on TEMP as well as MAIN and does
1454** not provide a mechanism to detect changes to MAIN only. Also, the
1455** [sqlite3_total_changes()] interface responds to internal changes only and
1456** omits changes made by other database connections. The
1457** [PRAGMA data_version] command provides a mechanism to detect changes to
1458** a single attached database that occur due to other database connections,
1459** but omits changes implemented by the database connection on which it is
1460** called. This file control is the only mechanism to detect changes that
1461** happen either internally or externally and that are associated with
1462** a particular attached database.
1465** The [SQLITE_FCNTL_CKPT_START] opcode is invoked from within a checkpoint
1466** in wal mode before the client starts to copy pages from the wal
1467** file to the database file.
1470** The [SQLITE_FCNTL_CKPT_DONE] opcode is invoked from within a checkpoint
1471** in wal mode after the client has finished copying pages from the wal
1472** file to the database file, but before the *-shm file is updated to
1473** record the fact that the pages have been checkpointed.
1474** </ul>
1477** The EXPERIMENTAL [SQLITE_FCNTL_EXTERNAL_READER] opcode is used to detect
1478** whether or not there is a database client in another process with a wal-mode
1479** transaction open on the database or not. It is only available on unix.The
1480** (void*) argument passed with this file-control should be a pointer to a
1481** value of type (int). The integer value is set to 1 if the database is a wal
1482** mode database and there exists at least one client in another process that
1483** currently has an SQL transaction open on the database. It is set to 0 if
1484** the database is not a wal-mode db, or if there is no such connection in any
1485** other process. This opcode cannot be used to detect transactions opened
1486** by clients within the current process, only within other processes.
1487** </ul>
1490** Used by the cksmvfs VFS module only.
1491** </ul>
1506#define SQLITE_FCNTL_PRAGMA 14
1510#define SQLITE_FCNTL_TRACE 19
1512#define SQLITE_FCNTL_SYNC 21
1516#define SQLITE_FCNTL_ZIPVFS 25
1517#define SQLITE_FCNTL_RBU 26
1521#define SQLITE_FCNTL_PDB 30
1534/* deprecated names */
1541** CAPI3REF: Mutex Handle
1543** The mutex module within SQLite defines [sqlite3_mutex] to be an
1544** abstract type for a mutex object. The SQLite core never looks
1545** at the internal representation of an [sqlite3_mutex]. It only
1546** deals with pointers to the [sqlite3_mutex] object.
1548** Mutexes are created using [sqlite3_mutex_alloc()].
1550typedef struct sqlite3_mutex sqlite3_mutex;
1553** CAPI3REF: Loadable Extension Thunk
1555** A pointer to the opaque sqlite3_api_routines structure is passed as
1556** the third parameter to entry points of [loadable extensions]. This
1557** structure must be typedefed in order to work around compiler warnings
1558** on some platforms.
1560typedef struct sqlite3_api_routines sqlite3_api_routines;
1563** CAPI3REF: OS Interface Object
1565** An instance of the sqlite3_vfs object defines the interface between
1566** the SQLite core and the underlying operating system. The "vfs"
1567** in the name of the object stands for "virtual file system". See
1568** the [VFS | VFS documentation] for further information.
1570** The VFS interface is sometimes extended by adding new methods onto
1571** the end. Each time such an extension occurs, the iVersion field
1572** is incremented. The iVersion value started out as 1 in
1573** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
1574** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
1575** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields
1576** may be appended to the sqlite3_vfs object and the iVersion value
1577** may increase again in future versions of SQLite.
1578** Note that due to an oversight, the structure
1579** of the sqlite3_vfs object changed in the transition from
1580** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
1581** and yet the iVersion field was not increased.
1583** The szOsFile field is the size of the subclassed [sqlite3_file]
1584** structure used by this VFS. mxPathname is the maximum length of
1585** a pathname in this VFS.
1587** Registered sqlite3_vfs objects are kept on a linked list formed by
1588** the pNext pointer. The [sqlite3_vfs_register()]
1589** and [sqlite3_vfs_unregister()] interfaces manage this list
1590** in a thread-safe way. The [sqlite3_vfs_find()] interface
1591** searches the list. Neither the application code nor the VFS
1592** implementation should use the pNext pointer.
1594** The pNext field is the only field in the sqlite3_vfs
1595** structure that SQLite will ever modify. SQLite will only access
1596** or modify this field while holding a particular static mutex.
1597** The application should never modify anything within the sqlite3_vfs
1598** object once the object has been registered.
1600** The zName field holds the name of the VFS module. The name must
1601** be unique across all VFS modules.
1603** [[sqlite3_vfs.xOpen]]
1604** ^SQLite guarantees that the zFilename parameter to xOpen
1605** is either a NULL pointer or string obtained
1606** from xFullPathname() with an optional suffix added.
1607** ^If a suffix is added to the zFilename parameter, it will
1608** consist of a single "-" character followed by no more than
1609** 11 alphanumeric and/or "-" characters.
1610** ^SQLite further guarantees that
1611** the string will be valid and unchanged until xClose() is
1612** called. Because of the previous sentence,
1613** the [sqlite3_file] can safely store a pointer to the
1614** filename if it needs to remember the filename for some reason.
1615** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1616** must invent its own temporary name for the file. ^Whenever the
1617** xFilename parameter is NULL it will also be the case that the
1618** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1620** The flags argument to xOpen() includes all bits set in
1621** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()]
1622** or [sqlite3_open16()] is used, then flags includes at least
1624** If xOpen() opens a file read-only then it sets *pOutFlags to
1625** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set.
1627** ^(SQLite will also add one of the following flags to the xOpen()
1628** call, depending on the object being opened:
1630** <ul>
1631** <li> [SQLITE_OPEN_MAIN_DB]
1633** <li> [SQLITE_OPEN_TEMP_DB]
1638** <li> [SQLITE_OPEN_WAL]
1639** </ul>)^
1641** The file I/O implementation can use the object type flags to
1642** change the way it deals with files. For example, an application
1643** that does not care about crash recovery or rollback might make
1644** the open of a journal file a no-op. Writes to this journal would
1645** also be no-ops, and any attempt to read the journal would return
1646** SQLITE_IOERR. Or the implementation might recognize that a database
1647** file will be doing page-aligned sector reads and writes in a random
1648** order and set up its I/O subsystem accordingly.
1650** SQLite might also add one of the following flags to the xOpen method:
1652** <ul>
1655** </ul>
1657** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1658** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE]
1659** will be set for TEMP databases and their journals, transient
1660** databases, and subjournals.
1662** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1663** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1664** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1665** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1666** SQLITE_OPEN_CREATE, is used to indicate that file should always
1667** be created, and that it is an error if it already exists.
1668** It is <i>not</i> used to indicate the file should be opened
1669** for exclusive access.
1671** ^At least szOsFile bytes of memory are allocated by SQLite
1672** to hold the [sqlite3_file] structure passed as the third
1673** argument to xOpen. The xOpen method does not have to
1674** allocate the structure; it should just fill it in. Note that
1675** the xOpen method must set the sqlite3_file.pMethods to either
1676** a valid [sqlite3_io_methods] object or to NULL. xOpen must do
1677** this even if the open fails. SQLite expects that the sqlite3_file.pMethods
1678** element will be valid after xOpen returns regardless of the success
1679** or failure of the xOpen call.
1681** [[sqlite3_vfs.xAccess]]
1682** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1683** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1684** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1685** to test whether a file is at least readable. The SQLITE_ACCESS_READ
1686** flag is never actually used and is not implemented in the built-in
1687** VFSes of SQLite. The file is named by the second argument and can be a
1688** directory. The xAccess method returns [SQLITE_OK] on success or some
1689** non-zero error code if there is an I/O error or if the name of
1690** the file given in the second argument is illegal. If SQLITE_OK
1691** is returned, then non-zero or zero is written into *pResOut to indicate
1692** whether or not the file is accessible.
1694** ^SQLite will always allocate at least mxPathname+1 bytes for the
1695** output buffer xFullPathname. The exact size of the output buffer
1696** is also passed as a parameter to both methods. If the output buffer
1697** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1698** handled as a fatal error by SQLite, vfs implementations should endeavor
1699** to prevent this by setting mxPathname to a sufficiently large value.
1701** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1702** interfaces are not strictly a part of the filesystem, but they are
1703** included in the VFS structure for completeness.
1704** The xRandomness() function attempts to return nBytes bytes
1705** of good-quality randomness into zOut. The return value is
1706** the actual number of bytes of randomness obtained.
1707** The xSleep() method causes the calling thread to sleep for at
1708** least the number of microseconds given. ^The xCurrentTime()
1709** method returns a Julian Day Number for the current date and time as
1710** a floating point value.
1711** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1712** Day Number multiplied by 86400000 (the number of milliseconds in
1713** a 24-hour day).
1714** ^SQLite will use the xCurrentTimeInt64() method to get the current
1715** date and time if that method is available (if iVersion is 2 or
1716** greater and the function pointer is not NULL) and will fall back
1717** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1719** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1720** are not used by the SQLite core. These optional interfaces are provided
1721** by some VFSes to facilitate testing of the VFS code. By overriding
1722** system calls with functions under its control, a test program can
1723** simulate faults and error conditions that would otherwise be difficult
1724** or impossible to induce. The set of system calls that can be overridden
1725** varies from one VFS to another, and from one version of the same VFS to the
1726** next. Applications that use these interfaces must be prepared for any
1727** or all of these interfaces to be NULL or for their behavior to change
1728** from one release to the next. Applications must not attempt to access
1729** any of these methods if the iVersion of the VFS is less than 3.
1731typedef struct sqlite3_vfs sqlite3_vfs;
1732typedef void (*sqlite3_syscall_ptr)(void);
1733struct sqlite3_vfs {
1734 int iVersion; /* Structure version number (currently 3) */
1735 int szOsFile; /* Size of subclassed sqlite3_file */
1736 int mxPathname; /* Maximum file pathname length */
1737 sqlite3_vfs *pNext; /* Next registered VFS */
1738 const char *zName; /* Name of this virtual file system */
1739 void *pAppData; /* Pointer to application-specific data */
1740 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1741 int flags, int *pOutFlags);
1742 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1743 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1744 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1745 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1746 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1747 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1748 void (*xDlClose)(sqlite3_vfs*, void*);
1749 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1750 int (*xSleep)(sqlite3_vfs*, int microseconds);
1751 int (*xCurrentTime)(sqlite3_vfs*, double*);
1752 int (*xGetLastError)(sqlite3_vfs*, int, char *);
1753 /*
1754 ** The methods above are in version 1 of the sqlite_vfs object
1755 ** definition. Those that follow are added in version 2 or later
1756 */
1757 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1758 /*
1759 ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1760 ** Those below are for version 3 and greater.
1761 */
1762 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1763 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1764 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1765 /*
1766 ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1767 ** New fields may be appended in future versions. The iVersion
1768 ** value will increment whenever this happens.
1769 */
1773** CAPI3REF: Flags for the xAccess VFS method
1775** These integer constants can be used as the third parameter to
1776** the xAccess method of an [sqlite3_vfs] object. They determine
1777** what kind of permissions the xAccess method is looking for.
1778** With SQLITE_ACCESS_EXISTS, the xAccess method
1779** simply checks whether the file exists.
1780** With SQLITE_ACCESS_READWRITE, the xAccess method
1781** checks whether the named directory is both readable and writable
1782** (in other words, if files can be added, removed, and renamed within
1783** the directory).
1784** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1785** [temp_store_directory pragma], though this could change in a future
1786** release of SQLite.
1787** With SQLITE_ACCESS_READ, the xAccess method
1788** checks whether the file is readable. The SQLITE_ACCESS_READ constant is
1789** currently unused, though it might be used in a future release of
1790** SQLite.
1793#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
1794#define SQLITE_ACCESS_READ 2 /* Unused */
1797** CAPI3REF: Flags for the xShmLock VFS method
1799** These integer constants define the various locking operations
1800** allowed by the xShmLock method of [sqlite3_io_methods]. The
1801** following are the only legal combinations of flags to the
1802** xShmLock method:
1804** <ul>
1809** </ul>
1811** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1812** was given on the corresponding lock.
1814** The xShmLock method can transition between unlocked and SHARED or
1815** between unlocked and EXCLUSIVE. It cannot transition between SHARED
1816** and EXCLUSIVE.
1818#define SQLITE_SHM_UNLOCK 1
1819#define SQLITE_SHM_LOCK 2
1820#define SQLITE_SHM_SHARED 4
1824** CAPI3REF: Maximum xShmLock index
1826** The xShmLock method on [sqlite3_io_methods] may use values
1827** between 0 and this upper bound as its "offset" argument.
1828** The SQLite core will never attempt to acquire or release a
1829** lock outside of this range
1831#define SQLITE_SHM_NLOCK 8
1835** CAPI3REF: Initialize The SQLite Library
1837** ^The sqlite3_initialize() routine initializes the
1838** SQLite library. ^The sqlite3_shutdown() routine
1839** deallocates any resources that were allocated by sqlite3_initialize().
1840** These routines are designed to aid in process initialization and
1841** shutdown on embedded systems. Workstation applications using
1842** SQLite normally do not need to invoke either of these routines.
1844** A call to sqlite3_initialize() is an "effective" call if it is
1845** the first time sqlite3_initialize() is invoked during the lifetime of
1846** the process, or if it is the first time sqlite3_initialize() is invoked
1847** following a call to sqlite3_shutdown(). ^(Only an effective call
1848** of sqlite3_initialize() does any initialization. All other calls
1849** are harmless no-ops.)^
1851** A call to sqlite3_shutdown() is an "effective" call if it is the first
1852** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only
1853** an effective call to sqlite3_shutdown() does any deinitialization.
1854** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1856** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1857** is not. The sqlite3_shutdown() interface must only be called from a
1858** single thread. All open [database connections] must be closed and all
1859** other SQLite resources must be deallocated prior to invoking
1860** sqlite3_shutdown().
1862** Among other things, ^sqlite3_initialize() will invoke
1863** sqlite3_os_init(). Similarly, ^sqlite3_shutdown()
1864** will invoke sqlite3_os_end().
1866** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1867** ^If for some reason, sqlite3_initialize() is unable to initialize
1868** the library (perhaps it is unable to allocate a needed resource such
1869** as a mutex) it returns an [error code] other than [SQLITE_OK].
1871** ^The sqlite3_initialize() routine is called internally by many other
1872** SQLite interfaces so that an application usually does not need to
1873** invoke sqlite3_initialize() directly. For example, [sqlite3_open()]
1874** calls sqlite3_initialize() so the SQLite library will be automatically
1875** initialized when [sqlite3_open()] is called if it has not be initialized
1876** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1877** compile-time option, then the automatic calls to sqlite3_initialize()
1878** are omitted and the application must call sqlite3_initialize() directly
1879** prior to using any other SQLite interface. For maximum portability,
1880** it is recommended that applications always invoke sqlite3_initialize()
1881** directly prior to using any other SQLite interface. Future releases
1882** of SQLite may require this. In other words, the behavior exhibited
1883** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1884** default behavior in some future release of SQLite.
1886** The sqlite3_os_init() routine does operating-system specific
1887** initialization of the SQLite library. The sqlite3_os_end()
1888** routine undoes the effect of sqlite3_os_init(). Typical tasks
1889** performed by these routines include allocation or deallocation
1890** of static resources, initialization of global variables,
1891** setting up a default [sqlite3_vfs] module, or setting up
1892** a default configuration using [sqlite3_config()].
1894** The application should never invoke either sqlite3_os_init()
1895** or sqlite3_os_end() directly. The application should only invoke
1896** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
1897** interface is called automatically by sqlite3_initialize() and
1898** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
1899** implementations for sqlite3_os_init() and sqlite3_os_end()
1900** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1901** When [custom builds | built for other platforms]
1902** (using the [SQLITE_OS_OTHER=1] compile-time
1903** option) the application must supply a suitable implementation for
1904** sqlite3_os_init() and sqlite3_os_end(). An application-supplied
1905** implementation of sqlite3_os_init() or sqlite3_os_end()
1906** must return [SQLITE_OK] on success and some other [error code] upon
1907** failure.
1909SQLITE_API int sqlite3_initialize(void);
1910SQLITE_API int sqlite3_shutdown(void);
1911SQLITE_API int sqlite3_os_init(void);
1912SQLITE_API int sqlite3_os_end(void);
1915** CAPI3REF: Configuring The SQLite Library
1917** The sqlite3_config() interface is used to make global configuration
1918** changes to SQLite in order to tune SQLite to the specific needs of
1919** the application. The default configuration is recommended for most
1920** applications and so this routine is usually not necessary. It is
1921** provided to support rare applications with unusual needs.
1923** <b>The sqlite3_config() interface is not threadsafe. The application
1924** must ensure that no other SQLite interfaces are invoked by other
1925** threads while sqlite3_config() is running.</b>
1927** The sqlite3_config() interface
1928** may only be invoked prior to library initialization using
1929** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1930** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1931** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1932** Note, however, that ^sqlite3_config() can be called as part of the
1933** implementation of an application-defined [sqlite3_os_init()].
1935** The first argument to sqlite3_config() is an integer
1936** [configuration option] that determines
1937** what property of SQLite is to be configured. Subsequent arguments
1938** vary depending on the [configuration option]
1939** in the first argument.
1941** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1942** ^If the option is unknown or SQLite is unable to set the option
1943** then this routine returns a non-zero [error code].
1945SQLITE_API int sqlite3_config(int, ...);
1948** CAPI3REF: Configure database connections
1949** METHOD: sqlite3
1951** The sqlite3_db_config() interface is used to make configuration
1952** changes to a [database connection]. The interface is similar to
1953** [sqlite3_config()] except that the changes apply to a single
1954** [database connection] (specified in the first argument).
1956** The second argument to sqlite3_db_config(D,V,...) is the
1957** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1958** that indicates what aspect of the [database connection] is being configured.
1959** Subsequent arguments vary depending on the configuration verb.
1961** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1962** the call is considered successful.
1964SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
1967** CAPI3REF: Memory Allocation Routines
1969** An instance of this object defines the interface between SQLite
1970** and low-level memory allocation routines.
1972** This object is used in only one place in the SQLite interface.
1973** A pointer to an instance of this object is the argument to
1974** [sqlite3_config()] when the configuration option is
1976** By creating an instance of this object
1977** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1978** during configuration, an application can specify an alternative
1979** memory allocation subsystem for SQLite to use for all of its
1980** dynamic memory needs.
1982** Note that SQLite comes with several [built-in memory allocators]
1983** that are perfectly adequate for the overwhelming majority of applications
1984** and that this object is only useful to a tiny minority of applications
1985** with specialized memory allocation requirements. This object is
1986** also used during testing of SQLite in order to specify an alternative
1987** memory allocator that simulates memory out-of-memory conditions in
1988** order to verify that SQLite recovers gracefully from such
1989** conditions.
1991** The xMalloc, xRealloc, and xFree methods must work like the
1992** malloc(), realloc() and free() functions from the standard C library.
1993** ^SQLite guarantees that the second argument to
1994** xRealloc is always a value returned by a prior call to xRoundup.
1996** xSize should return the allocated size of a memory allocation
1997** previously obtained from xMalloc or xRealloc. The allocated size
1998** is always at least as big as the requested size but may be larger.
2000** The xRoundup method returns what would be the allocated size of
2001** a memory allocation given a particular requested size. Most memory
2002** allocators round up memory allocations at least to the next multiple
2003** of 8. Some allocators round up to a larger multiple or to a power of 2.
2004** Every memory allocation request coming in through [sqlite3_malloc()]
2005** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0,
2006** that causes the corresponding memory allocation to fail.
2008** The xInit method initializes the memory allocator. For example,
2009** it might allocate any required mutexes or initialize internal data
2010** structures. The xShutdown method is invoked (indirectly) by
2011** [sqlite3_shutdown()] and should deallocate any resources acquired
2012** by xInit. The pAppData pointer is used as the only parameter to
2013** xInit and xShutdown.
2015** SQLite holds the [SQLITE_MUTEX_STATIC_MAIN] mutex when it invokes
2016** the xInit method, so the xInit method need not be threadsafe. The
2017** xShutdown method is only called from [sqlite3_shutdown()] so it does
2018** not need to be threadsafe either. For all other methods, SQLite
2019** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
2020** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
2021** it is by default) and so the methods are automatically serialized.
2022** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
2023** methods must be threadsafe or else make their own arrangements for
2024** serialization.
2026** SQLite will never invoke xInit() more than once without an intervening
2027** call to xShutdown().
2029typedef struct sqlite3_mem_methods sqlite3_mem_methods;
2030struct sqlite3_mem_methods {
2031 void *(*xMalloc)(int); /* Memory allocation function */
2032 void (*xFree)(void*); /* Free a prior allocation */
2033 void *(*xRealloc)(void*,int); /* Resize an allocation */
2034 int (*xSize)(void*); /* Return the size of an allocation */
2035 int (*xRoundup)(int); /* Round up request size to allocation size */
2036 int (*xInit)(void*); /* Initialize the memory allocator */
2037 void (*xShutdown)(void*); /* Deinitialize the memory allocator */
2038 void *pAppData; /* Argument to xInit() and xShutdown() */
2042** CAPI3REF: Configuration Options
2043** KEYWORDS: {configuration option}
2045** These constants are the available integer configuration options that
2046** can be passed as the first argument to the [sqlite3_config()] interface.
2048** New configuration options may be added in future releases of SQLite.
2049** Existing configuration options might be discontinued. Applications
2050** should check the return code from [sqlite3_config()] to make sure that
2051** the call worked. The [sqlite3_config()] interface will return a
2052** non-zero [error code] if a discontinued or unsupported configuration option
2053** is invoked.
2055** <dl>
2057** <dd>There are no arguments to this option. ^This option sets the
2058** [threading mode] to Single-thread. In other words, it disables
2059** all mutexing and puts SQLite into a mode where it can only be used
2060** by a single thread. ^If SQLite is compiled with
2061** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
2062** it is not possible to change the [threading mode] from its default
2063** value of Single-thread and so [sqlite3_config()] will return
2065** configuration option.</dd>
2068** <dd>There are no arguments to this option. ^This option sets the
2069** [threading mode] to Multi-thread. In other words, it disables
2070** mutexing on [database connection] and [prepared statement] objects.
2071** The application is responsible for serializing access to
2072** [database connections] and [prepared statements]. But other mutexes
2073** are enabled so that SQLite will be safe to use in a multi-threaded
2074** environment as long as no two threads attempt to use the same
2075** [database connection] at the same time. ^If SQLite is compiled with
2076** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
2077** it is not possible to set the Multi-thread [threading mode] and
2078** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
2079** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
2082** <dd>There are no arguments to this option. ^This option sets the
2083** [threading mode] to Serialized. In other words, this option enables
2084** all mutexes including the recursive
2085** mutexes on [database connection] and [prepared statement] objects.
2086** In this mode (which is the default when SQLite is compiled with
2087** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
2088** to [database connections] and [prepared statements] so that the
2089** application is free to use the same [database connection] or the
2090** same [prepared statement] in different threads at the same time.
2091** ^If SQLite is compiled with
2092** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
2093** it is not possible to set the Serialized [threading mode] and
2094** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
2095** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
2098** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
2099** a pointer to an instance of the [sqlite3_mem_methods] structure.
2100** The argument specifies
2101** alternative low-level memory allocation routines to be used in place of
2102** the memory allocation routines built into SQLite.)^ ^SQLite makes
2103** its own private copy of the content of the [sqlite3_mem_methods] structure
2104** before the [sqlite3_config()] call returns.</dd>
2107** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
2108** is a pointer to an instance of the [sqlite3_mem_methods] structure.
2109** The [sqlite3_mem_methods]
2110** structure is filled with the currently defined memory allocation routines.)^
2111** This option can be used to overload the default memory allocation
2112** routines with a wrapper that simulations memory allocation failure or
2113** tracks memory usage, for example. </dd>
2116** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
2117** type int, interpreted as a boolean, which if true provides a hint to
2118** SQLite that it should avoid large memory allocations if possible.
2119** SQLite will run faster if it is free to make large memory allocations,
2120** but some application might prefer to run slower in exchange for
2121** guarantees about memory fragmentation that are possible if large
2122** allocations are avoided. This hint is normally off.
2123** </dd>
2126** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
2127** interpreted as a boolean, which enables or disables the collection of
2128** memory allocation statistics. ^(When memory allocation statistics are
2129** disabled, the following SQLite interfaces become non-operational:
2130** <ul>
2131** <li> [sqlite3_hard_heap_limit64()]
2132** <li> [sqlite3_memory_used()]
2133** <li> [sqlite3_memory_highwater()]
2134** <li> [sqlite3_soft_heap_limit64()]
2135** <li> [sqlite3_status64()]
2136** </ul>)^
2137** ^Memory allocation statistics are enabled by default unless SQLite is
2138** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
2139** allocation statistics are disabled by default.
2140** </dd>
2143** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
2144** </dd>
2147** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
2148** that SQLite can use for the database page cache with the default page
2149** cache implementation.
2150** This configuration option is a no-op if an application-defined page
2151** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
2152** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
2153** 8-byte aligned memory (pMem), the size of each page cache line (sz),
2154** and the number of cache lines (N).
2155** The sz argument should be the size of the largest database page
2156** (a power of two between 512 and 65536) plus some extra bytes for each
2157** page header. ^The number of extra bytes needed by the page header
2158** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
2159** ^It is harmless, apart from the wasted memory,
2160** for the sz parameter to be larger than necessary. The pMem
2161** argument must be either a NULL pointer or a pointer to an 8-byte
2162** aligned block of memory of at least sz*N bytes, otherwise
2163** subsequent behavior is undefined.
2164** ^When pMem is not NULL, SQLite will strive to use the memory provided
2165** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
2166** a page cache line is larger than sz bytes or if all of the pMem buffer
2167** is exhausted.
2168** ^If pMem is NULL and N is non-zero, then each database connection
2169** does an initial bulk allocation for page cache memory
2170** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
2171** of -1024*N bytes if N is negative, . ^If additional
2172** page cache memory is needed beyond what is provided by the initial
2173** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
2174** additional cache line. </dd>
2177** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
2178** that SQLite will use for all of its dynamic memory allocation needs
2179** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
2180** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
2181** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
2182** [SQLITE_ERROR] if invoked otherwise.
2183** ^There are three arguments to SQLITE_CONFIG_HEAP:
2184** An 8-byte aligned pointer to the memory,
2185** the number of bytes in the memory buffer, and the minimum allocation size.
2186** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
2187** to using its default memory allocator (the system malloc() implementation),
2188** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the
2189** memory pointer is not NULL then the alternative memory
2190** allocator is engaged to handle all of SQLites memory allocation needs.
2191** The first pointer (the memory pointer) must be aligned to an 8-byte
2192** boundary or subsequent behavior of SQLite will be undefined.
2193** The minimum allocation size is capped at 2**12. Reasonable values
2194** for the minimum allocation size are 2**5 through 2**8.</dd>
2197** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
2198** pointer to an instance of the [sqlite3_mutex_methods] structure.
2199** The argument specifies alternative low-level mutex routines to be used
2200** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of
2201** the content of the [sqlite3_mutex_methods] structure before the call to
2202** [sqlite3_config()] returns. ^If SQLite is compiled with
2203** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
2204** the entire mutexing subsystem is omitted from the build and hence calls to
2205** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
2206** return [SQLITE_ERROR].</dd>
2209** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
2210** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The
2211** [sqlite3_mutex_methods]
2212** structure is filled with the currently defined mutex routines.)^
2213** This option can be used to overload the default mutex allocation
2214** routines with a wrapper used to track mutex usage for performance
2215** profiling or testing, for example. ^If SQLite is compiled with
2216** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
2217** the entire mutexing subsystem is omitted from the build and hence calls to
2218** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
2219** return [SQLITE_ERROR].</dd>
2222** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
2223** the default size of lookaside memory on each [database connection].
2224** The first argument is the
2225** size of each lookaside buffer slot and the second is the number of
2226** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE
2227** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
2228** option to [sqlite3_db_config()] can be used to change the lookaside
2229** configuration on individual connections.)^ </dd>
2232** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
2233** a pointer to an [sqlite3_pcache_methods2] object. This object specifies
2234** the interface to a custom page cache implementation.)^
2235** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
2238** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
2239** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of
2240** the current page cache implementation into that object.)^ </dd>
2243** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
2244** global [error log].
2245** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
2246** function with a call signature of void(*)(void*,int,const char*),
2247** and a pointer to void. ^If the function pointer is not NULL, it is
2248** invoked by [sqlite3_log()] to process each logging event. ^If the
2249** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
2250** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
2251** passed through as the first parameter to the application-defined logger
2252** function whenever that function is invoked. ^The second parameter to
2253** the logger function is a copy of the first parameter to the corresponding
2254** [sqlite3_log()] call and is intended to be a [result code] or an
2255** [extended result code]. ^The third parameter passed to the logger is
2256** log message after formatting via [sqlite3_snprintf()].
2257** The SQLite logging interface is not reentrant; the logger function
2258** supplied by the application must not invoke any SQLite interface.
2259** In a multi-threaded application, the application-defined logger
2260** function must be threadsafe. </dd>
2263** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
2264** If non-zero, then URI handling is globally enabled. If the parameter is zero,
2265** then URI handling is globally disabled.)^ ^If URI handling is globally
2266** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
2267** [sqlite3_open16()] or
2268** specified as part of [ATTACH] commands are interpreted as URIs, regardless
2269** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
2270** connection is opened. ^If it is globally disabled, filenames are
2271** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
2272** database connection is opened. ^(By default, URI handling is globally
2273** disabled. The default value may be changed by compiling with the
2274** [SQLITE_USE_URI] symbol defined.)^
2277** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
2278** argument which is interpreted as a boolean in order to enable or disable
2279** the use of covering indices for full table scans in the query optimizer.
2280** ^The default setting is determined
2281** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
2282** if that compile-time option is omitted.
2283** The ability to disable the use of covering indices for full table scans
2284** is because some incorrectly coded legacy applications might malfunction
2285** when the optimization is enabled. Providing the ability to
2286** disable the optimization allows the older, buggy application code to work
2287** without change even with newer versions of SQLite.
2291** <dd> These options are obsolete and should not be used by new code.
2292** They are retained for backwards compatibility but are now no-ops.
2293** </dd>
2297** <dd>This option is only available if sqlite is compiled with the
2298** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
2299** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
2300** The second should be of type (void*). The callback is invoked by the library
2301** in three separate circumstances, identified by the value passed as the
2302** fourth parameter. If the fourth parameter is 0, then the database connection
2303** passed as the second argument has just been opened. The third argument
2304** points to a buffer containing the name of the main database file. If the
2305** fourth parameter is 1, then the SQL statement that the third parameter
2306** points to has just been executed. Or, if the fourth parameter is 2, then
2307** the connection being passed as the second parameter is being closed. The
2308** third parameter is passed NULL In this case. An example of using this
2309** configuration option can be seen in the "test_sqllog.c" source file in
2310** the canonical SQLite source tree.</dd>
2314** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
2315** that are the default mmap size limit (the default setting for
2316** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
2317** ^The default setting can be overridden by each database connection using
2318** either the [PRAGMA mmap_size] command, or by using the
2319** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size
2320** will be silently truncated if necessary so that it does not exceed the
2321** compile-time maximum mmap size set by the
2322** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
2323** ^If either argument to this option is negative, then that argument is
2324** changed to its compile-time default.
2328** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
2329** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
2330** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
2331** that specifies the maximum size of the created heap.
2335** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
2336** is a pointer to an integer and writes into that integer the number of extra
2337** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
2338** The amount of extra space required can change depending on the compiler,
2339** target platform, and SQLite version.
2343** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
2344** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
2345** sorter to that integer. The default minimum PMA Size is set by the
2346** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched
2347** to help with sort operations when multithreaded sorting
2348** is enabled (using the [PRAGMA threads] command) and the amount of content
2349** to be sorted exceeds the page size times the minimum of the
2350** [PRAGMA cache_size] setting and this value.
2354** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
2355** becomes the [statement journal] spill-to-disk threshold.
2356** [Statement journals] are held in memory until their size (in bytes)
2357** exceeds this threshold, at which point they are written to disk.
2358** Or if the threshold is -1, statement journals are always held
2359** exclusively in memory.
2360** Since many statement journals never become large, setting the spill
2361** threshold to a value such as 64KiB can greatly reduce the amount of
2362** I/O required to support statement rollback.
2363** The default value for this setting is controlled by the
2364** [SQLITE_STMTJRNL_SPILL] compile-time option.
2368** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
2369** of type (int) - the new value of the sorter-reference size threshold.
2370** Usually, when SQLite uses an external sort to order records according
2371** to an ORDER BY clause, all fields required by the caller are present in the
2372** sorted records. However, if SQLite determines based on the declared type
2373** of a table column that its values are likely to be very large - larger
2374** than the configured sorter-reference size threshold - then a reference
2375** is stored in each sorted record and the required column values loaded
2376** from the database as records are returned in sorted order. The default
2377** value for this option is to never use this optimization. Specifying a
2378** negative value for this option restores the default behaviour.
2379** This option is only available if SQLite is compiled with the
2380** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option.
2384** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter
2385** [sqlite3_int64] parameter which is the default maximum size for an in-memory
2386** database created using [sqlite3_deserialize()]. This default maximum
2387** size can be adjusted up or down for individual databases using the
2388** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control]. If this
2389** configuration setting is never used, then the default maximum is determined
2390** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option. If that
2391** compile-time option is not set, then the default maximum is 1073741824.
2392** </dl>
2394#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
2395#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
2396#define SQLITE_CONFIG_SERIALIZED 3 /* nil */
2397#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
2398#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
2399#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */
2400#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
2401#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
2402#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
2403#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
2404#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
2405/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
2406#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
2407#define SQLITE_CONFIG_PCACHE 14 /* no-op */
2408#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
2409#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
2410#define SQLITE_CONFIG_URI 17 /* int */
2411#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
2412#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
2413#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
2414#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
2415#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */
2416#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */
2417#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */
2418#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */
2419#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */
2420#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */
2421#define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */
2422#define SQLITE_CONFIG_MEMDB_MAXSIZE 29 /* sqlite3_int64 */
2425** CAPI3REF: Database Connection Configuration Options
2427** These constants are the available integer configuration options that
2428** can be passed as the second argument to the [sqlite3_db_config()] interface.
2430** New configuration options may be added in future releases of SQLite.
2431** Existing configuration options might be discontinued. Applications
2432** should check the return code from [sqlite3_db_config()] to make sure that
2433** the call worked. ^The [sqlite3_db_config()] interface will return a
2434** non-zero [error code] if a discontinued or unsupported configuration option
2435** is invoked.
2437** <dl>
2440** <dd> ^This option takes three additional arguments that determine the
2441** [lookaside memory allocator] configuration for the [database connection].
2442** ^The first argument (the third parameter to [sqlite3_db_config()] is a
2443** pointer to a memory buffer to use for lookaside memory.
2444** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
2445** may be NULL in which case SQLite will allocate the
2446** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
2447** size of each lookaside buffer slot. ^The third argument is the number of
2448** slots. The size of the buffer in the first argument must be greater than
2449** or equal to the product of the second and third arguments. The buffer
2450** must be aligned to an 8-byte boundary. ^If the second argument to
2451** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
2452** rounded down to the next smaller multiple of 8. ^(The lookaside memory
2453** configuration for a database connection can only be changed when that
2454** connection is not currently using lookaside memory, or in other words
2455** when the "current value" returned by
2456** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
2457** Any attempt to change the lookaside memory configuration when lookaside
2458** memory is in use leaves the configuration unchanged and returns
2459** [SQLITE_BUSY].)^</dd>
2463** <dd> ^This option is used to enable or disable the enforcement of
2464** [foreign key constraints]. There should be two additional arguments.
2465** The first argument is an integer which is 0 to disable FK enforcement,
2466** positive to enable FK enforcement or negative to leave FK enforcement
2467** unchanged. The second parameter is a pointer to an integer into which
2468** is written 0 or 1 to indicate whether FK enforcement is off or on
2469** following this call. The second parameter may be a NULL pointer, in
2470** which case the FK enforcement setting is not reported back. </dd>
2474** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
2475** There should be two additional arguments.
2476** The first argument is an integer which is 0 to disable triggers,
2477** positive to enable triggers or negative to leave the setting unchanged.
2478** The second parameter is a pointer to an integer into which
2479** is written 0 or 1 to indicate whether triggers are disabled or enabled
2480** following this call. The second parameter may be a NULL pointer, in
2481** which case the trigger setting is not reported back.
2483** <p>Originally this option disabled all triggers. ^(However, since
2484** SQLite version 3.35.0, TEMP triggers are still allowed even if
2485** this option is off. So, in other words, this option now only disables
2486** triggers in the main database schema or in the schemas of ATTACH-ed
2487** databases.)^ </dd>
2491** <dd> ^This option is used to enable or disable [CREATE VIEW | views].
2492** There should be two additional arguments.
2493** The first argument is an integer which is 0 to disable views,
2494** positive to enable views or negative to leave the setting unchanged.
2495** The second parameter is a pointer to an integer into which
2496** is written 0 or 1 to indicate whether views are disabled or enabled
2497** following this call. The second parameter may be a NULL pointer, in
2498** which case the view setting is not reported back.
2500** <p>Originally this option disabled all views. ^(However, since
2501** SQLite version 3.35.0, TEMP views are still allowed even if
2502** this option is off. So, in other words, this option now only disables
2503** views in the main database schema or in the schemas of ATTACH-ed
2504** databases.)^ </dd>
2508** <dd> ^This option is used to enable or disable the
2509** [fts3_tokenizer()] function which is part of the
2510** [FTS3] full-text search engine extension.
2511** There should be two additional arguments.
2512** The first argument is an integer which is 0 to disable fts3_tokenizer() or
2513** positive to enable fts3_tokenizer() or negative to leave the setting
2514** unchanged.
2515** The second parameter is a pointer to an integer into which
2516** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
2517** following this call. The second parameter may be a NULL pointer, in
2518** which case the new setting is not reported back. </dd>
2522** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
2523** interface independently of the [load_extension()] SQL function.
2524** The [sqlite3_enable_load_extension()] API enables or disables both the
2525** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
2526** There should be two additional arguments.
2527** When the first argument to this interface is 1, then only the C-API is
2528** enabled and the SQL function remains disabled. If the first argument to
2529** this interface is 0, then both the C-API and the SQL function are disabled.
2530** If the first argument is -1, then no changes are made to state of either the
2531** C-API or the SQL function.
2532** The second parameter is a pointer to an integer into which
2533** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
2534** is disabled or enabled following this call. The second parameter may
2535** be a NULL pointer, in which case the new setting is not reported back.
2536** </dd>
2539** <dd> ^This option is used to change the name of the "main" database
2540** schema. ^The sole argument is a pointer to a constant UTF8 string
2541** which will become the new schema name in place of "main". ^SQLite
2542** does not make a copy of the new main schema name string, so the application
2543** must ensure that the argument passed into this DBCONFIG option is unchanged
2544** until after the database connection closes.
2545** </dd>
2549** <dd> Usually, when a database in wal mode is closed or detached from a
2550** database handle, SQLite checks if this will mean that there are now no
2551** connections at all to the database. If so, it performs a checkpoint
2552** operation before closing the connection. This option may be used to
2553** override this behaviour. The first parameter passed to this operation
2554** is an integer - positive to disable checkpoints-on-close, or zero (the
2555** default) to enable them, and negative to leave the setting unchanged.
2556** The second parameter is a pointer to an integer
2557** into which is written 0 or 1 to indicate whether checkpoints-on-close
2558** have been disabled - 0 if they are not disabled, 1 if they are.
2559** </dd>
2562** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
2563** the [query planner stability guarantee] (QPSG). When the QPSG is active,
2564** a single SQL query statement will always use the same algorithm regardless
2565** of values of [bound parameters].)^ The QPSG disables some query optimizations
2566** that look at the values of bound parameters, which can make some queries
2567** slower. But the QPSG has the advantage of more predictable behavior. With
2568** the QPSG active, SQLite will always use the same query plan in the field as
2569** was used during testing in the lab.
2570** The first argument to this setting is an integer which is 0 to disable
2571** the QPSG, positive to enable QPSG, or negative to leave the setting
2572** unchanged. The second parameter is a pointer to an integer into which
2573** is written 0 or 1 to indicate whether the QPSG is disabled or enabled
2574** following this call.
2575** </dd>
2578** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not
2579** include output for any operations performed by trigger programs. This
2580** option is used to set or clear (the default) a flag that governs this
2581** behavior. The first parameter passed to this operation is an integer -
2582** positive to enable output for trigger programs, or zero to disable it,
2583** or negative to leave the setting unchanged.
2584** The second parameter is a pointer to an integer into which is written
2585** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
2586** it is not disabled, 1 if it is.
2587** </dd>
2590** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
2591** [VACUUM] in order to reset a database back to an empty database
2592** with no schema and no content. The following process works even for
2593** a badly corrupted database file:
2594** <ol>
2595** <li> If the database connection is newly opened, make sure it has read the
2596** database schema by preparing then discarding some query against the
2597** database, or calling sqlite3_table_column_metadata(), ignoring any
2598** errors. This step is only necessary if the application desires to keep
2599** the database in WAL mode after the reset if it was in WAL mode before
2600** the reset.
2601** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
2602** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0);
2603** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
2604** </ol>
2605** Because resetting a database is destructive and irreversible, the
2606** process requires the use of this obscure API and multiple steps to help
2607** ensure that it does not happen by accident.
2610** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the
2611** "defensive" flag for a database connection. When the defensive
2612** flag is enabled, language features that allow ordinary SQL to
2613** deliberately corrupt the database file are disabled. The disabled
2614** features include but are not limited to the following:
2615** <ul>
2616** <li> The [PRAGMA writable_schema=ON] statement.
2617** <li> The [PRAGMA journal_mode=OFF] statement.
2618** <li> Writes to the [sqlite_dbpage] virtual table.
2619** <li> Direct writes to [shadow tables].
2620** </ul>
2621** </dd>
2624** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the
2625** "writable_schema" flag. This has the same effect and is logically equivalent
2626** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF].
2627** The first argument to this setting is an integer which is 0 to disable
2628** the writable_schema, positive to enable writable_schema, or negative to
2629** leave the setting unchanged. The second parameter is a pointer to an
2630** integer into which is written 0 or 1 to indicate whether the writable_schema
2631** is enabled or disabled following this call.
2632** </dd>
2636** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates
2637** the legacy behavior of the [ALTER TABLE RENAME] command such it
2638** behaves as it did prior to [version 3.24.0] (2018-06-04). See the
2639** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for
2640** additional information. This feature can also be turned on and off
2641** using the [PRAGMA legacy_alter_table] statement.
2642** </dd>
2646** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates
2647** the legacy [double-quoted string literal] misfeature for DML statements
2648** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The
2649** default value of this setting is determined by the [-DSQLITE_DQS]
2650** compile-time option.
2651** </dd>
2655** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates
2656** the legacy [double-quoted string literal] misfeature for DDL statements,
2657** such as CREATE TABLE and CREATE INDEX. The
2658** default value of this setting is determined by the [-DSQLITE_DQS]
2659** compile-time option.
2660** </dd>
2664** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to
2665** assume that database schemas are untainted by malicious content.
2666** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite
2667** takes additional defensive steps to protect the application from harm
2668** including:
2669** <ul>
2670** <li> Prohibit the use of SQL functions inside triggers, views,
2671** CHECK constraints, DEFAULT clauses, expression indexes,
2672** partial indexes, or generated columns
2673** unless those functions are tagged with [SQLITE_INNOCUOUS].
2674** <li> Prohibit the use of virtual tables inside of triggers or views
2675** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS].
2676** </ul>
2677** This setting defaults to "on" for legacy compatibility, however
2678** all applications are advised to turn it off if possible. This setting
2679** can also be controlled using the [PRAGMA trusted_schema] statement.
2680** </dd>
2684** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates
2685** the legacy file format flag. When activated, this flag causes all newly
2686** created database file to have a schema format version number (the 4-byte
2687** integer found at offset 44 into the database header) of 1. This in turn
2688** means that the resulting database file will be readable and writable by
2689** any SQLite version back to 3.0.0 ([dateof:3.0.0]). Without this setting,
2690** newly created databases are generally not understandable by SQLite versions
2691** prior to 3.3.0 ([dateof:3.3.0]). As these words are written, there
2692** is now scarcely any need to generated database files that are compatible
2693** all the way back to version 3.0.0, and so this setting is of little
2694** practical use, but is provided so that SQLite can continue to claim the
2695** ability to generate new database files that are compatible with version
2696** 3.0.0.
2697** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on,
2698** the [VACUUM] command will fail with an obscure error when attempting to
2699** process a table with generated columns and a descending index. This is
2700** not considered a bug since SQLite versions 3.3.0 and earlier do not support
2701** either generated columns or decending indexes.
2702** </dd>
2703** </dl>
2705#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */
2706#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
2707#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
2708#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
2709#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
2710#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
2711#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */
2712#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */
2713#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */
2714#define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */
2715#define SQLITE_DBCONFIG_DEFENSIVE 1010 /* int int* */
2716#define SQLITE_DBCONFIG_WRITABLE_SCHEMA 1011 /* int int* */
2717#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE 1012 /* int int* */
2718#define SQLITE_DBCONFIG_DQS_DML 1013 /* int int* */
2719#define SQLITE_DBCONFIG_DQS_DDL 1014 /* int int* */
2720#define SQLITE_DBCONFIG_ENABLE_VIEW 1015 /* int int* */
2721#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT 1016 /* int int* */
2722#define SQLITE_DBCONFIG_TRUSTED_SCHEMA 1017 /* int int* */
2723#define SQLITE_DBCONFIG_MAX 1017 /* Largest DBCONFIG */
2726** CAPI3REF: Enable Or Disable Extended Result Codes
2727** METHOD: sqlite3
2729** ^The sqlite3_extended_result_codes() routine enables or disables the
2730** [extended result codes] feature of SQLite. ^The extended result
2731** codes are disabled by default for historical compatibility.
2733SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
2736** CAPI3REF: Last Insert Rowid
2737** METHOD: sqlite3
2739** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
2740** has a unique 64-bit signed
2741** integer key called the [ROWID | "rowid"]. ^The rowid is always available
2742** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
2743** names are not also used by explicitly declared columns. ^If
2744** the table has a column of type [INTEGER PRIMARY KEY] then that column
2745** is another alias for the rowid.
2747** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
2748** the most recent successful [INSERT] into a rowid table or [virtual table]
2749** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
2750** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
2751** on the database connection D, then sqlite3_last_insert_rowid(D) returns
2752** zero.
2754** As well as being set automatically as rows are inserted into database
2755** tables, the value returned by this function may be set explicitly by
2756** [sqlite3_set_last_insert_rowid()]
2758** Some virtual table implementations may INSERT rows into rowid tables as
2759** part of committing a transaction (e.g. to flush data accumulated in memory
2760** to disk). In this case subsequent calls to this function return the rowid
2761** associated with these internal INSERT operations, which leads to
2762** unintuitive results. Virtual table implementations that do write to rowid
2763** tables in this way can avoid this problem by restoring the original
2764** rowid value using [sqlite3_set_last_insert_rowid()] before returning
2765** control to the user.
2767** ^(If an [INSERT] occurs within a trigger then this routine will
2768** return the [rowid] of the inserted row as long as the trigger is
2769** running. Once the trigger program ends, the value returned
2770** by this routine reverts to what it was before the trigger was fired.)^
2772** ^An [INSERT] that fails due to a constraint violation is not a
2773** successful [INSERT] and does not change the value returned by this
2775** and INSERT OR ABORT make no changes to the return value of this
2776** routine when their insertion fails. ^(When INSERT OR REPLACE
2777** encounters a constraint violation, it does not fail. The
2778** INSERT continues to completion after deleting rows that caused
2779** the constraint problem so INSERT OR REPLACE will always change
2780** the return value of this interface.)^
2782** ^For the purposes of this routine, an [INSERT] is considered to
2783** be successful even if it is subsequently rolled back.
2785** This function is accessible to SQL statements via the
2786** [last_insert_rowid() SQL function].
2788** If a separate thread performs a new [INSERT] on the same
2789** database connection while the [sqlite3_last_insert_rowid()]
2790** function is running and thus changes the last insert [rowid],
2791** then the value returned by [sqlite3_last_insert_rowid()] is
2792** unpredictable and might not equal either the old or the new
2793** last insert [rowid].
2795SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
2798** CAPI3REF: Set the Last Insert Rowid value.
2799** METHOD: sqlite3
2801** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
2802** set the value returned by calling sqlite3_last_insert_rowid(D) to R
2803** without inserting a row into the database.
2805SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
2808** CAPI3REF: Count The Number Of Rows Modified
2809** METHOD: sqlite3
2811** ^These functions return the number of rows modified, inserted or
2812** deleted by the most recently completed INSERT, UPDATE or DELETE
2813** statement on the database connection specified by the only parameter.
2814** The two functions are identical except for the type of the return value
2815** and that if the number of rows modified by the most recent INSERT, UPDATE
2816** or DELETE is greater than the maximum value supported by type "int", then
2817** the return value of sqlite3_changes() is undefined. ^Executing any other
2818** type of SQL statement does not modify the value returned by these functions.
2820** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
2821** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
2822** [foreign key actions] or [REPLACE] constraint resolution are not counted.
2824** Changes to a view that are intercepted by
2825** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
2826** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
2827** DELETE statement run on a view is always zero. Only changes made to real
2828** tables are counted.
2830** Things are more complicated if the sqlite3_changes() function is
2831** executed while a trigger program is running. This may happen if the
2832** program uses the [changes() SQL function], or if some other callback
2833** function invokes sqlite3_changes() directly. Essentially:
2835** <ul>
2836** <li> ^(Before entering a trigger program the value returned by
2837** sqlite3_changes() function is saved. After the trigger program
2838** has finished, the original value is restored.)^
2840** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
2841** statement sets the value returned by sqlite3_changes()
2842** upon completion as normal. Of course, this value will not include
2843** any changes performed by sub-triggers, as the sqlite3_changes()
2844** value will be saved and restored after each sub-trigger has run.)^
2845** </ul>
2847** ^This means that if the changes() SQL function (or similar) is used
2848** by the first INSERT, UPDATE or DELETE statement within a trigger, it
2849** returns the value as set when the calling statement began executing.
2850** ^If it is used by the second or subsequent such statement within a trigger
2851** program, the value returned reflects the number of rows modified by the
2852** previous INSERT, UPDATE or DELETE statement within the same trigger.
2854** If a separate thread makes changes on the same database connection
2855** while [sqlite3_changes()] is running then the value returned
2856** is unpredictable and not meaningful.
2858** See also:
2859** <ul>
2860** <li> the [sqlite3_total_changes()] interface
2861** <li> the [count_changes pragma]
2862** <li> the [changes() SQL function]
2863** <li> the [data_version pragma]
2864** </ul>
2866SQLITE_API int sqlite3_changes(sqlite3*);
2867SQLITE_API sqlite3_int64 sqlite3_changes64(sqlite3*);
2870** CAPI3REF: Total Number Of Rows Modified
2871** METHOD: sqlite3
2873** ^These functions return the total number of rows inserted, modified or
2874** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2875** since the database connection was opened, including those executed as
2876** part of trigger programs. The two functions are identical except for the
2877** type of the return value and that if the number of rows modified by the
2878** connection exceeds the maximum value supported by type "int", then
2879** the return value of sqlite3_total_changes() is undefined. ^Executing
2880** any other type of SQL statement does not affect the value returned by
2881** sqlite3_total_changes().
2883** ^Changes made as part of [foreign key actions] are included in the
2884** count, but those made as part of REPLACE constraint resolution are
2885** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2886** are not counted.
2888** The [sqlite3_total_changes(D)] interface only reports the number
2889** of rows that changed due to SQL statement run against database
2890** connection D. Any changes by other database connections are ignored.
2891** To detect changes against a database file from other database
2892** connections use the [PRAGMA data_version] command or the
2893** [SQLITE_FCNTL_DATA_VERSION] [file control].
2895** If a separate thread makes changes on the same database connection
2896** while [sqlite3_total_changes()] is running then the value
2897** returned is unpredictable and not meaningful.
2899** See also:
2900** <ul>
2901** <li> the [sqlite3_changes()] interface
2902** <li> the [count_changes pragma]
2903** <li> the [changes() SQL function]
2904** <li> the [data_version pragma]
2905** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control]
2906** </ul>
2908SQLITE_API int sqlite3_total_changes(sqlite3*);
2909SQLITE_API sqlite3_int64 sqlite3_total_changes64(sqlite3*);
2912** CAPI3REF: Interrupt A Long-Running Query
2913** METHOD: sqlite3
2915** ^This function causes any pending database operation to abort and
2916** return at its earliest opportunity. This routine is typically
2917** called in response to a user action such as pressing "Cancel"
2918** or Ctrl-C where the user wants a long query operation to halt
2919** immediately.
2921** ^It is safe to call this routine from a thread different from the
2922** thread that is currently running the database operation. But it
2923** is not safe to call this routine with a [database connection] that
2924** is closed or might close before sqlite3_interrupt() returns.
2926** ^If an SQL operation is very nearly finished at the time when
2927** sqlite3_interrupt() is called, then it might not have an opportunity
2928** to be interrupted and might continue to completion.
2930** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2931** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2932** that is inside an explicit transaction, then the entire transaction
2933** will be rolled back automatically.
2935** ^The sqlite3_interrupt(D) call is in effect until all currently running
2936** SQL statements on [database connection] D complete. ^Any new SQL statements
2937** that are started after the sqlite3_interrupt() call and before the
2938** running statement count reaches zero are interrupted as if they had been
2939** running prior to the sqlite3_interrupt() call. ^New SQL statements
2940** that are started after the running statement count reaches zero are
2941** not effected by the sqlite3_interrupt().
2942** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2943** SQL statements is a no-op and has no effect on SQL statements
2944** that are started after the sqlite3_interrupt() call returns.
2946SQLITE_API void sqlite3_interrupt(sqlite3*);
2949** CAPI3REF: Determine If An SQL Statement Is Complete
2951** These routines are useful during command-line input to determine if the
2952** currently entered text seems to form a complete SQL statement or
2953** if additional input is needed before sending the text into
2954** SQLite for parsing. ^These routines return 1 if the input string
2955** appears to be a complete SQL statement. ^A statement is judged to be
2956** complete if it ends with a semicolon token and is not a prefix of a
2957** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within
2958** string literals or quoted identifier names or comments are not
2959** independent tokens (they are part of the token in which they are
2960** embedded) and thus do not count as a statement terminator. ^Whitespace
2961** and comments that follow the final semicolon are ignored.
2963** ^These routines return 0 if the statement is incomplete. ^If a
2964** memory allocation fails, then SQLITE_NOMEM is returned.
2966** ^These routines do not parse the SQL statements thus
2967** will not detect syntactically incorrect SQL.
2969** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2970** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2971** automatically by sqlite3_complete16(). If that initialization fails,
2972** then the return value from sqlite3_complete16() will be non-zero
2973** regardless of whether or not the input SQL is complete.)^
2975** The input to [sqlite3_complete()] must be a zero-terminated
2976** UTF-8 string.
2978** The input to [sqlite3_complete16()] must be a zero-terminated
2979** UTF-16 string in native byte order.
2981SQLITE_API int sqlite3_complete(const char *sql);
2982SQLITE_API int sqlite3_complete16(const void *sql);
2985** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2986** KEYWORDS: {busy-handler callback} {busy handler}
2987** METHOD: sqlite3
2989** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2990** that might be invoked with argument P whenever
2991** an attempt is made to access a database table associated with
2992** [database connection] D when another thread
2993** or process has the table locked.
2994** The sqlite3_busy_handler() interface is used to implement
2995** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2997** ^If the busy callback is NULL, then [SQLITE_BUSY]
2998** is returned immediately upon encountering the lock. ^If the busy callback
2999** is not NULL, then the callback might be invoked with two arguments.
3001** ^The first argument to the busy handler is a copy of the void* pointer which
3002** is the third argument to sqlite3_busy_handler(). ^The second argument to
3003** the busy handler callback is the number of times that the busy handler has
3004** been invoked previously for the same locking event. ^If the
3005** busy callback returns 0, then no additional attempts are made to
3006** access the database and [SQLITE_BUSY] is returned
3007** to the application.
3008** ^If the callback returns non-zero, then another attempt
3009** is made to access the database and the cycle repeats.
3011** The presence of a busy handler does not guarantee that it will be invoked
3012** when there is lock contention. ^If SQLite determines that invoking the busy
3013** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
3014** to the application instead of invoking the
3015** busy handler.
3016** Consider a scenario where one process is holding a read lock that
3017** it is trying to promote to a reserved lock and
3018** a second process is holding a reserved lock that it is trying
3019** to promote to an exclusive lock. The first process cannot proceed
3020** because it is blocked by the second and the second process cannot
3021** proceed because it is blocked by the first. If both processes
3022** invoke the busy handlers, neither will make any progress. Therefore,
3023** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
3024** will induce the first process to release its read lock and allow
3025** the second process to proceed.
3027** ^The default busy callback is NULL.
3029** ^(There can only be a single busy handler defined for each
3030** [database connection]. Setting a new busy handler clears any
3031** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()]
3032** or evaluating [PRAGMA busy_timeout=N] will change the
3033** busy handler and thus clear any previously set busy handler.
3035** The busy callback should not take any actions which modify the
3036** database connection that invoked the busy handler. In other words,
3037** the busy handler is not reentrant. Any such actions
3038** result in undefined behavior.
3040** A busy handler must not close the database connection
3041** or [prepared statement] that invoked the busy handler.
3043SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
3046** CAPI3REF: Set A Busy Timeout
3047** METHOD: sqlite3
3049** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
3050** for a specified amount of time when a table is locked. ^The handler
3051** will sleep multiple times until at least "ms" milliseconds of sleeping
3052** have accumulated. ^After at least "ms" milliseconds of sleeping,
3053** the handler returns 0 which causes [sqlite3_step()] to return
3054** [SQLITE_BUSY].
3056** ^Calling this routine with an argument less than or equal to zero
3057** turns off all busy handlers.
3059** ^(There can only be a single busy handler for a particular
3060** [database connection] at any given moment. If another busy handler
3061** was defined (using [sqlite3_busy_handler()]) prior to calling
3062** this routine, that other busy handler is cleared.)^
3064** See also: [PRAGMA busy_timeout]
3066SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
3069** CAPI3REF: Convenience Routines For Running Queries
3070** METHOD: sqlite3
3072** This is a legacy interface that is preserved for backwards compatibility.
3073** Use of this interface is not recommended.
3075** Definition: A <b>result table</b> is memory data structure created by the
3076** [sqlite3_get_table()] interface. A result table records the
3077** complete query results from one or more queries.
3079** The table conceptually has a number of rows and columns. But
3080** these numbers are not part of the result table itself. These
3081** numbers are obtained separately. Let N be the number of rows
3082** and M be the number of columns.
3084** A result table is an array of pointers to zero-terminated UTF-8 strings.
3085** There are (N+1)*M elements in the array. The first M pointers point
3086** to zero-terminated strings that contain the names of the columns.
3087** The remaining entries all point to query results. NULL values result
3088** in NULL pointers. All other values are in their UTF-8 zero-terminated
3089** string representation as returned by [sqlite3_column_text()].
3091** A result table might consist of one or more memory allocations.
3092** It is not safe to pass a result table directly to [sqlite3_free()].
3093** A result table should be deallocated using [sqlite3_free_table()].
3095** ^(As an example of the result table format, suppose a query result
3096** is as follows:
3098** <blockquote><pre>
3099** Name | Age
3100** -----------------------
3101** Alice | 43
3102** Bob | 28
3103** Cindy | 21
3104** </pre></blockquote>
3106** There are two columns (M==2) and three rows (N==3). Thus the
3107** result table has 8 entries. Suppose the result table is stored
3108** in an array named azResult. Then azResult holds this content:
3110** <blockquote><pre>
3111** azResult&#91;0] = "Name";
3112** azResult&#91;1] = "Age";
3113** azResult&#91;2] = "Alice";
3114** azResult&#91;3] = "43";
3115** azResult&#91;4] = "Bob";
3116** azResult&#91;5] = "28";
3117** azResult&#91;6] = "Cindy";
3118** azResult&#91;7] = "21";
3119** </pre></blockquote>)^
3121** ^The sqlite3_get_table() function evaluates one or more
3122** semicolon-separated SQL statements in the zero-terminated UTF-8
3123** string of its 2nd parameter and returns a result table to the
3124** pointer given in its 3rd parameter.
3126** After the application has finished with the result from sqlite3_get_table(),
3127** it must pass the result table pointer to sqlite3_free_table() in order to
3128** release the memory that was malloced. Because of the way the
3129** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
3130** function must not try to call [sqlite3_free()] directly. Only
3131** [sqlite3_free_table()] is able to release the memory properly and safely.
3133** The sqlite3_get_table() interface is implemented as a wrapper around
3134** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access
3135** to any internal data structures of SQLite. It uses only the public
3136** interface defined here. As a consequence, errors that occur in the
3137** wrapper layer outside of the internal [sqlite3_exec()] call are not
3138** reflected in subsequent calls to [sqlite3_errcode()] or
3139** [sqlite3_errmsg()].
3141SQLITE_API int sqlite3_get_table(
3142 sqlite3 *db, /* An open database */
3143 const char *zSql, /* SQL to be evaluated */
3144 char ***pazResult, /* Results of the query */
3145 int *pnRow, /* Number of result rows written here */
3146 int *pnColumn, /* Number of result columns written here */
3147 char **pzErrmsg /* Error msg written here */
3149SQLITE_API void sqlite3_free_table(char **result);
3152** CAPI3REF: Formatted String Printing Functions
3154** These routines are work-alikes of the "printf()" family of functions
3155** from the standard C library.
3156** These routines understand most of the common formatting options from
3157** the standard library printf()
3158** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]).
3159** See the [built-in printf()] documentation for details.
3161** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
3162** results into memory obtained from [sqlite3_malloc64()].
3163** The strings returned by these two routines should be
3164** released by [sqlite3_free()]. ^Both routines return a
3165** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough
3166** memory to hold the resulting string.
3168** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
3169** the standard C library. The result is written into the
3170** buffer supplied as the second parameter whose size is given by
3171** the first parameter. Note that the order of the
3172** first two parameters is reversed from snprintf().)^ This is an
3173** historical accident that cannot be fixed without breaking
3174** backwards compatibility. ^(Note also that sqlite3_snprintf()
3175** returns a pointer to its buffer instead of the number of
3176** characters actually written into the buffer.)^ We admit that
3177** the number of characters written would be a more useful return
3178** value but we cannot change the implementation of sqlite3_snprintf()
3179** now without breaking compatibility.
3181** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
3182** guarantees that the buffer is always zero-terminated. ^The first
3183** parameter "n" is the total size of the buffer, including space for
3184** the zero terminator. So the longest string that can be completely
3185** written will be n-1 characters.
3187** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
3189** See also: [built-in printf()], [printf() SQL function]
3191SQLITE_API char *sqlite3_mprintf(const char*,...);
3192SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
3193SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
3194SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
3197** CAPI3REF: Memory Allocation Subsystem
3199** The SQLite core uses these three routines for all of its own
3200** internal memory allocation needs. "Core" in the previous sentence
3201** does not include operating-system specific [VFS] implementation. The
3202** Windows VFS uses native malloc() and free() for some operations.
3204** ^The sqlite3_malloc() routine returns a pointer to a block
3205** of memory at least N bytes in length, where N is the parameter.
3206** ^If sqlite3_malloc() is unable to obtain sufficient free
3207** memory, it returns a NULL pointer. ^If the parameter N to
3208** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
3209** a NULL pointer.
3211** ^The sqlite3_malloc64(N) routine works just like
3212** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
3213** of a signed 32-bit integer.
3215** ^Calling sqlite3_free() with a pointer previously returned
3216** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
3217** that it might be reused. ^The sqlite3_free() routine is
3218** a no-op if is called with a NULL pointer. Passing a NULL pointer
3219** to sqlite3_free() is harmless. After being freed, memory
3220** should neither be read nor written. Even reading previously freed
3221** memory might result in a segmentation fault or other severe error.
3222** Memory corruption, a segmentation fault, or other severe error
3223** might result if sqlite3_free() is called with a non-NULL pointer that
3224** was not obtained from sqlite3_malloc() or sqlite3_realloc().
3226** ^The sqlite3_realloc(X,N) interface attempts to resize a
3227** prior memory allocation X to be at least N bytes.
3228** ^If the X parameter to sqlite3_realloc(X,N)
3229** is a NULL pointer then its behavior is identical to calling
3230** sqlite3_malloc(N).
3231** ^If the N parameter to sqlite3_realloc(X,N) is zero or
3232** negative then the behavior is exactly the same as calling
3233** sqlite3_free(X).
3234** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
3235** of at least N bytes in size or NULL if insufficient memory is available.
3236** ^If M is the size of the prior allocation, then min(N,M) bytes
3237** of the prior allocation are copied into the beginning of buffer returned
3238** by sqlite3_realloc(X,N) and the prior allocation is freed.
3239** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
3240** prior allocation is not freed.
3242** ^The sqlite3_realloc64(X,N) interfaces works the same as
3243** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
3244** of a 32-bit signed integer.
3246** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
3247** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
3248** sqlite3_msize(X) returns the size of that memory allocation in bytes.
3249** ^The value returned by sqlite3_msize(X) might be larger than the number
3250** of bytes requested when X was allocated. ^If X is a NULL pointer then
3251** sqlite3_msize(X) returns zero. If X points to something that is not
3252** the beginning of memory allocation, or if it points to a formerly
3253** valid memory allocation that has now been freed, then the behavior
3254** of sqlite3_msize(X) is undefined and possibly harmful.
3256** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
3257** sqlite3_malloc64(), and sqlite3_realloc64()
3258** is always aligned to at least an 8 byte boundary, or to a
3259** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
3260** option is used.
3262** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
3263** must be either NULL or else pointers obtained from a prior
3264** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
3265** not yet been released.
3267** The application must not read or write any part of
3268** a block of memory after it has been released using
3269** [sqlite3_free()] or [sqlite3_realloc()].
3271SQLITE_API void *sqlite3_malloc(int);
3272SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
3273SQLITE_API void *sqlite3_realloc(void*, int);
3274SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
3275SQLITE_API void sqlite3_free(void*);
3276SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
3279** CAPI3REF: Memory Allocator Statistics
3281** SQLite provides these two interfaces for reporting on the status
3282** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
3283** routines, which form the built-in memory allocation subsystem.
3285** ^The [sqlite3_memory_used()] routine returns the number of bytes
3286** of memory currently outstanding (malloced but not freed).
3287** ^The [sqlite3_memory_highwater()] routine returns the maximum
3288** value of [sqlite3_memory_used()] since the high-water mark
3289** was last reset. ^The values returned by [sqlite3_memory_used()] and
3290** [sqlite3_memory_highwater()] include any overhead
3291** added by SQLite in its implementation of [sqlite3_malloc()],
3292** but not overhead added by the any underlying system library
3293** routines that [sqlite3_malloc()] may call.
3295** ^The memory high-water mark is reset to the current value of
3296** [sqlite3_memory_used()] if and only if the parameter to
3297** [sqlite3_memory_highwater()] is true. ^The value returned
3298** by [sqlite3_memory_highwater(1)] is the high-water mark
3299** prior to the reset.
3301SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
3302SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
3305** CAPI3REF: Pseudo-Random Number Generator
3307** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
3308** select random [ROWID | ROWIDs] when inserting new records into a table that
3309** already uses the largest possible [ROWID]. The PRNG is also used for
3310** the built-in random() and randomblob() SQL functions. This interface allows
3311** applications to access the same PRNG for other purposes.
3313** ^A call to this routine stores N bytes of randomness into buffer P.
3314** ^The P parameter can be a NULL pointer.
3316** ^If this routine has not been previously called or if the previous
3317** call had N less than one or a NULL pointer for P, then the PRNG is
3318** seeded using randomness obtained from the xRandomness method of
3319** the default [sqlite3_vfs] object.
3320** ^If the previous call to this routine had an N of 1 or more and a
3321** non-NULL P then the pseudo-randomness is generated
3322** internally and without recourse to the [sqlite3_vfs] xRandomness
3323** method.
3325SQLITE_API void sqlite3_randomness(int N, void *P);
3328** CAPI3REF: Compile-Time Authorization Callbacks
3329** METHOD: sqlite3
3330** KEYWORDS: {authorizer callback}
3332** ^This routine registers an authorizer callback with a particular
3333** [database connection], supplied in the first argument.
3334** ^The authorizer callback is invoked as SQL statements are being compiled
3335** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
3336** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
3337** and [sqlite3_prepare16_v3()]. ^At various
3338** points during the compilation process, as logic is being created
3339** to perform various actions, the authorizer callback is invoked to
3340** see if those actions are allowed. ^The authorizer callback should
3341** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
3342** specific action but allow the SQL statement to continue to be
3343** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
3344** rejected with an error. ^If the authorizer callback returns
3345** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
3346** then the [sqlite3_prepare_v2()] or equivalent call that triggered
3347** the authorizer will fail with an error message.
3349** When the callback returns [SQLITE_OK], that means the operation
3350** requested is ok. ^When the callback returns [SQLITE_DENY], the
3351** [sqlite3_prepare_v2()] or equivalent call that triggered the
3352** authorizer will fail with an error message explaining that
3353** access is denied.
3355** ^The first parameter to the authorizer callback is a copy of the third
3356** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
3357** to the callback is an integer [SQLITE_COPY | action code] that specifies
3358** the particular action to be authorized. ^The third through sixth parameters
3359** to the callback are either NULL pointers or zero-terminated strings
3360** that contain additional details about the action to be authorized.
3361** Applications must always be prepared to encounter a NULL pointer in any
3362** of the third through the sixth parameters of the authorization callback.
3364** ^If the action code is [SQLITE_READ]
3365** and the callback returns [SQLITE_IGNORE] then the
3366** [prepared statement] statement is constructed to substitute
3367** a NULL value in place of the table column that would have
3368** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE]
3369** return can be used to deny an untrusted user access to individual
3370** columns of a table.
3371** ^When a table is referenced by a [SELECT] but no column values are
3372** extracted from that table (for example in a query like
3373** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
3374** is invoked once for that table with a column name that is an empty string.
3375** ^If the action code is [SQLITE_DELETE] and the callback returns
3376** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
3377** [truncate optimization] is disabled and all rows are deleted individually.
3379** An authorizer is used when [sqlite3_prepare | preparing]
3380** SQL statements from an untrusted source, to ensure that the SQL statements
3381** do not try to access data they are not allowed to see, or that they do not
3382** try to execute malicious statements that damage the database. For
3383** example, an application may allow a user to enter arbitrary
3384** SQL queries for evaluation by a database. But the application does
3385** not want the user to be able to make arbitrary changes to the
3386** database. An authorizer could then be put in place while the
3387** user-entered SQL is being [sqlite3_prepare | prepared] that
3388** disallows everything except [SELECT] statements.
3390** Applications that need to process SQL from untrusted sources
3391** might also consider lowering resource limits using [sqlite3_limit()]
3392** and limiting database size using the [max_page_count] [PRAGMA]
3393** in addition to using an authorizer.
3395** ^(Only a single authorizer can be in place on a database connection
3396** at a time. Each call to sqlite3_set_authorizer overrides the
3397** previous call.)^ ^Disable the authorizer by installing a NULL callback.
3398** The authorizer is disabled by default.
3400** The authorizer callback must not do anything that will modify
3401** the database connection that invoked the authorizer callback.
3402** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3403** database connections for the meaning of "modify" in this paragraph.
3405** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
3406** statement might be re-prepared during [sqlite3_step()] due to a
3407** schema change. Hence, the application should ensure that the
3408** correct authorizer callback remains in place during the [sqlite3_step()].
3410** ^Note that the authorizer callback is invoked only during
3411** [sqlite3_prepare()] or its variants. Authorization is not
3412** performed during statement evaluation in [sqlite3_step()], unless
3413** as stated in the previous paragraph, sqlite3_step() invokes
3414** sqlite3_prepare_v2() to reprepare a statement after a schema change.
3416SQLITE_API int sqlite3_set_authorizer(
3417 sqlite3*,
3418 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
3419 void *pUserData
3423** CAPI3REF: Authorizer Return Codes
3425** The [sqlite3_set_authorizer | authorizer callback function] must
3426** return either [SQLITE_OK] or one of these two constants in order
3427** to signal SQLite whether or not the action is permitted. See the
3428** [sqlite3_set_authorizer | authorizer documentation] for additional
3429** information.
3431** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
3432** returned from the [sqlite3_vtab_on_conflict()] interface.
3434#define SQLITE_DENY 1 /* Abort the SQL statement with an error */
3435#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
3438** CAPI3REF: Authorizer Action Codes
3440** The [sqlite3_set_authorizer()] interface registers a callback function
3441** that is invoked to authorize certain SQL statement actions. The
3442** second parameter to the callback is an integer code that specifies
3443** what action is being authorized. These are the integer action codes that
3444** the authorizer callback may be passed.
3446** These action code values signify what kind of operation is to be
3447** authorized. The 3rd and 4th parameters to the authorization
3448** callback function will be parameters or NULL depending on which of these
3449** codes is used as the second parameter. ^(The 5th parameter to the
3450** authorizer callback is the name of the database ("main", "temp",
3451** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback
3452** is the name of the inner-most trigger or view that is responsible for
3453** the access attempt or NULL if this access attempt is directly from
3454** top-level SQL code.
3456/******************************************* 3rd ************ 4th ***********/
3457#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
3458#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
3459#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
3460#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
3461#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
3462#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
3463#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
3464#define SQLITE_CREATE_VIEW 8 /* View Name NULL */
3465#define SQLITE_DELETE 9 /* Table Name NULL */
3466#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
3467#define SQLITE_DROP_TABLE 11 /* Table Name NULL */
3468#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
3469#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
3470#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
3471#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
3472#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
3473#define SQLITE_DROP_VIEW 17 /* View Name NULL */
3474#define SQLITE_INSERT 18 /* Table Name NULL */
3475#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
3476#define SQLITE_READ 20 /* Table Name Column Name */
3477#define SQLITE_SELECT 21 /* NULL NULL */
3478#define SQLITE_TRANSACTION 22 /* Operation NULL */
3479#define SQLITE_UPDATE 23 /* Table Name Column Name */
3480#define SQLITE_ATTACH 24 /* Filename NULL */
3481#define SQLITE_DETACH 25 /* Database Name NULL */
3482#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
3483#define SQLITE_REINDEX 27 /* Index Name NULL */
3484#define SQLITE_ANALYZE 28 /* Table Name NULL */
3485#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
3486#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
3487#define SQLITE_FUNCTION 31 /* NULL Function Name */
3488#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
3489#define SQLITE_COPY 0 /* No longer used */
3490#define SQLITE_RECURSIVE 33 /* NULL NULL */
3493** CAPI3REF: Tracing And Profiling Functions
3494** METHOD: sqlite3
3496** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
3497** instead of the routines described here.
3499** These routines register callback functions that can be used for
3500** tracing and profiling the execution of SQL statements.
3502** ^The callback function registered by sqlite3_trace() is invoked at
3503** various times when an SQL statement is being run by [sqlite3_step()].
3504** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
3505** SQL statement text as the statement first begins executing.
3506** ^(Additional sqlite3_trace() callbacks might occur
3507** as each triggered subprogram is entered. The callbacks for triggers
3508** contain a UTF-8 SQL comment that identifies the trigger.)^
3510** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
3511** the length of [bound parameter] expansion in the output of sqlite3_trace().
3513** ^The callback function registered by sqlite3_profile() is invoked
3514** as each SQL statement finishes. ^The profile callback contains
3515** the original statement text and an estimate of wall-clock time
3516** of how long that statement took to run. ^The profile callback
3517** time is in units of nanoseconds, however the current implementation
3518** is only capable of millisecond resolution so the six least significant
3519** digits in the time are meaningless. Future versions of SQLite
3520** might provide greater resolution on the profiler callback. Invoking
3521** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the
3522** profile callback.
3524SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
3525 void(*xTrace)(void*,const char*), void*);
3526SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
3527 void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
3530** CAPI3REF: SQL Trace Event Codes
3533** These constants identify classes of events that can be monitored
3534** using the [sqlite3_trace_v2()] tracing logic. The M argument
3535** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
3536** the following constants. ^The first argument to the trace callback
3537** is one of the following constants.
3539** New tracing constants may be added in future releases.
3541** ^A trace callback has four arguments: xCallback(T,C,P,X).
3542** ^The T argument is one of the integer type codes above.
3543** ^The C argument is a copy of the context pointer passed in as the
3544** fourth argument to [sqlite3_trace_v2()].
3545** The P and X arguments are pointers whose meanings depend on T.
3547** <dl>
3549** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
3550** first begins running and possibly at other times during the
3551** execution of the prepared statement, such as at the start of each
3552** trigger subprogram. ^The P argument is a pointer to the
3553** [prepared statement]. ^The X argument is a pointer to a string which
3554** is the unexpanded SQL text of the prepared statement or an SQL comment
3555** that indicates the invocation of a trigger. ^The callback can compute
3556** the same text that would have been returned by the legacy [sqlite3_trace()]
3557** interface by using the X argument when X begins with "--" and invoking
3558** [sqlite3_expanded_sql(P)] otherwise.
3561** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
3562** information as is provided by the [sqlite3_profile()] callback.
3563** ^The P argument is a pointer to the [prepared statement] and the
3564** X argument points to a 64-bit integer which is the estimated of
3565** the number of nanosecond that the prepared statement took to run.
3566** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
3569** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
3570** statement generates a single row of result.
3571** ^The P argument is a pointer to the [prepared statement] and the
3572** X argument is unused.
3575** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
3576** connection closes.
3577** ^The P argument is a pointer to the [database connection] object
3578** and the X argument is unused.
3579** </dl>
3581#define SQLITE_TRACE_STMT 0x01
3582#define SQLITE_TRACE_PROFILE 0x02
3583#define SQLITE_TRACE_ROW 0x04
3584#define SQLITE_TRACE_CLOSE 0x08
3587** CAPI3REF: SQL Trace Hook
3588** METHOD: sqlite3
3590** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
3591** function X against [database connection] D, using property mask M
3592** and context pointer P. ^If the X callback is
3593** NULL or if the M mask is zero, then tracing is disabled. The
3594** M argument should be the bitwise OR-ed combination of
3595** zero or more [SQLITE_TRACE] constants.
3597** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides
3598** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2().
3600** ^The X callback is invoked whenever any of the events identified by
3601** mask M occur. ^The integer return value from the callback is currently
3602** ignored, though this may change in future releases. Callback
3603** implementations should return zero to ensure future compatibility.
3605** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
3606** ^The T argument is one of the [SQLITE_TRACE]
3607** constants to indicate why the callback was invoked.
3608** ^The C argument is a copy of the context pointer.
3609** The P and X arguments are pointers whose meanings depend on T.
3611** The sqlite3_trace_v2() interface is intended to replace the legacy
3612** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
3613** are deprecated.
3615SQLITE_API int sqlite3_trace_v2(
3616 sqlite3*,
3617 unsigned uMask,
3618 int(*xCallback)(unsigned,void*,void*,void*),
3619 void *pCtx
3623** CAPI3REF: Query Progress Callbacks
3624** METHOD: sqlite3
3626** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
3627** function X to be invoked periodically during long running calls to
3628** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
3629** database connection D. An example use for this
3630** interface is to keep a GUI updated during a large query.
3632** ^The parameter P is passed through as the only parameter to the
3633** callback function X. ^The parameter N is the approximate number of
3634** [virtual machine instructions] that are evaluated between successive
3635** invocations of the callback X. ^If N is less than one then the progress
3636** handler is disabled.
3638** ^Only a single progress handler may be defined at one time per
3639** [database connection]; setting a new progress handler cancels the
3640** old one. ^Setting parameter X to NULL disables the progress handler.
3641** ^The progress handler is also disabled by setting N to a value less
3642** than 1.
3644** ^If the progress callback returns non-zero, the operation is
3645** interrupted. This feature can be used to implement a
3646** "Cancel" button on a GUI progress dialog box.
3648** The progress handler callback must not do anything that will modify
3649** the database connection that invoked the progress handler.
3650** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
3651** database connections for the meaning of "modify" in this paragraph.
3654SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
3657** CAPI3REF: Opening A New Database Connection
3658** CONSTRUCTOR: sqlite3
3660** ^These routines open an SQLite database file as specified by the
3661** filename argument. ^The filename argument is interpreted as UTF-8 for
3662** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
3663** order for sqlite3_open16(). ^(A [database connection] handle is usually
3664** returned in *ppDb, even if an error occurs. The only exception is that
3665** if SQLite is unable to allocate memory to hold the [sqlite3] object,
3666** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
3667** object.)^ ^(If the database is opened (and/or created) successfully, then
3668** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The
3669** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
3670** an English language description of the error following a failure of any
3671** of the sqlite3_open() routines.
3673** ^The default encoding will be UTF-8 for databases created using
3674** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases
3675** created using sqlite3_open16() will be UTF-16 in the native byte order.
3677** Whether or not an error occurs when it is opened, resources
3678** associated with the [database connection] handle should be released by
3679** passing it to [sqlite3_close()] when it is no longer required.
3681** The sqlite3_open_v2() interface works like sqlite3_open()
3682** except that it accepts two additional parameters for additional control
3683** over the new database connection. ^(The flags parameter to
3684** sqlite3_open_v2() must include, at a minimum, one of the following
3685** three flag combinations:)^
3687** <dl>
3688** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
3689** <dd>The database is opened in read-only mode. If the database does not
3690** already exist, an error is returned.</dd>)^
3692** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
3693** <dd>The database is opened for reading and writing if possible, or reading
3694** only if the file is write protected by the operating system. In either
3695** case the database must already exist, otherwise an error is returned.</dd>)^
3698** <dd>The database is opened for reading and writing, and is created if
3699** it does not already exist. This is the behavior that is always used for
3700** sqlite3_open() and sqlite3_open16().</dd>)^
3701** </dl>
3703** In addition to the required flags, the following optional flags are
3704** also supported:
3706** <dl>
3707** ^(<dt>[SQLITE_OPEN_URI]</dt>
3708** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^
3710** ^(<dt>[SQLITE_OPEN_MEMORY]</dt>
3711** <dd>The database will be opened as an in-memory database. The database
3712** is named by the "filename" argument for the purposes of cache-sharing,
3713** if shared cache mode is enabled, but the "filename" is otherwise ignored.
3714** </dd>)^
3716** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt>
3717** <dd>The new database connection will use the "multi-thread"
3718** [threading mode].)^ This means that separate threads are allowed
3719** to use SQLite at the same time, as long as each thread is using
3720** a different [database connection].
3722** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt>
3723** <dd>The new database connection will use the "serialized"
3724** [threading mode].)^ This means the multiple threads can safely
3725** attempt to use the same database connection at the same time.
3726** (Mutexes will block any actual concurrency, but in this mode
3727** there is no harm in trying.)
3729** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt>
3730** <dd>The database is opened [shared cache] enabled, overriding
3731** the default shared cache setting provided by
3732** [sqlite3_enable_shared_cache()].)^
3734** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt>
3735** <dd>The database is opened [shared cache] disabled, overriding
3736** the default shared cache setting provided by
3737** [sqlite3_enable_shared_cache()].)^
3740** <dd>The database connection comes up in "extended result code mode".
3741** In other words, the database behaves has if
3742** [sqlite3_extended_result_codes(db,1)] where called on the database
3743** connection as soon as the connection is created. In addition to setting
3744** the extended result code mode, this flag also causes [sqlite3_open_v2()]
3745** to return an extended result code.</dd>
3748** <dd>The database filename is not allowed to be a symbolic link</dd>
3749** </dl>)^
3751** If the 3rd parameter to sqlite3_open_v2() is not one of the
3752** required combinations shown above optionally combined with other
3754** then the behavior is undefined. Historic versions of SQLite
3755** have silently ignored surplus bits in the flags parameter to
3756** sqlite3_open_v2(), however that behavior might not be carried through
3757** into future versions of SQLite and so applications should not rely
3758** upon it. Note in particular that the SQLITE_OPEN_EXCLUSIVE flag is a no-op
3759** for sqlite3_open_v2(). The SQLITE_OPEN_EXCLUSIVE does *not* cause
3760** the open to fail if the database already exists. The SQLITE_OPEN_EXCLUSIVE
3761** flag is intended for use by the [sqlite3_vfs|VFS interface] only, and not
3762** by sqlite3_open_v2().
3764** ^The fourth parameter to sqlite3_open_v2() is the name of the
3765** [sqlite3_vfs] object that defines the operating system interface that
3766** the new database connection should use. ^If the fourth parameter is
3767** a NULL pointer then the default [sqlite3_vfs] object is used.
3769** ^If the filename is ":memory:", then a private, temporary in-memory database
3770** is created for the connection. ^This in-memory database will vanish when
3771** the database connection is closed. Future versions of SQLite might
3772** make use of additional special filenames that begin with the ":" character.
3773** It is recommended that when a database filename actually does begin with
3774** a ":" character you should prefix the filename with a pathname such as
3775** "./" to avoid ambiguity.
3777** ^If the filename is an empty string, then a private, temporary
3778** on-disk database will be created. ^This private database will be
3779** automatically deleted as soon as the database connection is closed.
3781** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
3783** ^If [URI filename] interpretation is enabled, and the filename argument
3784** begins with "file:", then the filename is interpreted as a URI. ^URI
3785** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
3786** set in the third argument to sqlite3_open_v2(), or if it has
3787** been enabled globally using the [SQLITE_CONFIG_URI] option with the
3788** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
3789** URI filename interpretation is turned off
3790** by default, but future releases of SQLite might enable URI filename
3791** interpretation by default. See "[URI filenames]" for additional
3792** information.
3794** URI filenames are parsed according to RFC 3986. ^If the URI contains an
3795** authority, then it must be either an empty string or the string
3796** "localhost". ^If the authority is not an empty string or "localhost", an
3797** error is returned to the caller. ^The fragment component of a URI, if
3798** present, is ignored.
3800** ^SQLite uses the path component of the URI as the name of the disk file
3801** which contains the database. ^If the path begins with a '/' character,
3802** then it is interpreted as an absolute path. ^If the path does not begin
3803** with a '/' (meaning that the authority section is omitted from the URI)
3804** then the path is interpreted as a relative path.
3805** ^(On windows, the first component of an absolute path
3806** is a drive specification (e.g. "C:").)^
3808** [[core URI query parameters]]
3809** The query component of a URI may contain parameters that are interpreted
3810** either by SQLite itself, or by a [VFS | custom VFS implementation].
3811** SQLite and its built-in [VFSes] interpret the
3812** following query parameters:
3814** <ul>
3815** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
3816** a VFS object that provides the operating system interface that should
3817** be used to access the database file on disk. ^If this option is set to
3818** an empty string the default VFS object is used. ^Specifying an unknown
3819** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
3820** present, then the VFS specified by the option takes precedence over
3821** the value passed as the fourth parameter to sqlite3_open_v2().
3823** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
3824** "rwc", or "memory". Attempting to set it to any other value is
3825** an error)^.
3826** ^If "ro" is specified, then the database is opened for read-only
3827** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
3828** third argument to sqlite3_open_v2(). ^If the mode option is set to
3829** "rw", then the database is opened for read-write (but not create)
3830** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
3831** been set. ^Value "rwc" is equivalent to setting both
3832** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is
3833** set to "memory" then a pure [in-memory database] that never reads
3834** or writes from disk is used. ^It is an error to specify a value for
3835** the mode parameter that is less restrictive than that specified by
3836** the flags passed in the third parameter to sqlite3_open_v2().
3838** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
3839** "private". ^Setting it to "shared" is equivalent to setting the
3840** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
3841** sqlite3_open_v2(). ^Setting the cache parameter to "private" is
3842** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
3843** ^If sqlite3_open_v2() is used and the "cache" parameter is present in
3844** a URI filename, its value overrides any behavior requested by setting
3847** <li> <b>psow</b>: ^The psow parameter indicates whether or not the
3848** [powersafe overwrite] property does or does not apply to the
3849** storage media on which the database file resides.
3851** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
3852** which if set disables file locking in rollback journal modes. This
3853** is useful for accessing a database on a filesystem that does not
3854** support locking. Caution: Database corruption might result if two
3855** or more processes write to the same database and any one of those
3856** processes uses nolock=1.
3858** <li> <b>immutable</b>: ^The immutable parameter is a boolean query
3859** parameter that indicates that the database file is stored on
3860** read-only media. ^When immutable is set, SQLite assumes that the
3861** database file cannot be changed, even by a process with higher
3862** privilege, and so the database is opened read-only and all locking
3863** and change detection is disabled. Caution: Setting the immutable
3864** property on a database file that does in fact change can result
3865** in incorrect query results and/or [SQLITE_CORRUPT] errors.
3866** See also: [SQLITE_IOCAP_IMMUTABLE].
3868** </ul>
3870** ^Specifying an unknown parameter in the query component of a URI is not an
3871** error. Future versions of SQLite might understand additional query
3872** parameters. See "[query parameters with special meaning to SQLite]" for
3873** additional information.
3875** [[URI filename examples]] <h3>URI filename examples</h3>
3877** <table border="1" align=center cellpadding=5>
3878** <tr><th> URI filenames <th> Results
3879** <tr><td> file:data.db <td>
3880** Open the file "data.db" in the current directory.
3881** <tr><td> file:/home/fred/data.db<br>
3882** file:///home/fred/data.db <br>
3883** file://localhost/home/fred/data.db <br> <td>
3884** Open the database file "/home/fred/data.db".
3885** <tr><td> file://darkstar/home/fred/data.db <td>
3886** An error. "darkstar" is not a recognized authority.
3887** <tr><td style="white-space:nowrap">
3888** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
3889** <td> Windows only: Open the file "data.db" on fred's desktop on drive
3890** C:. Note that the %20 escaping in this example is not strictly
3891** necessary - space characters can be used literally
3892** in URI filenames.
3893** <tr><td> file:data.db?mode=ro&cache=private <td>
3894** Open file "data.db" in the current directory for read-only access.
3895** Regardless of whether or not shared-cache mode is enabled by
3896** default, use a private cache.
3897** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
3898** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
3899** that uses dot-files in place of posix advisory locking.
3900** <tr><td> file:data.db?mode=readonly <td>
3901** An error. "readonly" is not a valid option for the "mode" parameter.
3902** Use "ro" instead: "file:data.db?mode=ro".
3903** </table>
3905** ^URI hexadecimal escape sequences (%HH) are supported within the path and
3906** query components of a URI. A hexadecimal escape sequence consists of a
3907** percent sign - "%" - followed by exactly two hexadecimal digits
3908** specifying an octet value. ^Before the path or query components of a
3909** URI filename are interpreted, they are encoded using UTF-8 and all
3910** hexadecimal escape sequences replaced by a single byte containing the
3911** corresponding octet. If this process generates an invalid UTF-8 encoding,
3912** the results are undefined.
3914** <b>Note to Windows users:</b> The encoding used for the filename argument
3915** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
3916** codepage is currently defined. Filenames containing international
3917** characters must be converted to UTF-8 prior to passing them into
3918** sqlite3_open() or sqlite3_open_v2().
3920** <b>Note to Windows Runtime users:</b> The temporary directory must be set
3921** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
3922** features that require the use of temporary files may fail.
3924** See also: [sqlite3_temp_directory]
3926SQLITE_API int sqlite3_open(
3927 const char *filename, /* Database filename (UTF-8) */
3928 sqlite3 **ppDb /* OUT: SQLite db handle */
3930SQLITE_API int sqlite3_open16(
3931 const void *filename, /* Database filename (UTF-16) */
3932 sqlite3 **ppDb /* OUT: SQLite db handle */
3934SQLITE_API int sqlite3_open_v2(
3935 const char *filename, /* Database filename (UTF-8) */
3936 sqlite3 **ppDb, /* OUT: SQLite db handle */
3937 int flags, /* Flags */
3938 const char *zVfs /* Name of VFS module to use */
3942** CAPI3REF: Obtain Values For URI Parameters
3944** These are utility routines, useful to [VFS|custom VFS implementations],
3945** that check if a database file was a URI that contained a specific query
3946** parameter, and if so obtains the value of that query parameter.
3948** The first parameter to these interfaces (hereafter referred to
3949** as F) must be one of:
3950** <ul>
3951** <li> A database filename pointer created by the SQLite core and
3952** passed into the xOpen() method of a VFS implemention, or
3953** <li> A filename obtained from [sqlite3_db_filename()], or
3954** <li> A new filename constructed using [sqlite3_create_filename()].
3955** </ul>
3956** If the F parameter is not one of the above, then the behavior is
3957** undefined and probably undesirable. Older versions of SQLite were
3958** more tolerant of invalid F parameters than newer versions.
3960** If F is a suitable filename (as described in the previous paragraph)
3961** and if P is the name of the query parameter, then
3962** sqlite3_uri_parameter(F,P) returns the value of the P
3963** parameter if it exists or a NULL pointer if P does not appear as a
3964** query parameter on F. If P is a query parameter of F and it
3965** has no explicit value, then sqlite3_uri_parameter(F,P) returns
3966** a pointer to an empty string.
3968** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
3969** parameter and returns true (1) or false (0) according to the value
3970** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3971** value of query parameter P is one of "yes", "true", or "on" in any
3972** case or if the value begins with a non-zero number. The
3973** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3974** query parameter P is one of "no", "false", or "off" in any case or
3975** if the value begins with a numeric zero. If P is not a query
3976** parameter on F or if the value of P does not match any of the
3977** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3979** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3980** 64-bit signed integer and returns that integer, or D if P does not
3981** exist. If the value of P is something other than an integer, then
3982** zero is returned.
3984** The sqlite3_uri_key(F,N) returns a pointer to the name (not
3985** the value) of the N-th query parameter for filename F, or a NULL
3986** pointer if N is less than zero or greater than the number of query
3987** parameters minus 1. The N value is zero-based so N should be 0 to obtain
3988** the name of the first query parameter, 1 for the second parameter, and
3989** so forth.
3991** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3992** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
3993** is not a database file pathname pointer that the SQLite core passed
3994** into the xOpen VFS method, then the behavior of this routine is undefined
3995** and probably undesirable.
3997** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F
3998** parameter can also be the name of a rollback journal file or WAL file
3999** in addition to the main database file. Prior to version 3.31.0, these
4000** routines would only work if F was the name of the main database file.
4001** When the F parameter is the name of the rollback journal or WAL file,
4002** it has access to all the same query parameters as were found on the
4003** main database file.
4005** See the [URI filename] documentation for additional information.
4007SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
4008SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
4009SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
4010SQLITE_API const char *sqlite3_uri_key(const char *zFilename, int N);
4013** CAPI3REF: Translate filenames
4015** These routines are available to [VFS|custom VFS implementations] for
4016** translating filenames between the main database file, the journal file,
4017** and the WAL file.
4019** If F is the name of an sqlite database file, journal file, or WAL file
4020** passed by the SQLite core into the VFS, then sqlite3_filename_database(F)
4021** returns the name of the corresponding database file.
4023** If F is the name of an sqlite database file, journal file, or WAL file
4024** passed by the SQLite core into the VFS, or if F is a database filename
4025** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F)
4026** returns the name of the corresponding rollback journal file.
4028** If F is the name of an sqlite database file, journal file, or WAL file
4029** that was passed by the SQLite core into the VFS, or if F is a database
4030** filename obtained from [sqlite3_db_filename()], then
4031** sqlite3_filename_wal(F) returns the name of the corresponding
4032** WAL file.
4034** In all of the above, if F is not the name of a database, journal or WAL
4035** filename passed into the VFS from the SQLite core and F is not the
4036** return value from [sqlite3_db_filename()], then the result is
4037** undefined and is likely a memory access violation.
4039SQLITE_API const char *sqlite3_filename_database(const char*);
4040SQLITE_API const char *sqlite3_filename_journal(const char*);
4041SQLITE_API const char *sqlite3_filename_wal(const char*);
4044** CAPI3REF: Database File Corresponding To A Journal
4046** ^If X is the name of a rollback or WAL-mode journal file that is
4047** passed into the xOpen method of [sqlite3_vfs], then
4048** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file]
4049** object that represents the main database file.
4051** This routine is intended for use in custom [VFS] implementations
4052** only. It is not a general-purpose interface.
4053** The argument sqlite3_file_object(X) must be a filename pointer that
4054** has been passed into [sqlite3_vfs].xOpen method where the
4055** flags parameter to xOpen contains one of the bits
4057** of this routine results in undefined and probably undesirable
4058** behavior.
4060SQLITE_API sqlite3_file *sqlite3_database_file_object(const char*);
4063** CAPI3REF: Create and Destroy VFS Filenames
4065** These interfces are provided for use by [VFS shim] implementations and
4066** are not useful outside of that context.
4068** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of
4069** database filename D with corresponding journal file J and WAL file W and
4070** with N URI parameters key/values pairs in the array P. The result from
4071** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that
4072** is safe to pass to routines like:
4073** <ul>
4074** <li> [sqlite3_uri_parameter()],
4075** <li> [sqlite3_uri_boolean()],
4076** <li> [sqlite3_uri_int64()],
4077** <li> [sqlite3_uri_key()],
4078** <li> [sqlite3_filename_database()],
4079** <li> [sqlite3_filename_journal()], or
4080** <li> [sqlite3_filename_wal()].
4081** </ul>
4082** If a memory allocation error occurs, sqlite3_create_filename() might
4083** return a NULL pointer. The memory obtained from sqlite3_create_filename(X)
4084** must be released by a corresponding call to sqlite3_free_filename(Y).
4086** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array
4087** of 2*N pointers to strings. Each pair of pointers in this array corresponds
4088** to a key and value for a query parameter. The P parameter may be a NULL
4089** pointer if N is zero. None of the 2*N pointers in the P array may be
4090** NULL pointers and key pointers should not be empty strings.
4091** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may
4092** be NULL pointers, though they can be empty strings.
4094** The sqlite3_free_filename(Y) routine releases a memory allocation
4095** previously obtained from sqlite3_create_filename(). Invoking
4096** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op.
4098** If the Y parameter to sqlite3_free_filename(Y) is anything other
4099** than a NULL pointer or a pointer previously acquired from
4100** sqlite3_create_filename(), then bad things such as heap
4101** corruption or segfaults may occur. The value Y should not be
4102** used again after sqlite3_free_filename(Y) has been called. This means
4103** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y,
4104** then the corresponding [sqlite3_module.xClose() method should also be
4105** invoked prior to calling sqlite3_free_filename(Y).
4107SQLITE_API char *sqlite3_create_filename(
4108 const char *zDatabase,
4109 const char *zJournal,
4110 const char *zWal,
4111 int nParam,
4112 const char **azParam
4114SQLITE_API void sqlite3_free_filename(char*);
4117** CAPI3REF: Error Codes And Messages
4118** METHOD: sqlite3
4120** ^If the most recent sqlite3_* API call associated with
4121** [database connection] D failed, then the sqlite3_errcode(D) interface
4122** returns the numeric [result code] or [extended result code] for that
4123** API call.
4124** ^The sqlite3_extended_errcode()
4125** interface is the same except that it always returns the
4126** [extended result code] even when extended result codes are
4127** disabled.
4129** The values returned by sqlite3_errcode() and/or
4130** sqlite3_extended_errcode() might change with each API call.
4131** Except, there are some interfaces that are guaranteed to never
4132** change the value of the error code. The error-code preserving
4133** interfaces include the following:
4135** <ul>
4136** <li> sqlite3_errcode()
4137** <li> sqlite3_extended_errcode()
4138** <li> sqlite3_errmsg()
4139** <li> sqlite3_errmsg16()
4140** <li> sqlite3_error_offset()
4141** </ul>
4143** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
4144** text that describes the error, as either UTF-8 or UTF-16 respectively.
4145** ^(Memory to hold the error message string is managed internally.
4146** The application does not need to worry about freeing the result.
4147** However, the error string might be overwritten or deallocated by
4148** subsequent calls to other SQLite interface functions.)^
4150** ^The sqlite3_errstr() interface returns the English-language text
4151** that describes the [result code], as UTF-8.
4152** ^(Memory to hold the error message string is managed internally
4153** and must not be freed by the application)^.
4155** ^If the most recent error references a specific token in the input
4156** SQL, the sqlite3_error_offset() interface returns the byte offset
4157** of the start of that token. ^The byte offset returned by
4158** sqlite3_error_offset() assumes that the input SQL is UTF8.
4159** ^If the most recent error does not reference a specific token in the input
4160** SQL, then the sqlite3_error_offset() function returns -1.
4162** When the serialized [threading mode] is in use, it might be the
4163** case that a second error occurs on a separate thread in between
4164** the time of the first error and the call to these interfaces.
4165** When that happens, the second error will be reported since these
4166** interfaces always report the most recent result. To avoid
4167** this, each thread can obtain exclusive use of the [database connection] D
4168** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
4169** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
4170** all calls to the interfaces listed here are completed.
4172** If an interface fails with SQLITE_MISUSE, that means the interface
4173** was invoked incorrectly by the application. In that case, the
4174** error code and message may or may not be set.
4176SQLITE_API int sqlite3_errcode(sqlite3 *db);
4177SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
4178SQLITE_API const char *sqlite3_errmsg(sqlite3*);
4179SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
4180SQLITE_API const char *sqlite3_errstr(int);
4181SQLITE_API int sqlite3_error_offset(sqlite3 *db);
4184** CAPI3REF: Prepared Statement Object
4185** KEYWORDS: {prepared statement} {prepared statements}
4187** An instance of this object represents a single SQL statement that
4188** has been compiled into binary form and is ready to be evaluated.
4190** Think of each SQL statement as a separate computer program. The
4191** original SQL text is source code. A prepared statement object
4192** is the compiled object code. All SQL must be converted into a
4193** prepared statement before it can be run.
4195** The life-cycle of a prepared statement object usually goes like this:
4197** <ol>
4198** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
4199** <li> Bind values to [parameters] using the sqlite3_bind_*()
4200** interfaces.
4201** <li> Run the SQL by calling [sqlite3_step()] one or more times.
4202** <li> Reset the prepared statement using [sqlite3_reset()] then go back
4203** to step 2. Do this zero or more times.
4204** <li> Destroy the object using [sqlite3_finalize()].
4205** </ol>
4207typedef struct sqlite3_stmt sqlite3_stmt;
4210** CAPI3REF: Run-time Limits
4211** METHOD: sqlite3
4213** ^(This interface allows the size of various constructs to be limited
4214** on a connection by connection basis. The first parameter is the
4215** [database connection] whose limit is to be set or queried. The
4216** second parameter is one of the [limit categories] that define a
4217** class of constructs to be size limited. The third parameter is the
4218** new limit for that construct.)^
4220** ^If the new limit is a negative number, the limit is unchanged.
4221** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
4222** [limits | hard upper bound]
4223** set at compile-time by a C preprocessor macro called
4224** [limits | SQLITE_MAX_<i>NAME</i>].
4225** (The "_LIMIT_" in the name is changed to "_MAX_".))^
4226** ^Attempts to increase a limit above its hard upper bound are
4227** silently truncated to the hard upper bound.
4229** ^Regardless of whether or not the limit was changed, the
4230** [sqlite3_limit()] interface returns the prior value of the limit.
4231** ^Hence, to find the current value of a limit without changing it,
4232** simply invoke this interface with the third parameter set to -1.
4234** Run-time limits are intended for use in applications that manage
4235** both their own internal database and also databases that are controlled
4236** by untrusted external sources. An example application might be a
4237** web browser that has its own databases for storing history and
4238** separate databases controlled by JavaScript applications downloaded
4239** off the Internet. The internal databases can be given the
4240** large, default limits. Databases managed by external sources can
4241** be given much smaller limits designed to prevent a denial of service
4242** attack. Developers might also want to use the [sqlite3_set_authorizer()]
4243** interface to further control untrusted SQL. The size of the database
4244** created by an untrusted script can be contained using the
4245** [max_page_count] [PRAGMA].
4247** New run-time limit categories may be added in future releases.
4249SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
4252** CAPI3REF: Run-Time Limit Categories
4253** KEYWORDS: {limit category} {*limit categories}
4255** These constants define various performance limits
4256** that can be lowered at run-time using [sqlite3_limit()].
4257** The synopsis of the meanings of the various limits is shown below.
4258** Additional information is available at [limits | Limits in SQLite].
4260** <dl>
4262** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
4265** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
4268** <dd>The maximum number of columns in a table definition or in the
4269** result set of a [SELECT] or the maximum number of columns in an index
4270** or in an ORDER BY or GROUP BY clause.</dd>)^
4273** <dd>The maximum depth of the parse tree on any expression.</dd>)^
4276** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
4279** <dd>The maximum number of instructions in a virtual machine program
4280** used to implement an SQL statement. If [sqlite3_prepare_v2()] or
4281** the equivalent tries to allocate space for more than this many opcodes
4282** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
4285** <dd>The maximum number of arguments on a function.</dd>)^
4288** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
4292** <dd>The maximum length of the pattern argument to the [LIKE] or
4293** [GLOB] operators.</dd>)^
4297** <dd>The maximum index number of any [parameter] in an SQL statement.)^
4300** <dd>The maximum depth of recursion for triggers.</dd>)^
4303** <dd>The maximum number of auxiliary worker threads that a single
4304** [prepared statement] may start.</dd>)^
4305** </dl>
4312#define SQLITE_LIMIT_VDBE_OP 5
4321** CAPI3REF: Prepare Flags
4323** These constants define various flags that can be passed into
4324** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
4325** [sqlite3_prepare16_v3()] interfaces.
4327** New flags may be added in future releases of SQLite.
4329** <dl>
4331** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
4332** that the prepared statement will be retained for a long time and
4333** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
4334** and [sqlite3_prepare16_v3()] assume that the prepared statement will
4335** be used just once or at most a few times and then destroyed using
4336** [sqlite3_finalize()] relatively soon. The current implementation acts
4337** on this hint by avoiding the use of [lookaside memory] so as not to
4338** deplete the limited store of lookaside memory. Future versions of
4339** SQLite may act on this hint differently.
4342** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
4343** to be required for any prepared statement that wanted to use the
4344** [sqlite3_normalized_sql()] interface. However, the
4345** [sqlite3_normalized_sql()] interface is now available to all
4346** prepared statements, regardless of whether or not they use this
4347** flag.
4350** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler
4351** to return an error (error code SQLITE_ERROR) if the statement uses
4352** any virtual tables.
4353** </dl>
4357#define SQLITE_PREPARE_NO_VTAB 0x04
4360** CAPI3REF: Compiling An SQL Statement
4361** KEYWORDS: {SQL statement compiler}
4362** METHOD: sqlite3
4363** CONSTRUCTOR: sqlite3_stmt
4365** To execute an SQL statement, it must first be compiled into a byte-code
4366** program using one of these routines. Or, in other words, these routines
4367** are constructors for the [prepared statement] object.
4369** The preferred routine to use is [sqlite3_prepare_v2()]. The
4370** [sqlite3_prepare()] interface is legacy and should be avoided.
4371** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
4372** for special purposes.
4374** The use of the UTF-8 interfaces is preferred, as SQLite currently
4375** does all parsing using UTF-8. The UTF-16 interfaces are provided
4376** as a convenience. The UTF-16 interfaces work by converting the
4377** input text into UTF-8, then invoking the corresponding UTF-8 interface.
4379** The first argument, "db", is a [database connection] obtained from a
4380** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
4381** [sqlite3_open16()]. The database connection must not have been closed.
4383** The second argument, "zSql", is the statement to be compiled, encoded
4384** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(),
4385** and sqlite3_prepare_v3()
4386** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
4387** and sqlite3_prepare16_v3() use UTF-16.
4389** ^If the nByte argument is negative, then zSql is read up to the
4390** first zero terminator. ^If nByte is positive, then it is the
4391** number of bytes read from zSql. ^If nByte is zero, then no prepared
4392** statement is generated.
4393** If the caller knows that the supplied string is nul-terminated, then
4394** there is a small performance advantage to passing an nByte parameter that
4395** is the number of bytes in the input string <i>including</i>
4396** the nul-terminator.
4398** ^If pzTail is not NULL then *pzTail is made to point to the first byte
4399** past the end of the first SQL statement in zSql. These routines only
4400** compile the first statement in zSql, so *pzTail is left pointing to
4401** what remains uncompiled.
4403** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
4404** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set
4405** to NULL. ^If the input text contains no SQL (if the input is an empty
4406** string or a comment) then *ppStmt is set to NULL.
4407** The calling procedure is responsible for deleting the compiled
4408** SQL statement using [sqlite3_finalize()] after it has finished with it.
4409** ppStmt may not be NULL.
4411** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
4412** otherwise an [error code] is returned.
4414** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
4415** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
4416** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
4417** are retained for backwards compatibility, but their use is discouraged.
4418** ^In the "vX" interfaces, the prepared statement
4419** that is returned (the [sqlite3_stmt] object) contains a copy of the
4420** original SQL text. This causes the [sqlite3_step()] interface to
4421** behave differently in three ways:
4423** <ol>
4424** <li>
4425** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
4426** always used to do, [sqlite3_step()] will automatically recompile the SQL
4427** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
4428** retries will occur before sqlite3_step() gives up and returns an error.
4429** </li>
4431** <li>
4432** ^When an error occurs, [sqlite3_step()] will return one of the detailed
4433** [error codes] or [extended error codes]. ^The legacy behavior was that
4434** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
4435** and the application would have to make a second call to [sqlite3_reset()]
4436** in order to find the underlying cause of the problem. With the "v2" prepare
4437** interfaces, the underlying reason for the error is returned immediately.
4438** </li>
4440** <li>
4441** ^If the specific value bound to a [parameter | host parameter] in the
4442** WHERE clause might influence the choice of query plan for a statement,
4443** then the statement will be automatically recompiled, as if there had been
4444** a schema change, on the first [sqlite3_step()] call following any change
4445** to the [sqlite3_bind_text | bindings] of that [parameter].
4446** ^The specific value of a WHERE-clause [parameter] might influence the
4447** choice of query plan if the parameter is the left-hand side of a [LIKE]
4448** or [GLOB] operator or if the parameter is compared to an indexed column
4449** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled.
4450** </li>
4451** </ol>
4453** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
4454** the extra prepFlags parameter, which is a bit array consisting of zero or
4455** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The
4456** sqlite3_prepare_v2() interface works exactly the same as
4457** sqlite3_prepare_v3() with a zero prepFlags parameter.
4459SQLITE_API int sqlite3_prepare(
4460 sqlite3 *db, /* Database handle */
4461 const char *zSql, /* SQL statement, UTF-8 encoded */
4462 int nByte, /* Maximum length of zSql in bytes. */
4463 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
4464 const char **pzTail /* OUT: Pointer to unused portion of zSql */
4466SQLITE_API int sqlite3_prepare_v2(
4467 sqlite3 *db, /* Database handle */
4468 const char *zSql, /* SQL statement, UTF-8 encoded */
4469 int nByte, /* Maximum length of zSql in bytes. */
4470 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
4471 const char **pzTail /* OUT: Pointer to unused portion of zSql */
4473SQLITE_API int sqlite3_prepare_v3(
4474 sqlite3 *db, /* Database handle */
4475 const char *zSql, /* SQL statement, UTF-8 encoded */
4476 int nByte, /* Maximum length of zSql in bytes. */
4477 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
4478 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
4479 const char **pzTail /* OUT: Pointer to unused portion of zSql */
4481SQLITE_API int sqlite3_prepare16(
4482 sqlite3 *db, /* Database handle */
4483 const void *zSql, /* SQL statement, UTF-16 encoded */
4484 int nByte, /* Maximum length of zSql in bytes. */
4485 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
4486 const void **pzTail /* OUT: Pointer to unused portion of zSql */
4488SQLITE_API int sqlite3_prepare16_v2(
4489 sqlite3 *db, /* Database handle */
4490 const void *zSql, /* SQL statement, UTF-16 encoded */
4491 int nByte, /* Maximum length of zSql in bytes. */
4492 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
4493 const void **pzTail /* OUT: Pointer to unused portion of zSql */
4495SQLITE_API int sqlite3_prepare16_v3(
4496 sqlite3 *db, /* Database handle */
4497 const void *zSql, /* SQL statement, UTF-16 encoded */
4498 int nByte, /* Maximum length of zSql in bytes. */
4499 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
4500 sqlite3_stmt **ppStmt, /* OUT: Statement handle */
4501 const void **pzTail /* OUT: Pointer to unused portion of zSql */
4505** CAPI3REF: Retrieving Statement SQL
4506** METHOD: sqlite3_stmt
4508** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
4509** SQL text used to create [prepared statement] P if P was
4510** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
4511** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4512** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
4513** string containing the SQL text of prepared statement P with
4514** [bound parameters] expanded.
4515** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8
4516** string containing the normalized SQL text of prepared statement P. The
4517** semantics used to normalize a SQL statement are unspecified and subject
4518** to change. At a minimum, literal values will be replaced with suitable
4519** placeholders.
4521** ^(For example, if a prepared statement is created using the SQL
4522** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
4523** and parameter :xyz is unbound, then sqlite3_sql() will return
4524** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
4525** will return "SELECT 2345,NULL".)^
4527** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
4528** is available to hold the result, or if the result would exceed the
4529** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
4531** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
4532** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time
4533** option causes sqlite3_expanded_sql() to always return NULL.
4535** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P)
4536** are managed by SQLite and are automatically freed when the prepared
4537** statement is finalized.
4538** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
4539** is obtained from [sqlite3_malloc()] and must be freed by the application
4540** by passing it to [sqlite3_free()].
4542** ^The sqlite3_normalized_sql() interface is only available if
4543** the [SQLITE_ENABLE_NORMALIZE] compile-time option is defined.
4545SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
4546SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
4548SQLITE_API const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt);
4552** CAPI3REF: Determine If An SQL Statement Writes The Database
4553** METHOD: sqlite3_stmt
4555** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
4556** and only if the [prepared statement] X makes no direct changes to
4557** the content of the database file.
4559** Note that [application-defined SQL functions] or
4560** [virtual tables] might change the database indirectly as a side effect.
4561** ^(For example, if an application defines a function "eval()" that
4562** calls [sqlite3_exec()], then the following SQL statement would
4563** change the database file through side-effects:
4565** <blockquote><pre>
4566** SELECT eval('DELETE FROM t1') FROM t2;
4567** </pre></blockquote>
4569** But because the [SELECT] statement does not change the database file
4570** directly, sqlite3_stmt_readonly() would still return true.)^
4572** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
4573** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
4574** since the statements themselves do not actually modify the database but
4575** rather they control the timing of when other statements modify the
4576** database. ^The [ATTACH] and [DETACH] statements also cause
4577** sqlite3_stmt_readonly() to return true since, while those statements
4578** change the configuration of a database connection, they do not make
4579** changes to the content of the database files on disk.
4580** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
4581** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
4582** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
4583** sqlite3_stmt_readonly() returns false for those commands.
4585** ^This routine returns false if there is any possibility that the
4586** statement might change the database file. ^A false return does
4587** not guarantee that the statement will change the database file.
4588** ^For example, an UPDATE statement might have a WHERE clause that
4589** makes it a no-op, but the sqlite3_stmt_readonly() result would still
4590** be false. ^Similarly, a CREATE TABLE IF NOT EXISTS statement is a
4591** read-only no-op if the table already exists, but
4592** sqlite3_stmt_readonly() still returns false for such a statement.
4594** ^If prepared statement X is an [EXPLAIN] or [EXPLAIN QUERY PLAN]
4595** statement, then sqlite3_stmt_readonly(X) returns the same value as
4596** if the EXPLAIN or EXPLAIN QUERY PLAN prefix were omitted.
4598SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
4601** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement
4602** METHOD: sqlite3_stmt
4604** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the
4605** prepared statement S is an EXPLAIN statement, or 2 if the
4606** statement S is an EXPLAIN QUERY PLAN.
4607** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is
4608** an ordinary statement or a NULL pointer.
4610SQLITE_API int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt);
4613** CAPI3REF: Determine If A Prepared Statement Has Been Reset
4614** METHOD: sqlite3_stmt
4616** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
4617** [prepared statement] S has been stepped at least once using
4618** [sqlite3_step(S)] but has neither run to completion (returned
4619** [SQLITE_DONE] from [sqlite3_step(S)]) nor
4620** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S)
4621** interface returns false if S is a NULL pointer. If S is not a
4622** NULL pointer and is not a pointer to a valid [prepared statement]
4623** object, then the behavior is undefined and probably undesirable.
4625** This interface can be used in combination [sqlite3_next_stmt()]
4626** to locate all prepared statements associated with a database
4627** connection that are in need of being reset. This can be used,
4628** for example, in diagnostic routines to search for prepared
4629** statements that are holding a transaction open.
4631SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
4634** CAPI3REF: Dynamically Typed Value Object
4635** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
4637** SQLite uses the sqlite3_value object to represent all values
4638** that can be stored in a database table. SQLite uses dynamic typing
4639** for the values it stores. ^Values stored in sqlite3_value objects
4640** can be integers, floating point values, strings, BLOBs, or NULL.
4642** An sqlite3_value object may be either "protected" or "unprotected".
4643** Some interfaces require a protected sqlite3_value. Other interfaces
4644** will accept either a protected or an unprotected sqlite3_value.
4645** Every interface that accepts sqlite3_value arguments specifies
4646** whether or not it requires a protected sqlite3_value. The
4647** [sqlite3_value_dup()] interface can be used to construct a new
4648** protected sqlite3_value from an unprotected sqlite3_value.
4650** The terms "protected" and "unprotected" refer to whether or not
4651** a mutex is held. An internal mutex is held for a protected
4652** sqlite3_value object but no mutex is held for an unprotected
4653** sqlite3_value object. If SQLite is compiled to be single-threaded
4654** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
4655** or if SQLite is run in one of reduced mutex modes
4657** then there is no distinction between protected and unprotected
4658** sqlite3_value objects and they can be used interchangeably. However,
4659** for maximum code portability it is recommended that applications
4660** still make the distinction between protected and unprotected
4661** sqlite3_value objects even when not strictly required.
4663** ^The sqlite3_value objects that are passed as parameters into the
4664** implementation of [application-defined SQL functions] are protected.
4665** ^The sqlite3_value objects returned by [sqlite3_vtab_rhs_value()]
4666** are protected.
4667** ^The sqlite3_value object returned by
4668** [sqlite3_column_value()] is unprotected.
4669** Unprotected sqlite3_value objects may only be used as arguments
4670** to [sqlite3_result_value()], [sqlite3_bind_value()], and
4671** [sqlite3_value_dup()].
4672** The [sqlite3_value_blob | sqlite3_value_type()] family of
4673** interfaces require protected sqlite3_value objects.
4675typedef struct sqlite3_value sqlite3_value;
4678** CAPI3REF: SQL Function Context Object
4680** The context in which an SQL function executes is stored in an
4681** sqlite3_context object. ^A pointer to an sqlite3_context object
4682** is always first parameter to [application-defined SQL functions].
4683** The application-defined SQL function implementation will pass this
4684** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
4685** [sqlite3_aggregate_context()], [sqlite3_user_data()],
4686** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
4687** and/or [sqlite3_set_auxdata()].
4689typedef struct sqlite3_context sqlite3_context;
4692** CAPI3REF: Binding Values To Prepared Statements
4693** KEYWORDS: {host parameter} {host parameters} {host parameter name}
4694** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
4695** METHOD: sqlite3_stmt
4697** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
4698** literals may be replaced by a [parameter] that matches one of following
4699** templates:
4701** <ul>
4702** <li> ?
4703** <li> ?NNN
4704** <li> :VVV
4705** <li> @VVV
4706** <li> $VVV
4707** </ul>
4709** In the templates above, NNN represents an integer literal,
4710** and VVV represents an alphanumeric identifier.)^ ^The values of these
4711** parameters (also called "host parameter names" or "SQL parameters")
4712** can be set using the sqlite3_bind_*() routines defined here.
4714** ^The first argument to the sqlite3_bind_*() routines is always
4715** a pointer to the [sqlite3_stmt] object returned from
4716** [sqlite3_prepare_v2()] or its variants.
4718** ^The second argument is the index of the SQL parameter to be set.
4719** ^The leftmost SQL parameter has an index of 1. ^When the same named
4720** SQL parameter is used more than once, second and subsequent
4721** occurrences have the same index as the first occurrence.
4722** ^The index for named parameters can be looked up using the
4723** [sqlite3_bind_parameter_index()] API if desired. ^The index
4724** for "?NNN" parameters is the value of NNN.
4725** ^The NNN value must be between 1 and the [sqlite3_limit()]
4726** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766).
4728** ^The third argument is the value to bind to the parameter.
4729** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
4730** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
4731** is ignored and the end result is the same as sqlite3_bind_null().
4732** ^If the third parameter to sqlite3_bind_text() is not NULL, then
4733** it should be a pointer to well-formed UTF8 text.
4734** ^If the third parameter to sqlite3_bind_text16() is not NULL, then
4735** it should be a pointer to well-formed UTF16 text.
4736** ^If the third parameter to sqlite3_bind_text64() is not NULL, then
4737** it should be a pointer to a well-formed unicode string that is
4738** either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16
4739** otherwise.
4741** [[byte-order determination rules]] ^The byte-order of
4742** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF)
4743** found in first character, which is removed, or in the absence of a BOM
4744** the byte order is the native byte order of the host
4745** machine for sqlite3_bind_text16() or the byte order specified in
4746** the 6th parameter for sqlite3_bind_text64().)^
4747** ^If UTF16 input text contains invalid unicode
4748** characters, then SQLite might change those invalid characters
4749** into the unicode replacement character: U+FFFD.
4751** ^(In those routines that have a fourth argument, its value is the
4752** number of bytes in the parameter. To be clear: the value is the
4753** number of <u>bytes</u> in the value, not the number of characters.)^
4754** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
4755** is negative, then the length of the string is
4756** the number of bytes up to the first zero terminator.
4757** If the fourth parameter to sqlite3_bind_blob() is negative, then
4758** the behavior is undefined.
4759** If a non-negative fourth parameter is provided to sqlite3_bind_text()
4760** or sqlite3_bind_text16() or sqlite3_bind_text64() then
4761** that parameter must be the byte offset
4762** where the NUL terminator would occur assuming the string were NUL
4763** terminated. If any NUL characters occurs at byte offsets less than
4764** the value of the fourth parameter then the resulting string value will
4765** contain embedded NULs. The result of expressions involving strings
4766** with embedded NULs is undefined.
4768** ^The fifth argument to the BLOB and string binding interfaces controls
4769** or indicates the lifetime of the object referenced by the third parameter.
4770** These three options exist:
4771** ^ (1) A destructor to dispose of the BLOB or string after SQLite has finished
4772** with it may be passed. ^It is called to dispose of the BLOB or string even
4773** if the call to the bind API fails, except the destructor is not called if
4774** the third parameter is a NULL pointer or the fourth parameter is negative.
4775** ^ (2) The special constant, [SQLITE_STATIC], may be passsed to indicate that
4776** the application remains responsible for disposing of the object. ^In this
4777** case, the object and the provided pointer to it must remain valid until
4778** either the prepared statement is finalized or the same SQL parameter is
4779** bound to something else, whichever occurs sooner.
4780** ^ (3) The constant, [SQLITE_TRANSIENT], may be passed to indicate that the
4781** object is to be copied prior to the return from sqlite3_bind_*(). ^The
4782** object and pointer to it must remain valid until then. ^SQLite will then
4783** manage the lifetime of its private copy.
4785** ^The sixth argument to sqlite3_bind_text64() must be one of
4787** to specify the encoding of the text in the third parameter. If
4788** the sixth argument to sqlite3_bind_text64() is not one of the
4789** allowed values shown above, or if the text encoding is different
4790** from the encoding specified by the sixth parameter, then the behavior
4791** is undefined.
4793** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
4794** is filled with zeroes. ^A zeroblob uses a fixed amount of memory
4795** (just an integer to hold its size) while it is being processed.
4796** Zeroblobs are intended to serve as placeholders for BLOBs whose
4797** content is later written using
4798** [sqlite3_blob_open | incremental BLOB I/O] routines.
4799** ^A negative value for the zeroblob results in a zero-length BLOB.
4801** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
4802** [prepared statement] S to have an SQL value of NULL, but to also be
4803** associated with the pointer P of type T. ^D is either a NULL pointer or
4804** a pointer to a destructor function for P. ^SQLite will invoke the
4805** destructor D with a single argument of P when it is finished using
4806** P. The T parameter should be a static string, preferably a string
4807** literal. The sqlite3_bind_pointer() routine is part of the
4808** [pointer passing interface] added for SQLite 3.20.0.
4810** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
4811** for the [prepared statement] or with a prepared statement for which
4812** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
4813** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_()
4814** routine is passed a [prepared statement] that has been finalized, the
4815** result is undefined and probably harmful.
4817** ^Bindings are not cleared by the [sqlite3_reset()] routine.
4818** ^Unbound parameters are interpreted as NULL.
4820** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
4821** [error code] if anything goes wrong.
4822** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
4823** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
4825** ^[SQLITE_RANGE] is returned if the parameter
4826** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails.
4828** See also: [sqlite3_bind_parameter_count()],
4829** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
4831SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
4832SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
4833 void(*)(void*));
4834SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
4835SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
4836SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
4837SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
4838SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
4839SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
4840SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
4841 void(*)(void*), unsigned char encoding);
4842SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
4843SQLITE_API int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
4844SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
4845SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
4848** CAPI3REF: Number Of SQL Parameters
4849** METHOD: sqlite3_stmt
4851** ^This routine can be used to find the number of [SQL parameters]
4852** in a [prepared statement]. SQL parameters are tokens of the
4853** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
4854** placeholders for values that are [sqlite3_bind_blob | bound]
4855** to the parameters at a later time.
4857** ^(This routine actually returns the index of the largest (rightmost)
4858** parameter. For all forms except ?NNN, this will correspond to the
4859** number of unique parameters. If parameters of the ?NNN form are used,
4860** there may be gaps in the list.)^
4862** See also: [sqlite3_bind_blob|sqlite3_bind()],
4863** [sqlite3_bind_parameter_name()], and
4864** [sqlite3_bind_parameter_index()].
4866SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
4869** CAPI3REF: Name Of A Host Parameter
4870** METHOD: sqlite3_stmt
4872** ^The sqlite3_bind_parameter_name(P,N) interface returns
4873** the name of the N-th [SQL parameter] in the [prepared statement] P.
4874** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
4875** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
4876** respectively.
4877** In other words, the initial ":" or "$" or "@" or "?"
4878** is included as part of the name.)^
4879** ^Parameters of the form "?" without a following integer have no name
4880** and are referred to as "nameless" or "anonymous parameters".
4882** ^The first host parameter has an index of 1, not 0.
4884** ^If the value N is out of range or if the N-th parameter is
4885** nameless, then NULL is returned. ^The returned string is
4886** always in UTF-8 encoding even if the named parameter was
4887** originally specified as UTF-16 in [sqlite3_prepare16()],
4888** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
4890** See also: [sqlite3_bind_blob|sqlite3_bind()],
4891** [sqlite3_bind_parameter_count()], and
4892** [sqlite3_bind_parameter_index()].
4894SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
4897** CAPI3REF: Index Of A Parameter With A Given Name
4898** METHOD: sqlite3_stmt
4900** ^Return the index of an SQL parameter given its name. ^The
4901** index value returned is suitable for use as the second
4902** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero
4903** is returned if no matching parameter is found. ^The parameter
4904** name must be given in UTF-8 even if the original statement
4905** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
4906** [sqlite3_prepare16_v3()].
4908** See also: [sqlite3_bind_blob|sqlite3_bind()],
4909** [sqlite3_bind_parameter_count()], and
4910** [sqlite3_bind_parameter_name()].
4912SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
4915** CAPI3REF: Reset All Bindings On A Prepared Statement
4916** METHOD: sqlite3_stmt
4918** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
4919** the [sqlite3_bind_blob | bindings] on a [prepared statement].
4920** ^Use this routine to reset all host parameters to NULL.
4922SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
4925** CAPI3REF: Number Of Columns In A Result Set
4926** METHOD: sqlite3_stmt
4928** ^Return the number of columns in the result set returned by the
4929** [prepared statement]. ^If this routine returns 0, that means the
4930** [prepared statement] returns no data (for example an [UPDATE]).
4931** ^However, just because this routine returns a positive number does not
4932** mean that one or more rows of data will be returned. ^A SELECT statement
4933** will always have a positive sqlite3_column_count() but depending on the
4934** WHERE clause constraints and the table content, it might return no rows.
4936** See also: [sqlite3_data_count()]
4938SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
4941** CAPI3REF: Column Names In A Result Set
4942** METHOD: sqlite3_stmt
4944** ^These routines return the name assigned to a particular column
4945** in the result set of a [SELECT] statement. ^The sqlite3_column_name()
4946** interface returns a pointer to a zero-terminated UTF-8 string
4947** and sqlite3_column_name16() returns a pointer to a zero-terminated
4948** UTF-16 string. ^The first parameter is the [prepared statement]
4949** that implements the [SELECT] statement. ^The second parameter is the
4950** column number. ^The leftmost column is number 0.
4952** ^The returned string pointer is valid until either the [prepared statement]
4953** is destroyed by [sqlite3_finalize()] or until the statement is automatically
4954** reprepared by the first call to [sqlite3_step()] for a particular run
4955** or until the next call to
4956** sqlite3_column_name() or sqlite3_column_name16() on the same column.
4958** ^If sqlite3_malloc() fails during the processing of either routine
4959** (for example during a conversion from UTF-8 to UTF-16) then a
4960** NULL pointer is returned.
4962** ^The name of a result column is the value of the "AS" clause for
4963** that column, if there is an AS clause. If there is no AS clause
4964** then the name of the column is unspecified and may change from
4965** one release of SQLite to the next.
4967SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
4968SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
4971** CAPI3REF: Source Of Data In A Query Result
4972** METHOD: sqlite3_stmt
4974** ^These routines provide a means to determine the database, table, and
4975** table column that is the origin of a particular result column in
4976** [SELECT] statement.
4977** ^The name of the database or table or column can be returned as
4978** either a UTF-8 or UTF-16 string. ^The _database_ routines return
4979** the database name, the _table_ routines return the table name, and
4980** the origin_ routines return the column name.
4981** ^The returned string is valid until the [prepared statement] is destroyed
4982** using [sqlite3_finalize()] or until the statement is automatically
4983** reprepared by the first call to [sqlite3_step()] for a particular run
4984** or until the same information is requested
4985** again in a different encoding.
4987** ^The names returned are the original un-aliased names of the
4988** database, table, and column.
4990** ^The first argument to these interfaces is a [prepared statement].
4991** ^These functions return information about the Nth result column returned by
4992** the statement, where N is the second function argument.
4993** ^The left-most column is column 0 for these routines.
4995** ^If the Nth column returned by the statement is an expression or
4996** subquery and is not a column value, then all of these functions return
4997** NULL. ^These routines might also return NULL if a memory allocation error
4998** occurs. ^Otherwise, they return the name of the attached database, table,
4999** or column that query result column was extracted from.
5001** ^As with all other SQLite APIs, those whose names end with "16" return
5002** UTF-16 encoded strings and the other functions return UTF-8.
5004** ^These APIs are only available if the library was compiled with the
5005** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
5007** If two or more threads call one or more
5008** [sqlite3_column_database_name | column metadata interfaces]
5009** for the same [prepared statement] and result column
5010** at the same time then the results are undefined.
5012SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
5013SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
5014SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
5015SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
5016SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
5017SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
5020** CAPI3REF: Declared Datatype Of A Query Result
5021** METHOD: sqlite3_stmt
5023** ^(The first parameter is a [prepared statement].
5024** If this statement is a [SELECT] statement and the Nth column of the
5025** returned result set of that [SELECT] is a table column (not an
5026** expression or subquery) then the declared type of the table
5027** column is returned.)^ ^If the Nth column of the result set is an
5028** expression or subquery, then a NULL pointer is returned.
5029** ^The returned string is always UTF-8 encoded.
5031** ^(For example, given the database schema:
5035** and the following statement to be compiled:
5037** SELECT c1 + 1, c1 FROM t1;
5039** this routine would return the string "VARIANT" for the second result
5040** column (i==1), and a NULL pointer for the first result column (i==0).)^
5042** ^SQLite uses dynamic run-time typing. ^So just because a column
5043** is declared to contain a particular type does not mean that the
5044** data stored in that column is of the declared type. SQLite is
5045** strongly typed, but the typing is dynamic not static. ^Type
5046** is associated with individual values, not with the containers
5047** used to hold those values.
5049SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
5050SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
5053** CAPI3REF: Evaluate An SQL Statement
5054** METHOD: sqlite3_stmt
5056** After a [prepared statement] has been prepared using any of
5057** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
5058** or [sqlite3_prepare16_v3()] or one of the legacy
5059** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
5060** must be called one or more times to evaluate the statement.
5062** The details of the behavior of the sqlite3_step() interface depend
5063** on whether the statement was prepared using the newer "vX" interfaces
5064** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
5065** [sqlite3_prepare16_v2()] or the older legacy
5066** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the
5067** new "vX" interface is recommended for new applications but the legacy
5068** interface will continue to be supported.
5070** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
5072** ^With the "v2" interface, any of the other [result codes] or
5073** [extended result codes] might be returned as well.
5075** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
5076** database locks it needs to do its job. ^If the statement is a [COMMIT]
5077** or occurs outside of an explicit transaction, then you can retry the
5078** statement. If the statement is not a [COMMIT] and occurs within an
5079** explicit transaction then you should rollback the transaction before
5080** continuing.
5082** ^[SQLITE_DONE] means that the statement has finished executing
5083** successfully. sqlite3_step() should not be called again on this virtual
5084** machine without first calling [sqlite3_reset()] to reset the virtual
5085** machine back to its initial state.
5087** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
5088** is returned each time a new row of data is ready for processing by the
5089** caller. The values may be accessed using the [column access functions].
5090** sqlite3_step() is called again to retrieve the next row of data.
5092** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
5093** violation) has occurred. sqlite3_step() should not be called again on
5094** the VM. More information may be found by calling [sqlite3_errmsg()].
5095** ^With the legacy interface, a more specific error code (for example,
5097** can be obtained by calling [sqlite3_reset()] on the
5098** [prepared statement]. ^In the "v2" interface,
5099** the more specific error code is returned directly by sqlite3_step().
5101** [SQLITE_MISUSE] means that the this routine was called inappropriately.
5102** Perhaps it was called on a [prepared statement] that has
5103** already been [sqlite3_finalize | finalized] or on one that had
5104** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could
5105** be the case that the same database connection is being used by two or
5106** more threads at the same moment in time.
5108** For all versions of SQLite up to and including, a call to
5109** [sqlite3_reset()] was required after sqlite3_step() returned anything
5110** other than [SQLITE_ROW] before any subsequent invocation of
5111** sqlite3_step(). Failure to reset the prepared statement using
5112** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
5113** sqlite3_step(). But after [version] ([dateof:],
5114** sqlite3_step() began
5115** calling [sqlite3_reset()] automatically in this circumstance rather
5116** than returning [SQLITE_MISUSE]. This is not considered a compatibility
5117** break because any application that ever receives an SQLITE_MISUSE error
5118** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option
5119** can be used to restore the legacy behavior.
5121** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
5122** API always returns a generic error code, [SQLITE_ERROR], following any
5123** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call
5124** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
5125** specific [error codes] that better describes the error.
5126** We admit that this is a goofy design. The problem has been fixed
5127** with the "v2" interface. If you prepare all of your SQL statements
5128** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
5129** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
5130** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
5131** then the more specific [error codes] are returned directly
5132** by sqlite3_step(). The use of the "vX" interfaces is recommended.
5134SQLITE_API int sqlite3_step(sqlite3_stmt*);
5137** CAPI3REF: Number of columns in a result set
5138** METHOD: sqlite3_stmt
5140** ^The sqlite3_data_count(P) interface returns the number of columns in the
5141** current row of the result set of [prepared statement] P.
5142** ^If prepared statement P does not have results ready to return
5143** (via calls to the [sqlite3_column_int | sqlite3_column()] family of
5144** interfaces) then sqlite3_data_count(P) returns 0.
5145** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
5146** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
5147** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P)
5148** will return non-zero if previous call to [sqlite3_step](P) returned
5149** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
5150** where it always returns zero since each step of that multi-step
5151** pragma returns 0 columns of data.
5153** See also: [sqlite3_column_count()]
5155SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
5158** CAPI3REF: Fundamental Datatypes
5161** ^(Every value in SQLite has one of five fundamental datatypes:
5163** <ul>
5164** <li> 64-bit signed integer
5165** <li> 64-bit IEEE floating point number
5166** <li> string
5167** <li> BLOB
5168** <li> NULL
5169** </ul>)^
5171** These constants are codes for each of those types.
5173** Note that the SQLITE_TEXT constant was also used in SQLite version 2
5174** for a completely different meaning. Software that links against both
5175** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
5178#define SQLITE_INTEGER 1
5179#define SQLITE_FLOAT 2
5180#define SQLITE_BLOB 4
5181#define SQLITE_NULL 5
5182#ifdef SQLITE_TEXT
5183# undef SQLITE_TEXT
5185# define SQLITE_TEXT 3
5187#define SQLITE3_TEXT 3
5190** CAPI3REF: Result Values From A Query
5191** KEYWORDS: {column access functions}
5192** METHOD: sqlite3_stmt
5194** <b>Summary:</b>
5195** <blockquote><table border=0 cellpadding=0 cellspacing=0>
5196** <tr><td><b>sqlite3_column_blob</b><td>&rarr;<td>BLOB result
5197** <tr><td><b>sqlite3_column_double</b><td>&rarr;<td>REAL result
5198** <tr><td><b>sqlite3_column_int</b><td>&rarr;<td>32-bit INTEGER result
5199** <tr><td><b>sqlite3_column_int64</b><td>&rarr;<td>64-bit INTEGER result
5200** <tr><td><b>sqlite3_column_text</b><td>&rarr;<td>UTF-8 TEXT result
5201** <tr><td><b>sqlite3_column_text16</b><td>&rarr;<td>UTF-16 TEXT result
5202** <tr><td><b>sqlite3_column_value</b><td>&rarr;<td>The result as an
5203** [sqlite3_value|unprotected sqlite3_value] object.
5204** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
5205** <tr><td><b>sqlite3_column_bytes</b><td>&rarr;<td>Size of a BLOB
5206** or a UTF-8 TEXT result in bytes
5207** <tr><td><b>sqlite3_column_bytes16&nbsp;&nbsp;</b>
5208** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
5209** TEXT in bytes
5210** <tr><td><b>sqlite3_column_type</b><td>&rarr;<td>Default
5211** datatype of the result
5212** </table></blockquote>
5214** <b>Details:</b>
5216** ^These routines return information about a single column of the current
5217** result row of a query. ^In every case the first argument is a pointer
5218** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
5219** that was returned from [sqlite3_prepare_v2()] or one of its variants)
5220** and the second argument is the index of the column for which information
5221** should be returned. ^The leftmost column of the result set has the index 0.
5222** ^The number of columns in the result can be determined using
5223** [sqlite3_column_count()].
5225** If the SQL statement does not currently point to a valid row, or if the
5226** column index is out of range, the result is undefined.
5227** These routines may only be called when the most recent call to
5228** [sqlite3_step()] has returned [SQLITE_ROW] and neither
5229** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
5230** If any of these routines are called after [sqlite3_reset()] or
5231** [sqlite3_finalize()] or after [sqlite3_step()] has returned
5232** something other than [SQLITE_ROW], the results are undefined.
5233** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
5234** are called from a different thread while any of these routines
5235** are pending, then the results are undefined.
5237** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
5238** each return the value of a result column in a specific data format. If
5239** the result column is not initially in the requested format (for example,
5240** if the query returns an integer but the sqlite3_column_text() interface
5241** is used to extract the value) then an automatic type conversion is performed.
5243** ^The sqlite3_column_type() routine returns the
5244** [SQLITE_INTEGER | datatype code] for the initial data type
5245** of the result column. ^The returned value is one of [SQLITE_INTEGER],
5247** The return value of sqlite3_column_type() can be used to decide which
5248** of the first six interface should be used to extract the column value.
5249** The value returned by sqlite3_column_type() is only meaningful if no
5250** automatic type conversions have occurred for the value in question.
5251** After a type conversion, the result of calling sqlite3_column_type()
5252** is undefined, though harmless. Future
5253** versions of SQLite may change the behavior of sqlite3_column_type()
5254** following a type conversion.
5256** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
5257** or sqlite3_column_bytes16() interfaces can be used to determine the size
5258** of that BLOB or string.
5260** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
5261** routine returns the number of bytes in that BLOB or string.
5262** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
5263** the string to UTF-8 and then returns the number of bytes.
5264** ^If the result is a numeric value then sqlite3_column_bytes() uses
5265** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
5266** the number of bytes in that string.
5267** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
5269** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
5270** routine returns the number of bytes in that BLOB or string.
5271** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
5272** the string to UTF-16 and then returns the number of bytes.
5273** ^If the result is a numeric value then sqlite3_column_bytes16() uses
5274** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
5275** the number of bytes in that string.
5276** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
5278** ^The values returned by [sqlite3_column_bytes()] and
5279** [sqlite3_column_bytes16()] do not include the zero terminators at the end
5280** of the string. ^For clarity: the values returned by
5281** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
5282** bytes in the string, not the number of characters.
5284** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
5285** even empty strings, are always zero-terminated. ^The return
5286** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
5288** ^Strings returned by sqlite3_column_text16() always have the endianness
5289** which is native to the platform, regardless of the text encoding set
5290** for the database.
5292** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
5293** [unprotected sqlite3_value] object. In a multithreaded environment,
5294** an unprotected sqlite3_value object may only be used safely with
5295** [sqlite3_bind_value()] and [sqlite3_result_value()].
5296** If the [unprotected sqlite3_value] object returned by
5297** [sqlite3_column_value()] is used in any other way, including calls
5298** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
5299** or [sqlite3_value_bytes()], the behavior is not threadsafe.
5300** Hence, the sqlite3_column_value() interface
5301** is normally only useful within the implementation of
5302** [application-defined SQL functions] or [virtual tables], not within
5303** top-level application code.
5305** These routines may attempt to convert the datatype of the result.
5306** ^For example, if the internal representation is FLOAT and a text result
5307** is requested, [sqlite3_snprintf()] is used internally to perform the
5308** conversion automatically. ^(The following table details the conversions
5309** that are applied:
5311** <blockquote>
5312** <table border="1">
5313** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion
5315** <tr><td> NULL <td> INTEGER <td> Result is 0
5316** <tr><td> NULL <td> FLOAT <td> Result is 0.0
5317** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer
5318** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer
5319** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
5320** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
5321** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
5322** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER
5323** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
5324** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB
5325** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER
5326** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL
5327** <tr><td> TEXT <td> BLOB <td> No change
5328** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER
5329** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL
5330** <tr><td> BLOB <td> TEXT <td> [CAST] to TEXT, ensure zero terminator
5331** </table>
5332** </blockquote>)^
5334** Note that when type conversions occur, pointers returned by prior
5335** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
5336** sqlite3_column_text16() may be invalidated.
5337** Type conversions and pointer invalidations might occur
5338** in the following cases:
5340** <ul>
5341** <li> The initial content is a BLOB and sqlite3_column_text() or
5342** sqlite3_column_text16() is called. A zero-terminator might
5343** need to be added to the string.</li>
5344** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
5345** sqlite3_column_text16() is called. The content must be converted
5346** to UTF-16.</li>
5347** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
5348** sqlite3_column_text() is called. The content must be converted
5349** to UTF-8.</li>
5350** </ul>
5352** ^Conversions between UTF-16be and UTF-16le are always done in place and do
5353** not invalidate a prior pointer, though of course the content of the buffer
5354** that the prior pointer references will have been modified. Other kinds
5355** of conversion are done in place when it is possible, but sometimes they
5356** are not possible and in those cases prior pointers are invalidated.
5358** The safest policy is to invoke these routines
5359** in one of the following ways:
5361** <ul>
5362** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
5363** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
5364** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
5365** </ul>
5367** In other words, you should call sqlite3_column_text(),
5368** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
5369** into the desired format, then invoke sqlite3_column_bytes() or
5370** sqlite3_column_bytes16() to find the size of the result. Do not mix calls
5371** to sqlite3_column_text() or sqlite3_column_blob() with calls to
5372** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
5373** with calls to sqlite3_column_bytes().
5375** ^The pointers returned are valid until a type conversion occurs as
5376** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
5377** [sqlite3_finalize()] is called. ^The memory space used to hold strings
5378** and BLOBs is freed automatically. Do not pass the pointers returned
5379** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
5380** [sqlite3_free()].
5382** As long as the input parameters are correct, these routines will only
5383** fail if an out-of-memory error occurs during a format conversion.
5384** Only the following subset of interfaces are subject to out-of-memory
5385** errors:
5387** <ul>
5388** <li> sqlite3_column_blob()
5389** <li> sqlite3_column_text()
5390** <li> sqlite3_column_text16()
5391** <li> sqlite3_column_bytes()
5392** <li> sqlite3_column_bytes16()
5393** </ul>
5395** If an out-of-memory error occurs, then the return value from these
5396** routines is the same as if the column had contained an SQL NULL value.
5397** Valid SQL NULL returns can be distinguished from out-of-memory errors
5398** by invoking the [sqlite3_errcode()] immediately after the suspect
5399** return value is obtained and before any
5400** other SQLite interface is called on the same [database connection].
5402SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
5403SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
5404SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
5405SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
5406SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
5407SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
5408SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
5409SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
5410SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
5411SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
5414** CAPI3REF: Destroy A Prepared Statement Object
5415** DESTRUCTOR: sqlite3_stmt
5417** ^The sqlite3_finalize() function is called to delete a [prepared statement].
5418** ^If the most recent evaluation of the statement encountered no errors
5419** or if the statement is never been evaluated, then sqlite3_finalize() returns
5420** SQLITE_OK. ^If the most recent evaluation of statement S failed, then
5421** sqlite3_finalize(S) returns the appropriate [error code] or
5422** [extended error code].
5424** ^The sqlite3_finalize(S) routine can be called at any point during
5425** the life cycle of [prepared statement] S:
5426** before statement S is ever evaluated, after
5427** one or more calls to [sqlite3_reset()], or after any call
5428** to [sqlite3_step()] regardless of whether or not the statement has
5429** completed execution.
5431** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
5433** The application must finalize every [prepared statement] in order to avoid
5434** resource leaks. It is a grievous error for the application to try to use
5435** a prepared statement after it has been finalized. Any use of a prepared
5436** statement after it has been finalized can result in undefined and
5437** undesirable behavior such as segfaults and heap corruption.
5439SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
5442** CAPI3REF: Reset A Prepared Statement Object
5443** METHOD: sqlite3_stmt
5445** The sqlite3_reset() function is called to reset a [prepared statement]
5446** object back to its initial state, ready to be re-executed.
5447** ^Any SQL statement variables that had values bound to them using
5448** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
5449** Use [sqlite3_clear_bindings()] to reset the bindings.
5451** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
5452** back to the beginning of its program.
5454** ^If the most recent call to [sqlite3_step(S)] for the
5455** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
5456** or if [sqlite3_step(S)] has never before been called on S,
5457** then [sqlite3_reset(S)] returns [SQLITE_OK].
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].
5463** ^The [sqlite3_reset(S)] interface does not change the values
5464** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
5466SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
5469** CAPI3REF: Create Or Redefine SQL Functions
5470** KEYWORDS: {function creation routines}
5471** METHOD: sqlite3
5473** ^These functions (collectively known as "function creation routines")
5474** are used to add SQL functions or aggregates or to redefine the behavior
5475** of existing SQL functions or aggregates. The only differences between
5476** the three "sqlite3_create_function*" routines are the text encoding
5477** expected for the second parameter (the name of the function being
5478** created) and the presence or absence of a destructor callback for
5479** the application data pointer. Function sqlite3_create_window_function()
5480** is similar, but allows the user to supply the extra callback functions
5481** needed by [aggregate window functions].
5483** ^The first parameter is the [database connection] to which the SQL
5484** function is to be added. ^If an application uses more than one database
5485** connection then application-defined SQL functions must be added
5486** to each database connection separately.
5488** ^The second parameter is the name of the SQL function to be created or
5489** redefined. ^The length of the name is limited to 255 bytes in a UTF-8
5490** representation, exclusive of the zero-terminator. ^Note that the name
5491** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
5492** ^Any attempt to create a function with a longer name
5493** will result in [SQLITE_MISUSE] being returned.
5495** ^The third parameter (nArg)
5496** is the number of arguments that the SQL function or
5497** aggregate takes. ^If this parameter is -1, then the SQL function or
5498** aggregate may take any number of arguments between 0 and the limit
5499** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third
5500** parameter is less than -1 or greater than 127 then the behavior is
5501** undefined.
5503** ^The fourth parameter, eTextRep, specifies what
5504** [SQLITE_UTF8 | text encoding] this SQL function prefers for
5505** its parameters. The application should set this parameter to
5506** [SQLITE_UTF16LE] if the function implementation invokes
5507** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
5508** implementation invokes [sqlite3_value_text16be()] on an input, or
5509** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
5510** otherwise. ^The same SQL function may be registered multiple times using
5511** different preferred text encodings, with different implementations for
5512** each encoding.
5513** ^When multiple implementations of the same function are available, SQLite
5514** will pick the one that involves the least amount of data conversion.
5516** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
5517** to signal that the function will always return the same result given
5518** the same inputs within a single SQL statement. Most SQL functions are
5519** deterministic. The built-in [random()] SQL function is an example of a
5520** function that is not deterministic. The SQLite query planner is able to
5521** perform additional optimizations on deterministic functions, so use
5522** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
5524** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY]
5525** flag, which if present prevents the function from being invoked from
5526** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions,
5527** index expressions, or the WHERE clause of partial indexes.
5529** For best security, the [SQLITE_DIRECTONLY] flag is recommended for
5530** all application-defined SQL functions that do not need to be
5531** used inside of triggers, view, CHECK constraints, or other elements of
5532** the database schema. This flags is especially recommended for SQL
5533** functions that have side effects or reveal internal application state.
5534** Without this flag, an attacker might be able to modify the schema of
5535** a database file to include invocations of the function with parameters
5536** chosen by the attacker, which the application will then execute when
5537** the database file is opened and read.
5539** ^(The fifth parameter is an arbitrary pointer. The implementation of the
5540** function can gain access to this pointer using [sqlite3_user_data()].)^
5542** ^The sixth, seventh and eighth parameters passed to the three
5543** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are
5544** pointers to C-language functions that implement the SQL function or
5545** aggregate. ^A scalar SQL function requires an implementation of the xFunc
5546** callback only; NULL pointers must be passed as the xStep and xFinal
5547** parameters. ^An aggregate SQL function requires an implementation of xStep
5548** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
5549** SQL function or aggregate, pass NULL pointers for all three function
5550** callbacks.
5552** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue
5553** and xInverse) passed to sqlite3_create_window_function are pointers to
5554** C-language callbacks that implement the new function. xStep and xFinal
5555** must both be non-NULL. xValue and xInverse may either both be NULL, in
5556** which case a regular aggregate function is created, or must both be
5557** non-NULL, in which case the new function may be used as either an aggregate
5558** or aggregate window function. More details regarding the implementation
5559** of aggregate window functions are
5560** [user-defined window functions|available here].
5562** ^(If the final parameter to sqlite3_create_function_v2() or
5563** sqlite3_create_window_function() is not NULL, then it is destructor for
5564** the application data pointer. The destructor is invoked when the function
5565** is deleted, either by being overloaded or when the database connection
5566** closes.)^ ^The destructor is also invoked if the call to
5567** sqlite3_create_function_v2() fails. ^When the destructor callback is
5568** invoked, it is passed a single argument which is a copy of the application
5569** data pointer which was the fifth parameter to sqlite3_create_function_v2().
5571** ^It is permitted to register multiple implementations of the same
5572** functions with the same name but with either differing numbers of
5573** arguments or differing preferred text encodings. ^SQLite will use
5574** the implementation that most closely matches the way in which the
5575** SQL function is used. ^A function implementation with a non-negative
5576** nArg parameter is a better match than a function implementation with
5577** a negative nArg. ^A function where the preferred text encoding
5578** matches the database encoding is a better
5579** match than a function where the encoding is different.
5580** ^A function where the encoding difference is between UTF16le and UTF16be
5581** is a closer match than a function where the encoding difference is
5582** between UTF8 and UTF16.
5584** ^Built-in functions may be overloaded by new application-defined functions.
5586** ^An application-defined function is permitted to call other
5587** SQLite interfaces. However, such calls must not
5588** close the database connection nor finalize or reset the prepared
5589** statement in which the function is running.
5591SQLITE_API int sqlite3_create_function(
5592 sqlite3 *db,
5593 const char *zFunctionName,
5594 int nArg,
5595 int eTextRep,
5596 void *pApp,
5597 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
5598 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5599 void (*xFinal)(sqlite3_context*)
5601SQLITE_API int sqlite3_create_function16(
5602 sqlite3 *db,
5603 const void *zFunctionName,
5604 int nArg,
5605 int eTextRep,
5606 void *pApp,
5607 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
5608 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5609 void (*xFinal)(sqlite3_context*)
5611SQLITE_API int sqlite3_create_function_v2(
5612 sqlite3 *db,
5613 const char *zFunctionName,
5614 int nArg,
5615 int eTextRep,
5616 void *pApp,
5617 void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
5618 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5619 void (*xFinal)(sqlite3_context*),
5620 void(*xDestroy)(void*)
5622SQLITE_API int sqlite3_create_window_function(
5623 sqlite3 *db,
5624 const char *zFunctionName,
5625 int nArg,
5626 int eTextRep,
5627 void *pApp,
5628 void (*xStep)(sqlite3_context*,int,sqlite3_value**),
5629 void (*xFinal)(sqlite3_context*),
5630 void (*xValue)(sqlite3_context*),
5631 void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
5632 void(*xDestroy)(void*)
5636** CAPI3REF: Text Encodings
5638** These constant define integer codes that represent the various
5639** text encodings supported by SQLite.
5641#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */
5642#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */
5643#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */
5644#define SQLITE_UTF16 4 /* Use native byte order */
5645#define SQLITE_ANY 5 /* Deprecated */
5646#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
5649** CAPI3REF: Function Flags
5651** These constants may be ORed together with the
5652** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
5653** to [sqlite3_create_function()], [sqlite3_create_function16()], or
5654** [sqlite3_create_function_v2()].
5656** <dl>
5658** The SQLITE_DETERMINISTIC flag means that the new function always gives
5659** the same output when the input parameters are the same.
5660** The [abs|abs() function] is deterministic, for example, but
5661** [randomblob|randomblob()] is not. Functions must
5662** be deterministic in order to be used in certain contexts such as
5663** with the WHERE clause of [partial indexes] or in [generated columns].
5664** SQLite might also optimize deterministic functions by factoring them
5665** out of inner loops.
5666** </dd>
5669** The SQLITE_DIRECTONLY flag means that the function may only be invoked
5670** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in
5671** schema structures such as [CHECK constraints], [DEFAULT clauses],
5672** [expression indexes], [partial indexes], or [generated columns].
5673** The SQLITE_DIRECTONLY flags is a security feature which is recommended
5674** for all [application-defined SQL functions], and especially for functions
5675** that have side-effects or that could potentially leak sensitive
5676** information.
5677** </dd>
5680** The SQLITE_INNOCUOUS flag means that the function is unlikely
5681** to cause problems even if misused. An innocuous function should have
5682** no side effects and should not depend on any values other than its
5683** input parameters. The [abs|abs() function] is an example of an
5684** innocuous function.
5685** The [load_extension() SQL function] is not innocuous because of its
5686** side effects.
5687** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not
5688** exactly the same. The [random|random() function] is an example of a
5689** function that is innocuous but not deterministic.
5690** <p>Some heightened security settings
5691** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF])
5692** disable the use of SQL functions inside views and triggers and in
5693** schema structures such as [CHECK constraints], [DEFAULT clauses],
5694** [expression indexes], [partial indexes], and [generated columns] unless
5695** the function is tagged with SQLITE_INNOCUOUS. Most built-in functions
5696** are innocuous. Developers are advised to avoid using the
5697** SQLITE_INNOCUOUS flag for application-defined functions unless the
5698** function has been carefully audited and found to be free of potentially
5699** security-adverse side-effects and information-leaks.
5700** </dd>
5702** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd>
5703** The SQLITE_SUBTYPE flag indicates to SQLite that a function may call
5704** [sqlite3_value_subtype()] to inspect the sub-types of its arguments.
5705** Specifying this flag makes no difference for scalar or aggregate user
5706** functions. However, if it is not specified for a user-defined window
5707** function, then any sub-types belonging to arguments passed to the window
5708** function may be discarded before the window function is called (i.e.
5709** sqlite3_value_subtype() will always return 0).
5710** </dd>
5711** </dl>
5713#define SQLITE_DETERMINISTIC 0x000000800
5714#define SQLITE_DIRECTONLY 0x000080000
5715#define SQLITE_SUBTYPE 0x000100000
5716#define SQLITE_INNOCUOUS 0x000200000
5719** CAPI3REF: Deprecated Functions
5722** These functions are [deprecated]. In order to maintain
5723** backwards compatibility with older code, these functions continue
5724** to be supported. However, new applications should avoid
5725** the use of these functions. To encourage programmers to avoid
5726** these functions, we will not explain what they do.
5729SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
5730SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
5731SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
5732SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
5733SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
5734SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
5735 void*,sqlite3_int64);
5739** CAPI3REF: Obtaining SQL Values
5740** METHOD: sqlite3_value
5742** <b>Summary:</b>
5743** <blockquote><table border=0 cellpadding=0 cellspacing=0>
5744** <tr><td><b>sqlite3_value_blob</b><td>&rarr;<td>BLOB value
5745** <tr><td><b>sqlite3_value_double</b><td>&rarr;<td>REAL value
5746** <tr><td><b>sqlite3_value_int</b><td>&rarr;<td>32-bit INTEGER value
5747** <tr><td><b>sqlite3_value_int64</b><td>&rarr;<td>64-bit INTEGER value
5748** <tr><td><b>sqlite3_value_pointer</b><td>&rarr;<td>Pointer value
5749** <tr><td><b>sqlite3_value_text</b><td>&rarr;<td>UTF-8 TEXT value
5750** <tr><td><b>sqlite3_value_text16</b><td>&rarr;<td>UTF-16 TEXT value in
5751** the native byteorder
5752** <tr><td><b>sqlite3_value_text16be</b><td>&rarr;<td>UTF-16be TEXT value
5753** <tr><td><b>sqlite3_value_text16le</b><td>&rarr;<td>UTF-16le TEXT value
5754** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
5755** <tr><td><b>sqlite3_value_bytes</b><td>&rarr;<td>Size of a BLOB
5756** or a UTF-8 TEXT in bytes
5757** <tr><td><b>sqlite3_value_bytes16&nbsp;&nbsp;</b>
5758** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
5759** TEXT in bytes
5760** <tr><td><b>sqlite3_value_type</b><td>&rarr;<td>Default
5761** datatype of the value
5762** <tr><td><b>sqlite3_value_numeric_type&nbsp;&nbsp;</b>
5763** <td>&rarr;&nbsp;&nbsp;<td>Best numeric datatype of the value
5764** <tr><td><b>sqlite3_value_nochange&nbsp;&nbsp;</b>
5765** <td>&rarr;&nbsp;&nbsp;<td>True if the column is unchanged in an UPDATE
5766** against a virtual table.
5767** <tr><td><b>sqlite3_value_frombind&nbsp;&nbsp;</b>
5768** <td>&rarr;&nbsp;&nbsp;<td>True if value originated from a [bound parameter]
5769** </table></blockquote>
5771** <b>Details:</b>
5773** These routines extract type, size, and content information from
5774** [protected sqlite3_value] objects. Protected sqlite3_value objects
5775** are used to pass parameter information into the functions that
5776** implement [application-defined SQL functions] and [virtual tables].
5778** These routines work only with [protected sqlite3_value] objects.
5779** Any attempt to use these routines on an [unprotected sqlite3_value]
5780** is not threadsafe.
5782** ^These routines work just like the corresponding [column access functions]
5783** except that these routines take a single [protected sqlite3_value] object
5784** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
5786** ^The sqlite3_value_text16() interface extracts a UTF-16 string
5787** in the native byte-order of the host machine. ^The
5788** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
5789** extract UTF-16 strings as big-endian and little-endian respectively.
5791** ^If [sqlite3_value] object V was initialized
5792** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
5793** and if X and Y are strings that compare equal according to strcmp(X,Y),
5794** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise,
5795** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
5796** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
5798** ^(The sqlite3_value_type(V) interface returns the
5799** [SQLITE_INTEGER | datatype code] for the initial datatype of the
5800** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
5802** Other interfaces might change the datatype for an sqlite3_value object.
5803** For example, if the datatype is initially SQLITE_INTEGER and
5804** sqlite3_value_text(V) is called to extract a text value for that
5805** integer, then subsequent calls to sqlite3_value_type(V) might return
5806** SQLITE_TEXT. Whether or not a persistent internal datatype conversion
5807** occurs is undefined and may change from one release of SQLite to the next.
5809** ^(The sqlite3_value_numeric_type() interface attempts to apply
5810** numeric affinity to the value. This means that an attempt is
5811** made to convert the value to an integer or floating point. If
5812** such a conversion is possible without loss of information (in other
5813** words, if the value is a string that looks like a number)
5814** then the conversion is performed. Otherwise no conversion occurs.
5815** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
5817** ^Within the [xUpdate] method of a [virtual table], the
5818** sqlite3_value_nochange(X) interface returns true if and only if
5819** the column corresponding to X is unchanged by the UPDATE operation
5820** that the xUpdate method call was invoked to implement and if
5821** and the prior [xColumn] method call that was invoked to extracted
5822** the value for that column returned without setting a result (probably
5823** because it queried [sqlite3_vtab_nochange()] and found that the column
5824** was unchanging). ^Within an [xUpdate] method, any value for which
5825** sqlite3_value_nochange(X) is true will in all other respects appear
5826** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other
5827** than within an [xUpdate] method call for an UPDATE statement, then
5828** the return value is arbitrary and meaningless.
5830** ^The sqlite3_value_frombind(X) interface returns non-zero if the
5831** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()]
5832** interfaces. ^If X comes from an SQL literal value, or a table column,
5833** or an expression, then sqlite3_value_frombind(X) returns zero.
5835** Please pay particular attention to the fact that the pointer returned
5836** from [sqlite3_value_blob()], [sqlite3_value_text()], or
5837** [sqlite3_value_text16()] can be invalidated by a subsequent call to
5838** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
5839** or [sqlite3_value_text16()].
5841** These routines must be called from the same thread as
5842** the SQL function that supplied the [sqlite3_value*] parameters.
5844** As long as the input parameter is correct, these routines can only
5845** fail if an out-of-memory error occurs during a format conversion.
5846** Only the following subset of interfaces are subject to out-of-memory
5847** errors:
5849** <ul>
5850** <li> sqlite3_value_blob()
5851** <li> sqlite3_value_text()
5852** <li> sqlite3_value_text16()
5853** <li> sqlite3_value_text16le()
5854** <li> sqlite3_value_text16be()
5855** <li> sqlite3_value_bytes()
5856** <li> sqlite3_value_bytes16()
5857** </ul>
5859** If an out-of-memory error occurs, then the return value from these
5860** routines is the same as if the column had contained an SQL NULL value.
5861** Valid SQL NULL returns can be distinguished from out-of-memory errors
5862** by invoking the [sqlite3_errcode()] immediately after the suspect
5863** return value is obtained and before any
5864** other SQLite interface is called on the same [database connection].
5866SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
5867SQLITE_API double sqlite3_value_double(sqlite3_value*);
5868SQLITE_API int sqlite3_value_int(sqlite3_value*);
5869SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
5870SQLITE_API void *sqlite3_value_pointer(sqlite3_value*, const char*);
5871SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
5872SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
5873SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
5874SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
5875SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
5876SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
5877SQLITE_API int sqlite3_value_type(sqlite3_value*);
5878SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
5879SQLITE_API int sqlite3_value_nochange(sqlite3_value*);
5880SQLITE_API int sqlite3_value_frombind(sqlite3_value*);
5883** CAPI3REF: Finding The Subtype Of SQL Values
5884** METHOD: sqlite3_value
5886** The sqlite3_value_subtype(V) function returns the subtype for
5887** an [application-defined SQL function] argument V. The subtype
5888** information can be used to pass a limited amount of context from
5889** one SQL function to another. Use the [sqlite3_result_subtype()]
5890** routine to set the subtype for the return value of an SQL function.
5892SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*);
5895** CAPI3REF: Copy And Free SQL Values
5896** METHOD: sqlite3_value
5898** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
5899** object D and returns a pointer to that copy. ^The [sqlite3_value] returned
5900** is a [protected sqlite3_value] object even if the input is not.
5901** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
5902** memory allocation fails. ^If V is a [pointer value], then the result
5903** of sqlite3_value_dup(V) is a NULL value.
5905** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
5906** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer
5907** then sqlite3_value_free(V) is a harmless no-op.
5909SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
5910SQLITE_API void sqlite3_value_free(sqlite3_value*);
5913** CAPI3REF: Obtain Aggregate Function Context
5914** METHOD: sqlite3_context
5916** Implementations of aggregate SQL functions use this
5917** routine to allocate memory for storing their state.
5919** ^The first time the sqlite3_aggregate_context(C,N) routine is called
5920** for a particular aggregate function, SQLite allocates
5921** N bytes of memory, zeroes out that memory, and returns a pointer
5922** to the new memory. ^On second and subsequent calls to
5923** sqlite3_aggregate_context() for the same aggregate function instance,
5924** the same buffer is returned. Sqlite3_aggregate_context() is normally
5925** called once for each invocation of the xStep callback and then one
5926** last time when the xFinal callback is invoked. ^(When no rows match
5927** an aggregate query, the xStep() callback of the aggregate function
5928** implementation is never called and xFinal() is called exactly once.
5929** In those cases, sqlite3_aggregate_context() might be called for the
5930** first time from within xFinal().)^
5932** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
5933** when first called if N is less than or equal to zero or if a memory
5934** allocate error occurs.
5936** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
5937** determined by the N parameter on first successful call. Changing the
5938** value of N in any subsequent call to sqlite3_aggregate_context() within
5939** the same aggregate function instance will not resize the memory
5940** allocation.)^ Within the xFinal callback, it is customary to set
5941** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
5942** pointless memory allocations occur.
5944** ^SQLite automatically frees the memory allocated by
5945** sqlite3_aggregate_context() when the aggregate query concludes.
5947** The first parameter must be a copy of the
5948** [sqlite3_context | SQL function context] that is the first parameter
5949** to the xStep or xFinal callback routine that implements the aggregate
5950** function.
5952** This routine must be called from the same thread in which
5953** the aggregate SQL function is running.
5955SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
5958** CAPI3REF: User Data For Functions
5959** METHOD: sqlite3_context
5961** ^The sqlite3_user_data() interface returns a copy of
5962** the pointer that was the pUserData parameter (the 5th parameter)
5963** of the [sqlite3_create_function()]
5964** and [sqlite3_create_function16()] routines that originally
5965** registered the application defined function.
5967** This routine must be called from the same thread in which
5968** the application-defined function is running.
5970SQLITE_API void *sqlite3_user_data(sqlite3_context*);
5973** CAPI3REF: Database Connection For Functions
5974** METHOD: sqlite3_context
5976** ^The sqlite3_context_db_handle() interface returns a copy of
5977** the pointer to the [database connection] (the 1st parameter)
5978** of the [sqlite3_create_function()]
5979** and [sqlite3_create_function16()] routines that originally
5980** registered the application defined function.
5982SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
5985** CAPI3REF: Function Auxiliary Data
5986** METHOD: sqlite3_context
5988** These functions may be used by (non-aggregate) SQL functions to
5989** associate metadata with argument values. If the same value is passed to
5990** multiple invocations of the same SQL function during query execution, under
5991** some circumstances the associated metadata may be preserved. An example
5992** of where this might be useful is in a regular-expression matching
5993** function. The compiled version of the regular expression can be stored as
5994** metadata associated with the pattern string.
5995** Then as long as the pattern string remains the same,
5996** the compiled regular expression can be reused on multiple
5997** invocations of the same function.
5999** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata
6000** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
6001** value to the application-defined function. ^N is zero for the left-most
6002** function argument. ^If there is no metadata
6003** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
6004** returns a NULL pointer.
6006** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
6007** argument of the application-defined function. ^Subsequent
6008** calls to sqlite3_get_auxdata(C,N) return P from the most recent
6009** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
6010** NULL if the metadata has been discarded.
6011** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
6012** SQLite will invoke the destructor function X with parameter P exactly
6013** once, when the metadata is discarded.
6014** SQLite is free to discard the metadata at any time, including: <ul>
6015** <li> ^(when the corresponding function parameter changes)^, or
6016** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
6017** SQL statement)^, or
6018** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
6019** parameter)^, or
6020** <li> ^(during the original sqlite3_set_auxdata() call when a memory
6021** allocation error occurs.)^ </ul>
6023** Note the last bullet in particular. The destructor X in
6024** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
6025** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata()
6026** should be called near the end of the function implementation and the
6027** function implementation should not make any use of P after
6028** sqlite3_set_auxdata() has been called.
6030** ^(In practice, metadata is preserved between function calls for
6031** function parameters that are compile-time constants, including literal
6032** values and [parameters] and expressions composed from the same.)^
6034** The value of the N parameter to these interfaces should be non-negative.
6035** Future enhancements may make use of negative N values to define new
6036** kinds of function caching behavior.
6038** These routines must be called from the same thread in which
6039** the SQL function is running.
6041SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
6042SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
6046** CAPI3REF: Constants Defining Special Destructor Behavior
6048** These are special values for the destructor that is passed in as the
6049** final argument to routines like [sqlite3_result_blob()]. ^If the destructor
6050** argument is SQLITE_STATIC, it means that the content pointer is constant
6051** and will never change. It does not need to be destroyed. ^The
6052** SQLITE_TRANSIENT value means that the content will likely change in
6053** the near future and that SQLite should make its own private copy of
6054** the content before returning.
6056** The typedef is necessary to work around problems in certain
6057** C++ compilers.
6059typedef void (*sqlite3_destructor_type)(void*);
6060#define SQLITE_STATIC ((sqlite3_destructor_type)0)
6061#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
6064** CAPI3REF: Setting The Result Of An SQL Function
6065** METHOD: sqlite3_context
6067** These routines are used by the xFunc or xFinal callbacks that
6068** implement SQL functions and aggregates. See
6069** [sqlite3_create_function()] and [sqlite3_create_function16()]
6070** for additional information.
6072** These functions work very much like the [parameter binding] family of
6073** functions used to bind values to host parameters in prepared statements.
6074** Refer to the [SQL parameter] documentation for additional information.
6076** ^The sqlite3_result_blob() interface sets the result from
6077** an application-defined function to be the BLOB whose content is pointed
6078** to by the second parameter and which is N bytes long where N is the
6079** third parameter.
6081** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
6082** interfaces set the result of the application-defined function to be
6083** a BLOB containing all zero bytes and N bytes in size.
6085** ^The sqlite3_result_double() interface sets the result from
6086** an application-defined function to be a floating point value specified
6087** by its 2nd argument.
6089** ^The sqlite3_result_error() and sqlite3_result_error16() functions
6090** cause the implemented SQL function to throw an exception.
6091** ^SQLite uses the string pointed to by the
6092** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
6093** as the text of an error message. ^SQLite interprets the error
6094** message string from sqlite3_result_error() as UTF-8. ^SQLite
6095** interprets the string from sqlite3_result_error16() as UTF-16 using
6096** the same [byte-order determination rules] as [sqlite3_bind_text16()].
6097** ^If the third parameter to sqlite3_result_error()
6098** or sqlite3_result_error16() is negative then SQLite takes as the error
6099** message all text up through the first zero character.
6100** ^If the third parameter to sqlite3_result_error() or
6101** sqlite3_result_error16() is non-negative then SQLite takes that many
6102** bytes (not characters) from the 2nd parameter as the error message.
6103** ^The sqlite3_result_error() and sqlite3_result_error16()
6104** routines make a private copy of the error message text before
6105** they return. Hence, the calling function can deallocate or
6106** modify the text after they return without harm.
6107** ^The sqlite3_result_error_code() function changes the error code
6108** returned by SQLite as a result of an error in a function. ^By default,
6109** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error()
6110** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
6112** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
6113** error indicating that a string or BLOB is too long to represent.
6115** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
6116** error indicating that a memory allocation failed.
6118** ^The sqlite3_result_int() interface sets the return value
6119** of the application-defined function to be the 32-bit signed integer
6120** value given in the 2nd argument.
6121** ^The sqlite3_result_int64() interface sets the return value
6122** of the application-defined function to be the 64-bit signed integer
6123** value given in the 2nd argument.
6125** ^The sqlite3_result_null() interface sets the return value
6126** of the application-defined function to be NULL.
6128** ^The sqlite3_result_text(), sqlite3_result_text16(),
6129** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
6130** set the return value of the application-defined function to be
6131** a text string which is represented as UTF-8, UTF-16 native byte order,
6132** UTF-16 little endian, or UTF-16 big endian, respectively.
6133** ^The sqlite3_result_text64() interface sets the return value of an
6134** application-defined function to be a text string in an encoding
6135** specified by the fifth (and last) parameter, which must be one
6137** ^SQLite takes the text result from the application from
6138** the 2nd parameter of the sqlite3_result_text* interfaces.
6139** ^If the 3rd parameter to the sqlite3_result_text* interfaces
6140** is negative, then SQLite takes result text from the 2nd parameter
6141** through the first zero character.
6142** ^If the 3rd parameter to the sqlite3_result_text* interfaces
6143** is non-negative, then as many bytes (not characters) of the text
6144** pointed to by the 2nd parameter are taken as the application-defined
6145** function result. If the 3rd parameter is non-negative, then it
6146** must be the byte offset into the string where the NUL terminator would
6147** appear if the string where NUL terminated. If any NUL characters occur
6148** in the string at a byte offset that is less than the value of the 3rd
6149** parameter, then the resulting string will contain embedded NULs and the
6150** result of expressions operating on strings with embedded NULs is undefined.
6151** ^If the 4th parameter to the sqlite3_result_text* interfaces
6152** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
6153** function as the destructor on the text or BLOB result when it has
6154** finished using that result.
6155** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
6156** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
6157** assumes that the text or BLOB result is in constant space and does not
6158** copy the content of the parameter nor call a destructor on the content
6159** when it has finished using that result.
6160** ^If the 4th parameter to the sqlite3_result_text* interfaces
6161** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
6162** then SQLite makes a copy of the result into space obtained
6163** from [sqlite3_malloc()] before it returns.
6165** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and
6166** sqlite3_result_text16be() routines, and for sqlite3_result_text64()
6167** when the encoding is not UTF8, if the input UTF16 begins with a
6168** byte-order mark (BOM, U+FEFF) then the BOM is removed from the
6169** string and the rest of the string is interpreted according to the
6170** byte-order specified by the BOM. ^The byte-order specified by
6171** the BOM at the beginning of the text overrides the byte-order
6172** specified by the interface procedure. ^So, for example, if
6173** sqlite3_result_text16le() is invoked with text that begins
6174** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the
6175** first two bytes of input are skipped and the remaining input
6176** is interpreted as UTF16BE text.
6178** ^For UTF16 input text to the sqlite3_result_text16(),
6179** sqlite3_result_text16be(), sqlite3_result_text16le(), and
6180** sqlite3_result_text64() routines, if the text contains invalid
6181** UTF16 characters, the invalid characters might be converted
6182** into the unicode replacement character, U+FFFD.
6184** ^The sqlite3_result_value() interface sets the result of
6185** the application-defined function to be a copy of the
6186** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The
6187** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
6188** so that the [sqlite3_value] specified in the parameter may change or
6189** be deallocated after sqlite3_result_value() returns without harm.
6190** ^A [protected sqlite3_value] object may always be used where an
6191** [unprotected sqlite3_value] object is required, so either
6192** kind of [sqlite3_value] object can be used with this interface.
6194** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
6195** SQL NULL value, just like [sqlite3_result_null(C)], except that it
6196** also associates the host-language pointer P or type T with that
6197** NULL value such that the pointer can be retrieved within an
6198** [application-defined SQL function] using [sqlite3_value_pointer()].
6199** ^If the D parameter is not NULL, then it is a pointer to a destructor
6200** for the P parameter. ^SQLite invokes D with P as its only argument
6201** when SQLite is finished with P. The T parameter should be a static
6202** string and preferably a string literal. The sqlite3_result_pointer()
6203** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
6205** If these routines are called from within the different thread
6206** than the one containing the application-defined function that received
6207** the [sqlite3_context] pointer, the results are undefined.
6209SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
6210SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
6211 sqlite3_uint64,void(*)(void*));
6212SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
6213SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
6214SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
6215SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
6216SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
6217SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
6218SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
6219SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
6220SQLITE_API void sqlite3_result_null(sqlite3_context*);
6221SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
6222SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
6223 void(*)(void*), unsigned char encoding);
6224SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
6225SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
6226SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
6227SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
6228SQLITE_API void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
6229SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
6230SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
6234** CAPI3REF: Setting The Subtype Of An SQL Function
6235** METHOD: sqlite3_context
6237** The sqlite3_result_subtype(C,T) function causes the subtype of
6238** the result from the [application-defined SQL function] with
6239** [sqlite3_context] C to be the value T. Only the lower 8 bits
6240** of the subtype T are preserved in current versions of SQLite;
6241** higher order bits are discarded.
6242** The number of subtype bytes preserved by SQLite might increase
6243** in future releases of SQLite.
6245SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int);
6248** CAPI3REF: Define New Collating Sequences
6249** METHOD: sqlite3
6251** ^These functions add, remove, or modify a [collation] associated
6252** with the [database connection] specified as the first argument.
6254** ^The name of the collation is a UTF-8 string
6255** for sqlite3_create_collation() and sqlite3_create_collation_v2()
6256** and a UTF-16 string in native byte order for sqlite3_create_collation16().
6257** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
6258** considered to be the same name.
6260** ^(The third argument (eTextRep) must be one of the constants:
6261** <ul>
6262** <li> [SQLITE_UTF8],
6263** <li> [SQLITE_UTF16LE],
6264** <li> [SQLITE_UTF16BE],
6265** <li> [SQLITE_UTF16], or
6266** <li> [SQLITE_UTF16_ALIGNED].
6267** </ul>)^
6268** ^The eTextRep argument determines the encoding of strings passed
6269** to the collating function callback, xCompare.
6270** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
6271** force strings to be UTF16 with native byte order.
6272** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
6273** on an even byte address.
6275** ^The fourth argument, pArg, is an application data pointer that is passed
6276** through as the first argument to the collating function callback.
6278** ^The fifth argument, xCompare, is a pointer to the collating function.
6279** ^Multiple collating functions can be registered using the same name but
6280** with different eTextRep parameters and SQLite will use whichever
6281** function requires the least amount of data transformation.
6282** ^If the xCompare argument is NULL then the collating function is
6283** deleted. ^When all collating functions having the same name are deleted,
6284** that collation is no longer usable.
6286** ^The collating function callback is invoked with a copy of the pArg
6287** application data pointer and with two strings in the encoding specified
6288** by the eTextRep argument. The two integer parameters to the collating
6289** function callback are the length of the two strings, in bytes. The collating
6290** function must return an integer that is negative, zero, or positive
6291** if the first string is less than, equal to, or greater than the second,
6292** respectively. A collating function must always return the same answer
6293** given the same inputs. If two or more collating functions are registered
6294** to the same collation name (using different eTextRep values) then all
6295** must give an equivalent answer when invoked with equivalent strings.
6296** The collating function must obey the following properties for all
6297** strings A, B, and C:
6299** <ol>
6300** <li> If A==B then B==A.
6301** <li> If A==B and B==C then A==C.
6302** <li> If A&lt;B THEN B&gt;A.
6303** <li> If A&lt;B and B&lt;C then A&lt;C.
6304** </ol>
6306** If a collating function fails any of the above constraints and that
6307** collating function is registered and used, then the behavior of SQLite
6308** is undefined.
6310** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
6311** with the addition that the xDestroy callback is invoked on pArg when
6312** the collating function is deleted.
6313** ^Collating functions are deleted when they are overridden by later
6314** calls to the collation creation functions or when the
6315** [database connection] is closed using [sqlite3_close()].
6317** ^The xDestroy callback is <u>not</u> called if the
6318** sqlite3_create_collation_v2() function fails. Applications that invoke
6319** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
6320** check the return code and dispose of the application data pointer
6321** themselves rather than expecting SQLite to deal with it for them.
6322** This is different from every other SQLite interface. The inconsistency
6323** is unfortunate but cannot be changed without breaking backwards
6324** compatibility.
6326** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
6328SQLITE_API int sqlite3_create_collation(
6329 sqlite3*,
6330 const char *zName,
6331 int eTextRep,
6332 void *pArg,
6333 int(*xCompare)(void*,int,const void*,int,const void*)
6335SQLITE_API int sqlite3_create_collation_v2(
6336 sqlite3*,
6337 const char *zName,
6338 int eTextRep,
6339 void *pArg,
6340 int(*xCompare)(void*,int,const void*,int,const void*),
6341 void(*xDestroy)(void*)
6343SQLITE_API int sqlite3_create_collation16(
6344 sqlite3*,
6345 const void *zName,
6346 int eTextRep,
6347 void *pArg,
6348 int(*xCompare)(void*,int,const void*,int,const void*)
6352** CAPI3REF: Collation Needed Callbacks
6353** METHOD: sqlite3
6355** ^To avoid having to register all collation sequences before a database
6356** can be used, a single callback function may be registered with the
6357** [database connection] to be invoked whenever an undefined collation
6358** sequence is required.
6360** ^If the function is registered using the sqlite3_collation_needed() API,
6361** then it is passed the names of undefined collation sequences as strings
6362** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
6363** the names are passed as UTF-16 in machine native byte order.
6364** ^A call to either function replaces the existing collation-needed callback.
6366** ^(When the callback is invoked, the first argument passed is a copy
6367** of the second argument to sqlite3_collation_needed() or
6368** sqlite3_collation_needed16(). The second argument is the database
6369** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
6370** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
6371** sequence function required. The fourth parameter is the name of the
6372** required collation sequence.)^
6374** The callback function should register the desired collation using
6375** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
6376** [sqlite3_create_collation_v2()].
6378SQLITE_API int sqlite3_collation_needed(
6379 sqlite3*,
6380 void*,
6381 void(*)(void*,sqlite3*,int eTextRep,const char*)
6383SQLITE_API int sqlite3_collation_needed16(
6384 sqlite3*,
6385 void*,
6386 void(*)(void*,sqlite3*,int eTextRep,const void*)
6391** Specify the activation key for a CEROD database. Unless
6392** activated, none of the CEROD routines will work.
6394SQLITE_API void sqlite3_activate_cerod(
6395 const char *zPassPhrase /* Activation phrase */
6400** CAPI3REF: Suspend Execution For A Short Time
6402** The sqlite3_sleep() function causes the current thread to suspend execution
6403** for at least a number of milliseconds specified in its parameter.
6405** If the operating system does not support sleep requests with
6406** millisecond time resolution, then the time will be rounded up to
6407** the nearest second. The number of milliseconds of sleep actually
6408** requested from the operating system is returned.
6410** ^SQLite implements this interface by calling the xSleep()
6411** method of the default [sqlite3_vfs] object. If the xSleep() method
6412** of the default VFS is not implemented correctly, or not implemented at
6413** all, then the behavior of sqlite3_sleep() may deviate from the description
6414** in the previous paragraphs.
6416SQLITE_API int sqlite3_sleep(int);
6419** CAPI3REF: Name Of The Folder Holding Temporary Files
6421** ^(If this global variable is made to point to a string which is
6422** the name of a folder (a.k.a. directory), then all temporary files
6423** created by SQLite when using a built-in [sqlite3_vfs | VFS]
6424** will be placed in that directory.)^ ^If this variable
6425** is a NULL pointer, then SQLite performs a search for an appropriate
6426** temporary file directory.
6428** Applications are strongly discouraged from using this global variable.
6429** It is required to set a temporary folder on Windows Runtime (WinRT).
6430** But for all other platforms, it is highly recommended that applications
6431** neither read nor write this variable. This global variable is a relic
6432** that exists for backwards compatibility of legacy applications and should
6433** be avoided in new projects.
6435** It is not safe to read or modify this variable in more than one
6436** thread at a time. It is not safe to read or modify this variable
6437** if a [database connection] is being used at the same time in a separate
6438** thread.
6439** It is intended that this variable be set once
6440** as part of process initialization and before any SQLite interface
6441** routines have been called and that this variable remain unchanged
6442** thereafter.
6444** ^The [temp_store_directory pragma] may modify this variable and cause
6445** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
6446** the [temp_store_directory pragma] always assumes that any string
6447** that this variable points to is held in memory obtained from
6448** [sqlite3_malloc] and the pragma may attempt to free that memory
6449** using [sqlite3_free].
6450** Hence, if this variable is modified directly, either it should be
6451** made NULL or made to point to memory obtained from [sqlite3_malloc]
6452** or else the use of the [temp_store_directory pragma] should be avoided.
6453** Except when requested by the [temp_store_directory pragma], SQLite
6454** does not free the memory that sqlite3_temp_directory points to. If
6455** the application wants that memory to be freed, it must do
6456** so itself, taking care to only do so after all [database connection]
6457** objects have been destroyed.
6459** <b>Note to Windows Runtime users:</b> The temporary directory must be set
6460** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various
6461** features that require the use of temporary files may fail. Here is an
6462** example of how to do this using C++ with the Windows Runtime:
6464** <blockquote><pre>
6465** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
6466** &nbsp; TemporaryFolder->Path->Data();
6467** char zPathBuf&#91;MAX_PATH + 1&#93;;
6468** memset(zPathBuf, 0, sizeof(zPathBuf));
6469** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
6470** &nbsp; NULL, NULL);
6471** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
6472** </pre></blockquote>
6474SQLITE_API char *sqlite3_temp_directory;
6477** CAPI3REF: Name Of The Folder Holding Database Files
6479** ^(If this global variable is made to point to a string which is
6480** the name of a folder (a.k.a. directory), then all database files
6481** specified with a relative pathname and created or accessed by
6482** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
6483** to be relative to that directory.)^ ^If this variable is a NULL
6484** pointer, then SQLite assumes that all database files specified
6485** with a relative pathname are relative to the current directory
6486** for the process. Only the windows VFS makes use of this global
6487** variable; it is ignored by the unix VFS.
6489** Changing the value of this variable while a database connection is
6490** open can result in a corrupt database.
6492** It is not safe to read or modify this variable in more than one
6493** thread at a time. It is not safe to read or modify this variable
6494** if a [database connection] is being used at the same time in a separate
6495** thread.
6496** It is intended that this variable be set once
6497** as part of process initialization and before any SQLite interface
6498** routines have been called and that this variable remain unchanged
6499** thereafter.
6501** ^The [data_store_directory pragma] may modify this variable and cause
6502** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore,
6503** the [data_store_directory pragma] always assumes that any string
6504** that this variable points to is held in memory obtained from
6505** [sqlite3_malloc] and the pragma may attempt to free that memory
6506** using [sqlite3_free].
6507** Hence, if this variable is modified directly, either it should be
6508** made NULL or made to point to memory obtained from [sqlite3_malloc]
6509** or else the use of the [data_store_directory pragma] should be avoided.
6511SQLITE_API char *sqlite3_data_directory;
6514** CAPI3REF: Win32 Specific Interface
6516** These interfaces are available only on Windows. The
6517** [sqlite3_win32_set_directory] interface is used to set the value associated
6518** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to
6519** zValue, depending on the value of the type parameter. The zValue parameter
6520** should be NULL to cause the previous value to be freed via [sqlite3_free];
6521** a non-NULL value will be copied into memory obtained from [sqlite3_malloc]
6522** prior to being used. The [sqlite3_win32_set_directory] interface returns
6523** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported,
6524** or [SQLITE_NOMEM] if memory could not be allocated. The value of the
6525** [sqlite3_data_directory] variable is intended to act as a replacement for
6526** the current directory on the sub-platforms of Win32 where that concept is
6527** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and
6528** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the
6529** sqlite3_win32_set_directory interface except the string parameter must be
6530** UTF-8 or UTF-16, respectively.
6532SQLITE_API int sqlite3_win32_set_directory(
6533 unsigned long type, /* Identifier for directory being set or reset */
6534 void *zValue /* New value for directory being set or reset */
6536SQLITE_API int sqlite3_win32_set_directory8(unsigned long type, const char *zValue);
6537SQLITE_API int sqlite3_win32_set_directory16(unsigned long type, const void *zValue);
6540** CAPI3REF: Win32 Directory Types
6542** These macros are only available on Windows. They define the allowed values
6543** for the type argument to the [sqlite3_win32_set_directory] interface.
6549** CAPI3REF: Test For Auto-Commit Mode
6550** KEYWORDS: {autocommit mode}
6551** METHOD: sqlite3
6553** ^The sqlite3_get_autocommit() interface returns non-zero or
6554** zero if the given database connection is or is not in autocommit mode,
6555** respectively. ^Autocommit mode is on by default.
6556** ^Autocommit mode is disabled by a [BEGIN] statement.
6557** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
6559** If certain kinds of errors occur on a statement within a multi-statement
6560** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
6562** transaction might be rolled back automatically. The only way to
6563** find out whether SQLite automatically rolled back the transaction after
6564** an error is to use this function.
6566** If another thread changes the autocommit status of the database
6567** connection while this routine is running, then the return value
6568** is undefined.
6570SQLITE_API int sqlite3_get_autocommit(sqlite3*);
6573** CAPI3REF: Find The Database Handle Of A Prepared Statement
6574** METHOD: sqlite3_stmt
6576** ^The sqlite3_db_handle interface returns the [database connection] handle
6577** to which a [prepared statement] belongs. ^The [database connection]
6578** returned by sqlite3_db_handle is the same [database connection]
6579** that was the first argument
6580** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
6581** create the statement in the first place.
6583SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
6586** CAPI3REF: Return The Schema Name For A Database Connection
6587** METHOD: sqlite3
6589** ^The sqlite3_db_name(D,N) interface returns a pointer to the schema name
6590** for the N-th database on database connection D, or a NULL pointer of N is
6591** out of range. An N value of 0 means the main database file. An N of 1 is
6592** the "temp" schema. Larger values of N correspond to various ATTACH-ed
6593** databases.
6595** Space to hold the string that is returned by sqlite3_db_name() is managed
6596** by SQLite itself. The string might be deallocated by any operation that
6597** changes the schema, including [ATTACH] or [DETACH] or calls to
6598** [sqlite3_serialize()] or [sqlite3_deserialize()], even operations that
6599** occur on a different thread. Applications that need to
6600** remember the string long-term should make their own copy. Applications that
6601** are accessing the same database connection simultaneously on multiple
6602** threads should mutex-protect calls to this API and should make their own
6603** private copy of the result prior to releasing the mutex.
6605SQLITE_API const char *sqlite3_db_name(sqlite3 *db, int N);
6608** CAPI3REF: Return The Filename For A Database Connection
6609** METHOD: sqlite3
6611** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename
6612** associated with database N of connection D.
6613** ^If there is no attached database N on the database
6614** connection D, or if database N is a temporary or in-memory database, then
6615** this function will return either a NULL pointer or an empty string.
6617** ^The string value returned by this routine is owned and managed by
6618** the database connection. ^The value will be valid until the database N
6619** is [DETACH]-ed or until the database connection closes.
6621** ^The filename returned by this function is the output of the
6622** xFullPathname method of the [VFS]. ^In other words, the filename
6623** will be an absolute pathname, even if the filename used
6624** to open the database originally was a URI or relative pathname.
6626** If the filename pointer returned by this routine is not NULL, then it
6627** can be used as the filename input parameter to these routines:
6628** <ul>
6629** <li> [sqlite3_uri_parameter()]
6630** <li> [sqlite3_uri_boolean()]
6631** <li> [sqlite3_uri_int64()]
6632** <li> [sqlite3_filename_database()]
6633** <li> [sqlite3_filename_journal()]
6634** <li> [sqlite3_filename_wal()]
6635** </ul>
6637SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
6640** CAPI3REF: Determine if a database is read-only
6641** METHOD: sqlite3
6643** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
6644** of connection D is read-only, 0 if it is read/write, or -1 if N is not
6645** the name of a database on connection D.
6647SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
6650** CAPI3REF: Determine the transaction state of a database
6651** METHOD: sqlite3
6653** ^The sqlite3_txn_state(D,S) interface returns the current
6654** [transaction state] of schema S in database connection D. ^If S is NULL,
6655** then the highest transaction state of any schema on database connection D
6656** is returned. Transaction states are (in order of lowest to highest):
6657** <ol>
6658** <li value="0"> SQLITE_TXN_NONE
6659** <li value="1"> SQLITE_TXN_READ
6660** <li value="2"> SQLITE_TXN_WRITE
6661** </ol>
6662** ^If the S argument to sqlite3_txn_state(D,S) is not the name of
6663** a valid schema, then -1 is returned.
6665SQLITE_API int sqlite3_txn_state(sqlite3*,const char *zSchema);
6668** CAPI3REF: Allowed return values from [sqlite3_txn_state()]
6669** KEYWORDS: {transaction state}
6671** These constants define the current transaction state of a database file.
6672** ^The [sqlite3_txn_state(D,S)] interface returns one of these
6673** constants in order to describe the transaction state of schema S
6674** in [database connection] D.
6676** <dl>
6678** <dd>The SQLITE_TXN_NONE state means that no transaction is currently
6679** pending.</dd>
6682** <dd>The SQLITE_TXN_READ state means that the database is currently
6683** in a read transaction. Content has been read from the database file
6684** but nothing in the database file has changed. The transaction state
6685** will advanced to SQLITE_TXN_WRITE if any changes occur and there are
6686** no other conflicting concurrent write transactions. The transaction
6687** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or
6688** [COMMIT].</dd>
6691** <dd>The SQLITE_TXN_WRITE state means that the database is currently
6692** in a write transaction. Content has been written to the database file
6693** but has not yet committed. The transaction state will change to
6694** to SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd>
6696#define SQLITE_TXN_NONE 0
6697#define SQLITE_TXN_READ 1
6698#define SQLITE_TXN_WRITE 2
6701** CAPI3REF: Find the next prepared statement
6702** METHOD: sqlite3
6704** ^This interface returns a pointer to the next [prepared statement] after
6705** pStmt associated with the [database connection] pDb. ^If pStmt is NULL
6706** then this interface returns a pointer to the first prepared statement
6707** associated with the database connection pDb. ^If no prepared statement
6708** satisfies the conditions of this routine, it returns NULL.
6710** The [database connection] pointer D in a call to
6711** [sqlite3_next_stmt(D,S)] must refer to an open database
6712** connection and in particular must not be a NULL pointer.
6714SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
6717** CAPI3REF: Commit And Rollback Notification Callbacks
6718** METHOD: sqlite3
6720** ^The sqlite3_commit_hook() interface registers a callback
6721** function to be invoked whenever a transaction is [COMMIT | committed].
6722** ^Any callback set by a previous call to sqlite3_commit_hook()
6723** for the same database connection is overridden.
6724** ^The sqlite3_rollback_hook() interface registers a callback
6725** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
6726** ^Any callback set by a previous call to sqlite3_rollback_hook()
6727** for the same database connection is overridden.
6728** ^The pArg argument is passed through to the callback.
6729** ^If the callback on a commit hook function returns non-zero,
6730** then the commit is converted into a rollback.
6732** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
6733** return the P argument from the previous call of the same function
6734** on the same [database connection] D, or NULL for
6735** the first call for each function on D.
6737** The commit and rollback hook callbacks are not reentrant.
6738** The callback implementation must not do anything that will modify
6739** the database connection that invoked the callback. Any actions
6740** to modify the database connection must be deferred until after the
6741** completion of the [sqlite3_step()] call that triggered the commit
6742** or rollback hook in the first place.
6743** Note that running any other SQL statements, including SELECT statements,
6744** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
6745** the database connections for the meaning of "modify" in this paragraph.
6747** ^Registering a NULL function disables the callback.
6749** ^When the commit hook callback routine returns zero, the [COMMIT]
6750** operation is allowed to continue normally. ^If the commit hook
6751** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
6752** ^The rollback hook is invoked on a rollback that results from a commit
6753** hook returning non-zero, just as it would be with any other rollback.
6755** ^For the purposes of this API, a transaction is said to have been
6756** rolled back if an explicit "ROLLBACK" statement is executed, or
6757** an error or constraint causes an implicit rollback to occur.
6758** ^The rollback callback is not invoked if a transaction is
6759** automatically rolled back because the database connection is closed.
6761** See also the [sqlite3_update_hook()] interface.
6763SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
6764SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
6767** CAPI3REF: Autovacuum Compaction Amount Callback
6768** METHOD: sqlite3
6770** ^The sqlite3_autovacuum_pages(D,C,P,X) interface registers a callback
6771** function C that is invoked prior to each autovacuum of the database
6772** file. ^The callback is passed a copy of the generic data pointer (P),
6773** the schema-name of the attached database that is being autovacuumed,
6774** the the size of the database file in pages, the number of free pages,
6775** and the number of bytes per page, respectively. The callback should
6776** return the number of free pages that should be removed by the
6777** autovacuum. ^If the callback returns zero, then no autovacuum happens.
6778** ^If the value returned is greater than or equal to the number of
6779** free pages, then a complete autovacuum happens.
6781** <p>^If there are multiple ATTACH-ed database files that are being
6782** modified as part of a transaction commit, then the autovacuum pages
6783** callback is invoked separately for each file.
6785** <p><b>The callback is not reentrant.</b> The callback function should
6786** not attempt to invoke any other SQLite interface. If it does, bad
6787** things may happen, including segmentation faults and corrupt database
6788** files. The callback function should be a simple function that
6789** does some arithmetic on its input parameters and returns a result.
6791** ^The X parameter to sqlite3_autovacuum_pages(D,C,P,X) is an optional
6792** destructor for the P parameter. ^If X is not NULL, then X(P) is
6793** invoked whenever the database connection closes or when the callback
6794** is overwritten by another invocation of sqlite3_autovacuum_pages().
6796** <p>^There is only one autovacuum pages callback per database connection.
6797** ^Each call to the sqlite3_autovacuum_pages() interface overrides all
6798** previous invocations for that database connection. ^If the callback
6799** argument (C) to sqlite3_autovacuum_pages(D,C,P,X) is a NULL pointer,
6800** then the autovacuum steps callback is cancelled. The return value
6801** from sqlite3_autovacuum_pages() is normally SQLITE_OK, but might
6802** be some other error code if something goes wrong. The current
6803** implementation will only return SQLITE_OK or SQLITE_MISUSE, but other
6804** return codes might be added in future releases.
6806** <p>If no autovacuum pages callback is specified (the usual case) or
6807** a NULL pointer is provided for the callback,
6808** then the default behavior is to vacuum all free pages. So, in other
6809** words, the default behavior is the same as if the callback function
6810** were something like this:
6812** <blockquote><pre>
6813** &nbsp; unsigned int demonstration_autovac_pages_callback(
6814** &nbsp; void *pClientData,
6815** &nbsp; const char *zSchema,
6816** &nbsp; unsigned int nDbPage,
6817** &nbsp; unsigned int nFreePage,
6818** &nbsp; unsigned int nBytePerPage
6819** &nbsp; ){
6820** &nbsp; return nFreePage;
6821** &nbsp; }
6822** </pre></blockquote>
6824SQLITE_API int sqlite3_autovacuum_pages(
6825 sqlite3 *db,
6826 unsigned int(*)(void*,const char*,unsigned int,unsigned int,unsigned int),
6827 void*,
6828 void(*)(void*)
6833** CAPI3REF: Data Change Notification Callbacks
6834** METHOD: sqlite3
6836** ^The sqlite3_update_hook() interface registers a callback function
6837** with the [database connection] identified by the first argument
6838** to be invoked whenever a row is updated, inserted or deleted in
6839** a [rowid table].
6840** ^Any callback set by a previous call to this function
6841** for the same database connection is overridden.
6843** ^The second argument is a pointer to the function to invoke when a
6844** row is updated, inserted or deleted in a rowid table.
6845** ^The first argument to the callback is a copy of the third argument
6846** to sqlite3_update_hook().
6847** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
6848** or [SQLITE_UPDATE], depending on the operation that caused the callback
6849** to be invoked.
6850** ^The third and fourth arguments to the callback contain pointers to the
6851** database and table name containing the affected row.
6852** ^The final callback parameter is the [rowid] of the row.
6853** ^In the case of an update, this is the [rowid] after the update takes place.
6855** ^(The update hook is not invoked when internal system tables are
6856** modified (i.e. sqlite_sequence).)^
6857** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
6859** ^In the current implementation, the update hook
6860** is not invoked when conflicting rows are deleted because of an
6861** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook
6862** invoked when rows are deleted using the [truncate optimization].
6863** The exceptions defined in this paragraph might change in a future
6864** release of SQLite.
6866** The update hook implementation must not do anything that will modify
6867** the database connection that invoked the update hook. Any actions
6868** to modify the database connection must be deferred until after the
6869** completion of the [sqlite3_step()] call that triggered the update hook.
6870** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
6871** database connections for the meaning of "modify" in this paragraph.
6873** ^The sqlite3_update_hook(D,C,P) function
6874** returns the P argument from the previous call
6875** on the same [database connection] D, or NULL for
6876** the first call on D.
6878** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
6879** and [sqlite3_preupdate_hook()] interfaces.
6881SQLITE_API void *sqlite3_update_hook(
6882 sqlite3*,
6883 void(*)(void *,int ,char const *,char const *,sqlite3_int64),
6884 void*
6888** CAPI3REF: Enable Or Disable Shared Pager Cache
6890** ^(This routine enables or disables the sharing of the database cache
6891** and schema data structures between [database connection | connections]
6892** to the same database. Sharing is enabled if the argument is true
6893** and disabled if the argument is false.)^
6895** ^Cache sharing is enabled and disabled for an entire process.
6896** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
6897** In prior versions of SQLite,
6898** sharing was enabled or disabled for each thread separately.
6900** ^(The cache sharing mode set by this interface effects all subsequent
6901** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
6902** Existing database connections continue to use the sharing mode
6903** that was in effect at the time they were opened.)^
6905** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
6906** successfully. An [error code] is returned otherwise.)^
6908** ^Shared cache is disabled by default. It is recommended that it stay
6909** that way. In other words, do not use this routine. This interface
6910** continues to be provided for historical compatibility, but its use is
6911** discouraged. Any use of shared cache is discouraged. If shared cache
6912** must be used, it is recommended that shared cache only be enabled for
6913** individual database connections using the [sqlite3_open_v2()] interface
6914** with the [SQLITE_OPEN_SHAREDCACHE] flag.
6916** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
6917** and will always return SQLITE_MISUSE. On those systems,
6918** shared cache mode should be enabled per-database connection via
6919** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
6921** This interface is threadsafe on processors where writing a
6922** 32-bit integer is atomic.
6924** See Also: [SQLite Shared-Cache Mode]
6926SQLITE_API int sqlite3_enable_shared_cache(int);
6929** CAPI3REF: Attempt To Free Heap Memory
6931** ^The sqlite3_release_memory() interface attempts to free N bytes
6932** of heap memory by deallocating non-essential memory allocations
6933** held by the database library. Memory used to cache database
6934** pages to improve performance is an example of non-essential memory.
6935** ^sqlite3_release_memory() returns the number of bytes actually freed,
6936** which might be more or less than the amount requested.
6937** ^The sqlite3_release_memory() routine is a no-op returning zero
6938** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
6940** See also: [sqlite3_db_release_memory()]
6942SQLITE_API int sqlite3_release_memory(int);
6945** CAPI3REF: Free Memory Used By A Database Connection
6946** METHOD: sqlite3
6948** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
6949** memory as possible from database connection D. Unlike the
6950** [sqlite3_release_memory()] interface, this interface is in effect even
6951** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
6952** omitted.
6954** See also: [sqlite3_release_memory()]
6956SQLITE_API int sqlite3_db_release_memory(sqlite3*);
6959** CAPI3REF: Impose A Limit On Heap Size
6961** These interfaces impose limits on the amount of heap memory that will be
6962** by all database connections within a single process.
6964** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
6965** soft limit on the amount of heap memory that may be allocated by SQLite.
6966** ^SQLite strives to keep heap memory utilization below the soft heap
6967** limit by reducing the number of pages held in the page cache
6968** as heap memory usages approaches the limit.
6969** ^The soft heap limit is "soft" because even though SQLite strives to stay
6970** below the limit, it will exceed the limit rather than generate
6971** an [SQLITE_NOMEM] error. In other words, the soft heap limit
6972** is advisory only.
6974** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of
6975** N bytes on the amount of memory that will be allocated. ^The
6976** sqlite3_hard_heap_limit64(N) interface is similar to
6977** sqlite3_soft_heap_limit64(N) except that memory allocations will fail
6978** when the hard heap limit is reached.
6980** ^The return value from both sqlite3_soft_heap_limit64() and
6981** sqlite3_hard_heap_limit64() is the size of
6982** the heap limit prior to the call, or negative in the case of an
6983** error. ^If the argument N is negative
6984** then no change is made to the heap limit. Hence, the current
6985** size of heap limits can be determined by invoking
6986** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1).
6988** ^Setting the heap limits to zero disables the heap limiter mechanism.
6990** ^The soft heap limit may not be greater than the hard heap limit.
6991** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N)
6992** is invoked with a value of N that is greater than the hard heap limit,
6993** the the soft heap limit is set to the value of the hard heap limit.
6994** ^The soft heap limit is automatically enabled whenever the hard heap
6995** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and
6996** the soft heap limit is outside the range of 1..N, then the soft heap
6997** limit is set to N. ^Invoking sqlite3_soft_heap_limit64(0) when the
6998** hard heap limit is enabled makes the soft heap limit equal to the
6999** hard heap limit.
7001** The memory allocation limits can also be adjusted using
7002** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit].
7004** ^(The heap limits are not enforced in the current implementation
7005** if one or more of following conditions are true:
7007** <ul>
7008** <li> The limit value is set to zero.
7009** <li> Memory accounting is disabled using a combination of the
7010** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
7011** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
7012** <li> An alternative page cache implementation is specified using
7013** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
7014** <li> The page cache allocates from its own memory pool supplied
7015** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
7016** from the heap.
7017** </ul>)^
7019** The circumstances under which SQLite will enforce the heap limits may
7020** changes in future releases of SQLite.
7022SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
7023SQLITE_API sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N);
7026** CAPI3REF: Deprecated Soft Heap Limit Interface
7029** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
7030** interface. This routine is provided for historical compatibility
7031** only. All new applications should use the
7032** [sqlite3_soft_heap_limit64()] interface rather than this one.
7034SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
7038** CAPI3REF: Extract Metadata About A Column Of A Table
7039** METHOD: sqlite3
7041** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
7042** information about column C of table T in database D
7043** on [database connection] X.)^ ^The sqlite3_table_column_metadata()
7044** interface returns SQLITE_OK and fills in the non-NULL pointers in
7045** the final five arguments with appropriate values if the specified
7046** column exists. ^The sqlite3_table_column_metadata() interface returns
7047** SQLITE_ERROR if the specified column does not exist.
7048** ^If the column-name parameter to sqlite3_table_column_metadata() is a
7049** NULL pointer, then this routine simply checks for the existence of the
7050** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
7051** does not. If the table name parameter T in a call to
7052** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
7053** undefined behavior.
7055** ^The column is identified by the second, third and fourth parameters to
7056** this function. ^(The second parameter is either the name of the database
7057** (i.e. "main", "temp", or an attached database) containing the specified
7058** table or NULL.)^ ^If it is NULL, then all attached databases are searched
7059** for the table using the same algorithm used by the database engine to
7060** resolve unqualified table references.
7062** ^The third and fourth parameters to this function are the table and column
7063** name of the desired column, respectively.
7065** ^Metadata is returned by writing to the memory locations passed as the 5th
7066** and subsequent parameters to this function. ^Any of these arguments may be
7067** NULL, in which case the corresponding element of metadata is omitted.
7069** ^(<blockquote>
7070** <table border="1">
7071** <tr><th> Parameter <th> Output<br>Type <th> Description
7073** <tr><td> 5th <td> const char* <td> Data type
7074** <tr><td> 6th <td> const char* <td> Name of default collation sequence
7075** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
7076** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
7077** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT]
7078** </table>
7079** </blockquote>)^
7081** ^The memory pointed to by the character pointers returned for the
7082** declaration type and collation sequence is valid until the next
7083** call to any SQLite API function.
7085** ^If the specified table is actually a view, an [error code] is returned.
7087** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
7088** is not a [WITHOUT ROWID] table and an
7089** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
7090** parameters are set for the explicitly declared column. ^(If there is no
7091** [INTEGER PRIMARY KEY] column, then the outputs
7092** for the [rowid] are set as follows:
7094** <pre>
7095** data type: "INTEGER"
7096** collation sequence: "BINARY"
7097** not null: 0
7098** primary key: 1
7099** auto increment: 0
7100** </pre>)^
7102** ^This function causes all database schemas to be read from disk and
7103** parsed, if that has not already been done, and returns an error if
7104** any errors are encountered while loading the schema.
7106SQLITE_API int sqlite3_table_column_metadata(
7107 sqlite3 *db, /* Connection handle */
7108 const char *zDbName, /* Database name or NULL */
7109 const char *zTableName, /* Table name */
7110 const char *zColumnName, /* Column name */
7111 char const **pzDataType, /* OUTPUT: Declared data type */
7112 char const **pzCollSeq, /* OUTPUT: Collation sequence name */
7113 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
7114 int *pPrimaryKey, /* OUTPUT: True if column part of PK */
7115 int *pAutoinc /* OUTPUT: True if column is auto-increment */
7119** CAPI3REF: Load An Extension
7120** METHOD: sqlite3
7122** ^This interface loads an SQLite extension library from the named file.
7124** ^The sqlite3_load_extension() interface attempts to load an
7125** [SQLite extension] library contained in the file zFile. If
7126** the file cannot be loaded directly, attempts are made to load
7127** with various operating-system specific extensions added.
7128** So for example, if "samplelib" cannot be loaded, then names like
7129** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
7130** be tried also.
7132** ^The entry point is zProc.
7133** ^(zProc may be 0, in which case SQLite will try to come up with an
7134** entry point name on its own. It first tries "sqlite3_extension_init".
7135** If that does not work, it constructs a name "sqlite3_X_init" where the
7136** X is consists of the lower-case equivalent of all ASCII alphabetic
7137** characters in the filename from the last "/" to the first following
7138** "." and omitting any initial "lib".)^
7139** ^The sqlite3_load_extension() interface returns
7140** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
7141** ^If an error occurs and pzErrMsg is not 0, then the
7142** [sqlite3_load_extension()] interface shall attempt to
7143** fill *pzErrMsg with error message text stored in memory
7144** obtained from [sqlite3_malloc()]. The calling function
7145** should free this memory by calling [sqlite3_free()].
7147** ^Extension loading must be enabled using
7148** [sqlite3_enable_load_extension()] or
7149** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
7150** prior to calling this API,
7151** otherwise an error will be returned.
7153** <b>Security warning:</b> It is recommended that the
7154** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
7155** interface. The use of the [sqlite3_enable_load_extension()] interface
7156** should be avoided. This will keep the SQL function [load_extension()]
7157** disabled and prevent SQL injections from giving attackers
7158** access to extension loading capabilities.
7160** See also the [load_extension() SQL function].
7162SQLITE_API int sqlite3_load_extension(
7163 sqlite3 *db, /* Load the extension into this database connection */
7164 const char *zFile, /* Name of the shared library containing extension */
7165 const char *zProc, /* Entry point. Derived from zFile if 0 */
7166 char **pzErrMsg /* Put error message here if not 0 */
7170** CAPI3REF: Enable Or Disable Extension Loading
7171** METHOD: sqlite3
7173** ^So as not to open security holes in older applications that are
7174** unprepared to deal with [extension loading], and as a means of disabling
7175** [extension loading] while evaluating user-entered SQL, the following API
7176** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
7178** ^Extension loading is off by default.
7179** ^Call the sqlite3_enable_load_extension() routine with onoff==1
7180** to turn extension loading on and call it with onoff==0 to turn
7181** it back off again.
7183** ^This interface enables or disables both the C-API
7184** [sqlite3_load_extension()] and the SQL function [load_extension()].
7185** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
7186** to enable or disable only the C-API.)^
7188** <b>Security warning:</b> It is recommended that extension loading
7189** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
7190** rather than this interface, so the [load_extension()] SQL function
7191** remains disabled. This will prevent SQL injections from giving attackers
7192** access to extension loading capabilities.
7194SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
7197** CAPI3REF: Automatically Load Statically Linked Extensions
7199** ^This interface causes the xEntryPoint() function to be invoked for
7200** each new [database connection] that is created. The idea here is that
7201** xEntryPoint() is the entry point for a statically linked [SQLite extension]
7202** that is to be automatically loaded into all new database connections.
7204** ^(Even though the function prototype shows that xEntryPoint() takes
7205** no arguments and returns void, SQLite invokes xEntryPoint() with three
7206** arguments and expects an integer result as if the signature of the
7207** entry point where as follows:
7209** <blockquote><pre>
7210** &nbsp; int xEntryPoint(
7211** &nbsp; sqlite3 *db,
7212** &nbsp; const char **pzErrMsg,
7213** &nbsp; const struct sqlite3_api_routines *pThunk
7214** &nbsp; );
7215** </pre></blockquote>)^
7217** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
7218** point to an appropriate error message (obtained from [sqlite3_mprintf()])
7219** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg
7220** is NULL before calling the xEntryPoint(). ^SQLite will invoke
7221** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any
7222** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
7223** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
7225** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
7226** on the list of automatic extensions is a harmless no-op. ^No entry point
7227** will be called more than once for each database connection that is opened.
7229** See also: [sqlite3_reset_auto_extension()]
7230** and [sqlite3_cancel_auto_extension()]
7232SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));
7235** CAPI3REF: Cancel Automatic Extension Loading
7237** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
7238** initialization routine X that was registered using a prior call to
7239** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)]
7240** routine returns 1 if initialization routine X was successfully
7241** unregistered and it returns 0 if X was not on the list of initialization
7242** routines.
7244SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
7247** CAPI3REF: Reset Automatic Extension Loading
7249** ^This interface disables all automatic extensions previously
7250** registered using [sqlite3_auto_extension()].
7252SQLITE_API void sqlite3_reset_auto_extension(void);
7255** The interface to the virtual-table mechanism is currently considered
7256** to be experimental. The interface might change in incompatible ways.
7257** If this is a problem for you, do not use the interface at this time.
7259** When the virtual-table mechanism stabilizes, we will declare the
7260** interface fixed, support it indefinitely, and remove this comment.
7264** Structures used by the virtual table interface
7266typedef struct sqlite3_vtab sqlite3_vtab;
7267typedef struct sqlite3_index_info sqlite3_index_info;
7268typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
7269typedef struct sqlite3_module sqlite3_module;
7272** CAPI3REF: Virtual Table Object
7273** KEYWORDS: sqlite3_module {virtual table module}
7275** This structure, sometimes called a "virtual table module",
7276** defines the implementation of a [virtual table].
7277** This structure consists mostly of methods for the module.
7279** ^A virtual table module is created by filling in a persistent
7280** instance of this structure and passing a pointer to that instance
7281** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
7282** ^The registration remains valid until it is replaced by a different
7283** module or until the [database connection] closes. The content
7284** of this structure must not change while it is registered with
7285** any database connection.
7287struct sqlite3_module {
7288 int iVersion;
7289 int (*xCreate)(sqlite3*, void *pAux,
7290 int argc, const char *const*argv,
7291 sqlite3_vtab **ppVTab, char**);
7292 int (*xConnect)(sqlite3*, void *pAux,
7293 int argc, const char *const*argv,
7294 sqlite3_vtab **ppVTab, char**);
7295 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
7296 int (*xDisconnect)(sqlite3_vtab *pVTab);
7297 int (*xDestroy)(sqlite3_vtab *pVTab);
7298 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
7299 int (*xClose)(sqlite3_vtab_cursor*);
7300 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
7301 int argc, sqlite3_value **argv);
7302 int (*xNext)(sqlite3_vtab_cursor*);
7303 int (*xEof)(sqlite3_vtab_cursor*);
7304 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
7305 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
7306 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
7307 int (*xBegin)(sqlite3_vtab *pVTab);
7308 int (*xSync)(sqlite3_vtab *pVTab);
7309 int (*xCommit)(sqlite3_vtab *pVTab);
7310 int (*xRollback)(sqlite3_vtab *pVTab);
7311 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
7312 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
7313 void **ppArg);
7314 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
7315 /* The methods above are in version 1 of the sqlite_module object. Those
7316 ** below are for version 2 and greater. */
7317 int (*xSavepoint)(sqlite3_vtab *pVTab, int);
7318 int (*xRelease)(sqlite3_vtab *pVTab, int);
7319 int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
7320 /* The methods above are in versions 1 and 2 of the sqlite_module object.
7321 ** Those below are for version 3 and greater. */
7322 int (*xShadowName)(const char*);
7326** CAPI3REF: Virtual Table Indexing Information
7327** KEYWORDS: sqlite3_index_info
7329** The sqlite3_index_info structure and its substructures is used as part
7330** of the [virtual table] interface to
7331** pass information into and receive the reply from the [xBestIndex]
7332** method of a [virtual table module]. The fields under **Inputs** are the
7333** inputs to xBestIndex and are read-only. xBestIndex inserts its
7334** results into the **Outputs** fields.
7336** ^(The aConstraint[] array records WHERE clause constraints of the form:
7338** <blockquote>column OP expr</blockquote>
7340** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^ ^(The particular operator is
7341** stored in aConstraint[].op using one of the
7343** ^(The index of the column is stored in
7344** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the
7345** expr on the right-hand side can be evaluated (and thus the constraint
7346** is usable) and false if it cannot.)^
7348** ^The optimizer automatically inverts terms of the form "expr OP column"
7349** and makes other simplifications to the WHERE clause in an attempt to
7350** get as many WHERE clause terms into the form shown above as possible.
7351** ^The aConstraint[] array only reports WHERE clause terms that are
7352** relevant to the particular virtual table being queried.
7354** ^Information about the ORDER BY clause is stored in aOrderBy[].
7355** ^Each term of aOrderBy records a column of the ORDER BY clause.
7357** The colUsed field indicates which columns of the virtual table may be
7358** required by the current scan. Virtual table columns are numbered from
7359** zero in the order in which they appear within the CREATE TABLE statement
7360** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
7361** the corresponding bit is set within the colUsed mask if the column may be
7362** required by SQLite. If the table has at least 64 columns and any column
7363** to the right of the first 63 is required, then bit 63 of colUsed is also
7364** set. In other words, column iCol may be required if the expression
7365** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
7366** non-zero.
7368** The [xBestIndex] method must fill aConstraintUsage[] with information
7369** about what parameters to pass to xFilter. ^If argvIndex>0 then
7370** the right-hand side of the corresponding aConstraint[] is evaluated
7371** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit
7372** is true, then the constraint is assumed to be fully handled by the
7373** virtual table and might not be checked again by the byte code.)^ ^(The
7374** aConstraintUsage[].omit flag is an optimization hint. When the omit flag
7375** is left in its default setting of false, the constraint will always be
7376** checked separately in byte code. If the omit flag is change to true, then
7377** the constraint may or may not be checked in byte code. In other words,
7378** when the omit flag is true there is no guarantee that the constraint will
7379** not be checked again using byte code.)^
7381** ^The idxNum and idxPtr values are recorded and passed into the
7382** [xFilter] method.
7383** ^[sqlite3_free()] is used to free idxPtr if and only if
7384** needToFreeIdxPtr is true.
7386** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
7387** the correct order to satisfy the ORDER BY clause so that no separate
7388** sorting step is required.
7390** ^The estimatedCost value is an estimate of the cost of a particular
7391** strategy. A cost of N indicates that the cost of the strategy is similar
7392** to a linear scan of an SQLite table with N rows. A cost of log(N)
7393** indicates that the expense of the operation is similar to that of a
7394** binary search on a unique indexed field of an SQLite table with N rows.
7396** ^The estimatedRows value is an estimate of the number of rows that
7397** will be returned by the strategy.
7399** The xBestIndex method may optionally populate the idxFlags field with a
7400** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
7401** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
7402** assumes that the strategy may visit at most one row.
7404** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
7405** SQLite also assumes that if a call to the xUpdate() method is made as
7406** part of the same statement to delete or update a virtual table row and the
7407** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
7408** any database changes. In other words, if the xUpdate() returns
7409** SQLITE_CONSTRAINT, the database contents must be exactly as they were
7410** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
7411** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
7412** the xUpdate method are automatically rolled back by SQLite.
7414** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
7415** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
7416** If a virtual table extension is
7417** used with an SQLite version earlier than 3.8.2, the results of attempting
7418** to read or write the estimatedRows field are undefined (but are likely
7419** to include crashing the application). The estimatedRows field should
7420** therefore only be used if [sqlite3_libversion_number()] returns a
7421** value greater than or equal to 3008002. Similarly, the idxFlags field
7422** was added for [version 3.9.0] ([dateof:3.9.0]).
7423** It may therefore only be used if
7424** sqlite3_libversion_number() returns a value greater than or equal to
7425** 3009000.
7427struct sqlite3_index_info {
7428 /* Inputs */
7429 int nConstraint; /* Number of entries in aConstraint */
7430 struct sqlite3_index_constraint {
7431 int iColumn; /* Column constrained. -1 for ROWID */
7432 unsigned char op; /* Constraint operator */
7433 unsigned char usable; /* True if this constraint is usable */
7434 int iTermOffset; /* Used internally - xBestIndex should ignore */
7435 } *aConstraint; /* Table of WHERE clause constraints */
7436 int nOrderBy; /* Number of terms in the ORDER BY clause */
7437 struct sqlite3_index_orderby {
7438 int iColumn; /* Column number */
7439 unsigned char desc; /* True for DESC. False for ASC. */
7440 } *aOrderBy; /* The ORDER BY clause */
7441 /* Outputs */
7442 struct sqlite3_index_constraint_usage {
7443 int argvIndex; /* if >0, constraint is part of argv to xFilter */
7444 unsigned char omit; /* Do not code a test for this constraint */
7445 } *aConstraintUsage;
7446 int idxNum; /* Number used to identify the index */
7447 char *idxStr; /* String, possibly obtained from sqlite3_malloc */
7448 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
7449 int orderByConsumed; /* True if output is already ordered */
7450 double estimatedCost; /* Estimated cost of using this index */
7451 /* Fields below are only available in SQLite 3.8.2 and later */
7452 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */
7453 /* Fields below are only available in SQLite 3.9.0 and later */
7454 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */
7455 /* Fields below are only available in SQLite 3.10.0 and later */
7456 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */
7460** CAPI3REF: Virtual Table Scan Flags
7462** Virtual table implementations are allowed to set the
7463** [sqlite3_index_info].idxFlags field to some combination of
7464** these bits.
7466#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */
7469** CAPI3REF: Virtual Table Constraint Operator Codes
7471** These macros define the allowed values for the
7472** [sqlite3_index_info].aConstraint[].op field. Each value represents
7473** an operator that is part of a constraint term in the WHERE clause of
7474** a query that uses a [virtual table].
7476** ^The left-hand operand of the operator is given by the corresponding
7477** aConstraint[].iColumn field. ^An iColumn of -1 indicates the left-hand
7478** operand is the rowid.
7480** operators have no left-hand operand, and so for those operators the
7481** corresponding aConstraint[].iColumn is meaningless and should not be
7482** used.
7484** All operator values from SQLITE_INDEX_CONSTRAINT_FUNCTION through
7485** value 255 are reserved to represent functions that are overloaded
7486** by the [xFindFunction|xFindFunction method] of the virtual table
7487** implementation.
7489** The right-hand operands for each constraint might be accessible using
7490** the [sqlite3_vtab_rhs_value()] interface. Usually the right-hand
7491** operand is only available if it appears as a single constant literal
7492** in the input SQL. If the right-hand operand is another column or an
7493** expression (even a constant expression) or a parameter, then the
7494** sqlite3_vtab_rhs_value() probably will not be able to extract it.
7496** SQLITE_INDEX_CONSTRAINT_ISNOTNULL operators have no right-hand operand
7497** and hence calls to sqlite3_vtab_rhs_value() for those operators will
7498** always return SQLITE_NOTFOUND.
7500** The collating sequence to be used for comparison can be found using
7501** the [sqlite3_vtab_collation()] interface. For most real-world virtual
7502** tables, the collating sequence of constraints does not matter (for example
7503** because the constraints are numeric) and so the sqlite3_vtab_collation()
7504** interface is no commonly needed.
7525** CAPI3REF: Register A Virtual Table Implementation
7526** METHOD: sqlite3
7528** ^These routines are used to register a new [virtual table module] name.
7529** ^Module names must be registered before
7530** creating a new [virtual table] using the module and before using a
7531** preexisting [virtual table] for the module.
7533** ^The module name is registered on the [database connection] specified
7534** by the first parameter. ^The name of the module is given by the
7535** second parameter. ^The third parameter is a pointer to
7536** the implementation of the [virtual table module]. ^The fourth
7537** parameter is an arbitrary client data pointer that is passed through
7538** into the [xCreate] and [xConnect] methods of the virtual table module
7539** when a new virtual table is be being created or reinitialized.
7541** ^The sqlite3_create_module_v2() interface has a fifth parameter which
7542** is a pointer to a destructor for the pClientData. ^SQLite will
7543** invoke the destructor function (if it is not NULL) when SQLite
7544** no longer needs the pClientData pointer. ^The destructor will also
7545** be invoked if the call to sqlite3_create_module_v2() fails.
7546** ^The sqlite3_create_module()
7547** interface is equivalent to sqlite3_create_module_v2() with a NULL
7548** destructor.
7550** ^If the third parameter (the pointer to the sqlite3_module object) is
7551** NULL then no new module is created and any existing modules with the
7552** same name are dropped.
7554** See also: [sqlite3_drop_modules()]
7556SQLITE_API int sqlite3_create_module(
7557 sqlite3 *db, /* SQLite connection to register module with */
7558 const char *zName, /* Name of the module */
7559 const sqlite3_module *p, /* Methods for the module */
7560 void *pClientData /* Client data for xCreate/xConnect */
7562SQLITE_API int sqlite3_create_module_v2(
7563 sqlite3 *db, /* SQLite connection to register module with */
7564 const char *zName, /* Name of the module */
7565 const sqlite3_module *p, /* Methods for the module */
7566 void *pClientData, /* Client data for xCreate/xConnect */
7567 void(*xDestroy)(void*) /* Module destructor function */
7571** CAPI3REF: Remove Unnecessary Virtual Table Implementations
7572** METHOD: sqlite3
7574** ^The sqlite3_drop_modules(D,L) interface removes all virtual
7575** table modules from database connection D except those named on list L.
7576** The L parameter must be either NULL or a pointer to an array of pointers
7577** to strings where the array is terminated by a single NULL pointer.
7578** ^If the L parameter is NULL, then all virtual table modules are removed.
7580** See also: [sqlite3_create_module()]
7582SQLITE_API int sqlite3_drop_modules(
7583 sqlite3 *db, /* Remove modules from this connection */
7584 const char **azKeep /* Except, do not remove the ones named here */
7588** CAPI3REF: Virtual Table Instance Object
7589** KEYWORDS: sqlite3_vtab
7591** Every [virtual table module] implementation uses a subclass
7592** of this object to describe a particular instance
7593** of the [virtual table]. Each subclass will
7594** be tailored to the specific needs of the module implementation.
7595** The purpose of this superclass is to define certain fields that are
7596** common to all module implementations.
7598** ^Virtual tables methods can set an error message by assigning a
7599** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should
7600** take care that any prior string is freed by a call to [sqlite3_free()]
7601** prior to assigning a new string to zErrMsg. ^After the error message
7602** is delivered up to the client application, the string will be automatically
7603** freed by sqlite3_free() and the zErrMsg field will be zeroed.
7605struct sqlite3_vtab {
7606 const sqlite3_module *pModule; /* The module for this virtual table */
7607 int nRef; /* Number of open cursors */
7608 char *zErrMsg; /* Error message from sqlite3_mprintf() */
7609 /* Virtual table implementations will typically add additional fields */
7613** CAPI3REF: Virtual Table Cursor Object
7614** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
7616** Every [virtual table module] implementation uses a subclass of the
7617** following structure to describe cursors that point into the
7618** [virtual table] and are used
7619** to loop through the virtual table. Cursors are created using the
7620** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
7621** by the [sqlite3_module.xClose | xClose] method. Cursors are used
7622** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
7623** of the module. Each module implementation will define
7624** the content of a cursor structure to suit its own needs.
7626** This superclass exists in order to define fields of the cursor that
7627** are common to all implementations.
7629struct sqlite3_vtab_cursor {
7630 sqlite3_vtab *pVtab; /* Virtual table of this cursor */
7631 /* Virtual table implementations will typically add additional fields */
7635** CAPI3REF: Declare The Schema Of A Virtual Table
7637** ^The [xCreate] and [xConnect] methods of a
7638** [virtual table module] call this interface
7639** to declare the format (the names and datatypes of the columns) of
7640** the virtual tables they implement.
7642SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
7645** CAPI3REF: Overload A Function For A Virtual Table
7646** METHOD: sqlite3
7648** ^(Virtual tables can provide alternative implementations of functions
7649** using the [xFindFunction] method of the [virtual table module].
7650** But global versions of those functions
7651** must exist in order to be overloaded.)^
7653** ^(This API makes sure a global version of a function with a particular
7654** name and number of parameters exists. If no such function exists
7655** before this API is called, a new function is created.)^ ^The implementation
7656** of the new function always causes an exception to be thrown. So
7657** the new function is not good for anything by itself. Its only
7658** purpose is to be a placeholder function that can be overloaded
7659** by a [virtual table].
7661SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
7664** The interface to the virtual-table mechanism defined above (back up
7665** to a comment remarkably similar to this one) is currently considered
7666** to be experimental. The interface might change in incompatible ways.
7667** If this is a problem for you, do not use the interface at this time.
7669** When the virtual-table mechanism stabilizes, we will declare the
7670** interface fixed, support it indefinitely, and remove this comment.
7674** CAPI3REF: A Handle To An Open BLOB
7675** KEYWORDS: {BLOB handle} {BLOB handles}
7677** An instance of this object represents an open BLOB on which
7678** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
7679** ^Objects of this type are created by [sqlite3_blob_open()]
7680** and destroyed by [sqlite3_blob_close()].
7681** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
7682** can be used to read or write small subsections of the BLOB.
7683** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
7685typedef struct sqlite3_blob sqlite3_blob;
7688** CAPI3REF: Open A BLOB For Incremental I/O
7689** METHOD: sqlite3
7690** CONSTRUCTOR: sqlite3_blob
7692** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
7693** in row iRow, column zColumn, table zTable in database zDb;
7694** in other words, the same BLOB that would be selected by:
7696** <pre>
7697** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
7698** </pre>)^
7700** ^(Parameter zDb is not the filename that contains the database, but
7701** rather the symbolic name of the database. For attached databases, this is
7702** the name that appears after the AS keyword in the [ATTACH] statement.
7703** For the main database file, the database name is "main". For TEMP
7704** tables, the database name is "temp".)^
7706** ^If the flags parameter is non-zero, then the BLOB is opened for read
7707** and write access. ^If the flags parameter is zero, the BLOB is opened for
7708** read-only access.
7710** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
7711** in *ppBlob. Otherwise an [error code] is returned and, unless the error
7712** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
7713** the API is not misused, it is always safe to call [sqlite3_blob_close()]
7714** on *ppBlob after this function it returns.
7716** This function fails with SQLITE_ERROR if any of the following are true:
7717** <ul>
7718** <li> ^(Database zDb does not exist)^,
7719** <li> ^(Table zTable does not exist within database zDb)^,
7720** <li> ^(Table zTable is a WITHOUT ROWID table)^,
7721** <li> ^(Column zColumn does not exist)^,
7722** <li> ^(Row iRow is not present in the table)^,
7723** <li> ^(The specified column of row iRow contains a value that is not
7724** a TEXT or BLOB value)^,
7725** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
7726** constraint and the blob is being opened for read/write access)^,
7727** <li> ^([foreign key constraints | Foreign key constraints] are enabled,
7728** column zColumn is part of a [child key] definition and the blob is
7729** being opened for read/write access)^.
7730** </ul>
7732** ^Unless it returns SQLITE_MISUSE, this function sets the
7733** [database connection] error code and message accessible via
7734** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
7736** A BLOB referenced by sqlite3_blob_open() may be read using the
7737** [sqlite3_blob_read()] interface and modified by using
7738** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a
7739** different row of the same table using the [sqlite3_blob_reopen()]
7740** interface. However, the column, table, or database of a [BLOB handle]
7741** cannot be changed after the [BLOB handle] is opened.
7743** ^(If the row that a BLOB handle points to is modified by an
7744** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
7745** then the BLOB handle is marked as "expired".
7746** This is true if any column of the row is changed, even a column
7747** other than the one the BLOB handle is open on.)^
7748** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
7749** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
7750** ^(Changes written into a BLOB prior to the BLOB expiring are not
7751** rolled back by the expiration of the BLOB. Such changes will eventually
7752** commit if the transaction continues to completion.)^
7754** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
7755** the opened blob. ^The size of a blob may not be changed by this
7756** interface. Use the [UPDATE] SQL command to change the size of a
7757** blob.
7759** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
7760** and the built-in [zeroblob] SQL function may be used to create a
7761** zero-filled blob to read or write using the incremental-blob interface.
7763** To avoid a resource leak, every open [BLOB handle] should eventually
7764** be released by a call to [sqlite3_blob_close()].
7766** See also: [sqlite3_blob_close()],
7767** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
7768** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
7770SQLITE_API int sqlite3_blob_open(
7771 sqlite3*,
7772 const char *zDb,
7773 const char *zTable,
7774 const char *zColumn,
7775 sqlite3_int64 iRow,
7776 int flags,
7777 sqlite3_blob **ppBlob
7781** CAPI3REF: Move a BLOB Handle to a New Row
7782** METHOD: sqlite3_blob
7784** ^This function is used to move an existing [BLOB handle] so that it points
7785** to a different row of the same database table. ^The new row is identified
7786** by the rowid value passed as the second argument. Only the row can be
7787** changed. ^The database, table and column on which the blob handle is open
7788** remain the same. Moving an existing [BLOB handle] to a new row is
7789** faster than closing the existing handle and opening a new one.
7791** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
7792** it must exist and there must be either a blob or text value stored in
7793** the nominated column.)^ ^If the new row is not present in the table, or if
7794** it does not contain a blob or text value, or if another error occurs, an
7795** SQLite error code is returned and the blob handle is considered aborted.
7796** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
7797** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
7798** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
7799** always returns zero.
7801** ^This function sets the database handle error code and message.
7803SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
7806** CAPI3REF: Close A BLOB Handle
7807** DESTRUCTOR: sqlite3_blob
7809** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
7810** unconditionally. Even if this routine returns an error code, the
7811** handle is still closed.)^
7813** ^If the blob handle being closed was opened for read-write access, and if
7814** the database is in auto-commit mode and there are no other open read-write
7815** blob handles or active write statements, the current transaction is
7816** committed. ^If an error occurs while committing the transaction, an error
7817** code is returned and the transaction rolled back.
7819** Calling this function with an argument that is not a NULL pointer or an
7820** open blob handle results in undefined behaviour. ^Calling this routine
7821** with a null pointer (such as would be returned by a failed call to
7822** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
7823** is passed a valid open blob handle, the values returned by the
7824** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
7826SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
7829** CAPI3REF: Return The Size Of An Open BLOB
7830** METHOD: sqlite3_blob
7832** ^Returns the size in bytes of the BLOB accessible via the
7833** successfully opened [BLOB handle] in its only argument. ^The
7834** incremental blob I/O routines can only read or overwriting existing
7835** blob content; they cannot change the size of a blob.
7837** This routine only works on a [BLOB handle] which has been created
7838** by a prior successful call to [sqlite3_blob_open()] and which has not
7839** been closed by [sqlite3_blob_close()]. Passing any other pointer in
7840** to this routine results in undefined and probably undesirable behavior.
7842SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
7845** CAPI3REF: Read Data From A BLOB Incrementally
7846** METHOD: sqlite3_blob
7848** ^(This function is used to read data from an open [BLOB handle] into a
7849** caller-supplied buffer. N bytes of data are copied into buffer Z
7850** from the open BLOB, starting at offset iOffset.)^
7852** ^If offset iOffset is less than N bytes from the end of the BLOB,
7853** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is
7854** less than zero, [SQLITE_ERROR] is returned and no data is read.
7855** ^The size of the blob (and hence the maximum value of N+iOffset)
7856** can be determined using the [sqlite3_blob_bytes()] interface.
7858** ^An attempt to read from an expired [BLOB handle] fails with an
7859** error code of [SQLITE_ABORT].
7861** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
7862** Otherwise, an [error code] or an [extended error code] is returned.)^
7864** This routine only works on a [BLOB handle] which has been created
7865** by a prior successful call to [sqlite3_blob_open()] and which has not
7866** been closed by [sqlite3_blob_close()]. Passing any other pointer in
7867** to this routine results in undefined and probably undesirable behavior.
7869** See also: [sqlite3_blob_write()].
7871SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
7874** CAPI3REF: Write Data Into A BLOB Incrementally
7875** METHOD: sqlite3_blob
7877** ^(This function is used to write data into an open [BLOB handle] from a
7878** caller-supplied buffer. N bytes of data are copied from the buffer Z
7879** into the open BLOB, starting at offset iOffset.)^
7881** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
7882** Otherwise, an [error code] or an [extended error code] is returned.)^
7883** ^Unless SQLITE_MISUSE is returned, this function sets the
7884** [database connection] error code and message accessible via
7885** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
7887** ^If the [BLOB handle] passed as the first argument was not opened for
7888** writing (the flags parameter to [sqlite3_blob_open()] was zero),
7889** this function returns [SQLITE_READONLY].
7891** This function may only modify the contents of the BLOB; it is
7892** not possible to increase the size of a BLOB using this API.
7893** ^If offset iOffset is less than N bytes from the end of the BLOB,
7894** [SQLITE_ERROR] is returned and no data is written. The size of the
7895** BLOB (and hence the maximum value of N+iOffset) can be determined
7896** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
7897** than zero [SQLITE_ERROR] is returned and no data is written.
7899** ^An attempt to write to an expired [BLOB handle] fails with an
7900** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred
7901** before the [BLOB handle] expired are not rolled back by the
7902** expiration of the handle, though of course those changes might
7903** have been overwritten by the statement that expired the BLOB handle
7904** or by other independent statements.
7906** This routine only works on a [BLOB handle] which has been created
7907** by a prior successful call to [sqlite3_blob_open()] and which has not
7908** been closed by [sqlite3_blob_close()]. Passing any other pointer in
7909** to this routine results in undefined and probably undesirable behavior.
7911** See also: [sqlite3_blob_read()].
7913SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
7916** CAPI3REF: Virtual File System Objects
7918** A virtual filesystem (VFS) is an [sqlite3_vfs] object
7919** that SQLite uses to interact
7920** with the underlying operating system. Most SQLite builds come with a
7921** single default VFS that is appropriate for the host computer.
7922** New VFSes can be registered and existing VFSes can be unregistered.
7923** The following interfaces are provided.
7925** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
7926** ^Names are case sensitive.
7927** ^Names are zero-terminated UTF-8 strings.
7928** ^If there is no match, a NULL pointer is returned.
7929** ^If zVfsName is NULL then the default VFS is returned.
7931** ^New VFSes are registered with sqlite3_vfs_register().
7932** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
7933** ^The same VFS can be registered multiple times without injury.
7934** ^To make an existing VFS into the default VFS, register it again
7935** with the makeDflt flag set. If two different VFSes with the
7936** same name are registered, the behavior is undefined. If a
7937** VFS is registered with a name that is NULL or an empty string,
7938** then the behavior is undefined.
7940** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
7941** ^(If the default VFS is unregistered, another VFS is chosen as
7942** the default. The choice for the new VFS is arbitrary.)^
7944SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
7945SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
7946SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
7949** CAPI3REF: Mutexes
7951** The SQLite core uses these routines for thread
7952** synchronization. Though they are intended for internal
7953** use by SQLite, code that links against SQLite is
7954** permitted to use any of these routines.
7956** The SQLite source code contains multiple implementations
7957** of these mutex routines. An appropriate implementation
7958** is selected automatically at compile-time. The following
7959** implementations are available in the SQLite core:
7961** <ul>
7963** <li> SQLITE_MUTEX_W32
7965** </ul>
7967** The SQLITE_MUTEX_NOOP implementation is a set of routines
7968** that does no real locking and is appropriate for use in
7969** a single-threaded application. The SQLITE_MUTEX_PTHREADS and
7970** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
7971** and Windows.
7973** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
7974** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
7975** implementation is included with the library. In this case the
7976** application must supply a custom mutex implementation using the
7977** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
7978** before calling sqlite3_initialize() or any other public sqlite3_
7979** function that calls sqlite3_initialize().
7981** ^The sqlite3_mutex_alloc() routine allocates a new
7982** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
7983** routine returns NULL if it is unable to allocate the requested
7984** mutex. The argument to sqlite3_mutex_alloc() must one of these
7985** integer constants:
7987** <ul>
8002** </ul>
8004** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
8005** cause sqlite3_mutex_alloc() to create
8006** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
8007** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
8008** The mutex implementation does not need to make a distinction
8009** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
8010** not want to. SQLite will only request a recursive mutex in
8011** cases where it really needs one. If a faster non-recursive mutex
8012** implementation is available on the host platform, the mutex subsystem
8013** might return such a mutex in response to SQLITE_MUTEX_FAST.
8015** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
8017** a pointer to a static preexisting mutex. ^Nine static mutexes are
8018** used by the current version of SQLite. Future versions of SQLite
8019** may add additional static mutexes. Static mutexes are for internal
8020** use by SQLite only. Applications that use SQLite mutexes should
8021** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
8024** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
8025** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
8026** returns a different mutex on every call. ^For the static
8027** mutex types, the same mutex is returned on every call that has
8028** the same type number.
8030** ^The sqlite3_mutex_free() routine deallocates a previously
8031** allocated dynamic mutex. Attempting to deallocate a static
8032** mutex results in undefined behavior.
8034** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
8035** to enter a mutex. ^If another thread is already within the mutex,
8036** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
8037** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
8038** upon successful entry. ^(Mutexes created using
8039** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
8040** In such cases, the
8041** mutex must be exited an equal number of times before another thread
8042** can enter.)^ If the same thread tries to enter any mutex other
8043** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
8045** ^(Some systems (for example, Windows 95) do not support the operation
8046** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
8047** will always return SQLITE_BUSY. The SQLite core only ever uses
8048** sqlite3_mutex_try() as an optimization so this is acceptable
8049** behavior.)^
8051** ^The sqlite3_mutex_leave() routine exits a mutex that was
8052** previously entered by the same thread. The behavior
8053** is undefined if the mutex is not currently entered by the
8054** calling thread or is not currently allocated.
8056** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
8057** sqlite3_mutex_leave() is a NULL pointer, then all three routines
8058** behave as no-ops.
8060** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
8062SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
8063SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
8064SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
8065SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
8066SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
8069** CAPI3REF: Mutex Methods Object
8071** An instance of this structure defines the low-level routines
8072** used to allocate and use mutexes.
8074** Usually, the default mutex implementations provided by SQLite are
8075** sufficient, however the application has the option of substituting a custom
8076** implementation for specialized deployments or systems for which SQLite
8077** does not provide a suitable implementation. In this case, the application
8078** creates and populates an instance of this structure to pass
8079** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
8080** Additionally, an instance of this structure can be used as an
8081** output variable when querying the system for the current mutex
8082** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
8084** ^The xMutexInit method defined by this structure is invoked as
8085** part of system initialization by the sqlite3_initialize() function.
8086** ^The xMutexInit routine is called by SQLite exactly once for each
8087** effective call to [sqlite3_initialize()].
8089** ^The xMutexEnd method defined by this structure is invoked as
8090** part of system shutdown by the sqlite3_shutdown() function. The
8091** implementation of this method is expected to release all outstanding
8092** resources obtained by the mutex methods implementation, especially
8093** those obtained by the xMutexInit method. ^The xMutexEnd()
8094** interface is invoked exactly once for each call to [sqlite3_shutdown()].
8096** ^(The remaining seven methods defined by this structure (xMutexAlloc,
8097** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
8098** xMutexNotheld) implement the following interfaces (respectively):
8100** <ul>
8101** <li> [sqlite3_mutex_alloc()] </li>
8102** <li> [sqlite3_mutex_free()] </li>
8103** <li> [sqlite3_mutex_enter()] </li>
8104** <li> [sqlite3_mutex_try()] </li>
8105** <li> [sqlite3_mutex_leave()] </li>
8106** <li> [sqlite3_mutex_held()] </li>
8107** <li> [sqlite3_mutex_notheld()] </li>
8108** </ul>)^
8110** The only difference is that the public sqlite3_XXX functions enumerated
8111** above silently ignore any invocations that pass a NULL pointer instead
8112** of a valid mutex handle. The implementations of the methods defined
8113** by this structure are not required to handle this case. The results
8114** of passing a NULL pointer instead of a valid mutex handle are undefined
8115** (i.e. it is acceptable to provide an implementation that segfaults if
8116** it is passed a NULL pointer).
8118** The xMutexInit() method must be threadsafe. It must be harmless to
8119** invoke xMutexInit() multiple times within the same process and without
8120** intervening calls to xMutexEnd(). Second and subsequent calls to
8121** xMutexInit() must be no-ops.
8123** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
8124** and its associates). Similarly, xMutexAlloc() must not use SQLite memory
8125** allocation for a static mutex. ^However xMutexAlloc() may use SQLite
8126** memory allocation for a fast or recursive mutex.
8128** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
8129** called, but only if the prior call to xMutexInit returned SQLITE_OK.
8130** If xMutexInit fails in any way, it is expected to clean up after itself
8131** prior to returning.
8133typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
8134struct sqlite3_mutex_methods {
8135 int (*xMutexInit)(void);
8136 int (*xMutexEnd)(void);
8137 sqlite3_mutex *(*xMutexAlloc)(int);
8138 void (*xMutexFree)(sqlite3_mutex *);
8139 void (*xMutexEnter)(sqlite3_mutex *);
8140 int (*xMutexTry)(sqlite3_mutex *);
8141 void (*xMutexLeave)(sqlite3_mutex *);
8142 int (*xMutexHeld)(sqlite3_mutex *);
8143 int (*xMutexNotheld)(sqlite3_mutex *);
8147** CAPI3REF: Mutex Verification Routines
8149** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
8150** are intended for use inside assert() statements. The SQLite core
8151** never uses these routines except inside an assert() and applications
8152** are advised to follow the lead of the core. The SQLite core only
8153** provides implementations for these routines when it is compiled
8154** with the SQLITE_DEBUG flag. External mutex implementations
8155** are only required to provide these routines if SQLITE_DEBUG is
8156** defined and if NDEBUG is not defined.
8158** These routines should return true if the mutex in their argument
8159** is held or not held, respectively, by the calling thread.
8161** The implementation is not required to provide versions of these
8162** routines that actually work. If the implementation does not provide working
8163** versions of these routines, it should at least provide stubs that always
8164** return true so that one does not get spurious assertion failures.
8166** If the argument to sqlite3_mutex_held() is a NULL pointer then
8167** the routine should return 1. This seems counter-intuitive since
8168** clearly the mutex cannot be held if it does not exist. But
8169** the reason the mutex does not exist is because the build is not
8170** using mutexes. And we do not want the assert() containing the
8171** call to sqlite3_mutex_held() to fail, so a non-zero return is
8172** the appropriate thing to do. The sqlite3_mutex_notheld()
8173** interface should also return 1 when given a NULL pointer.
8175#ifndef NDEBUG
8176SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
8177SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
8181** CAPI3REF: Mutex Types
8183** The [sqlite3_mutex_alloc()] interface takes a single argument
8184** which is one of these integer constants.
8186** The set of static mutexes may change from one SQLite release to the
8187** next. Applications that override the built-in mutex logic must be
8188** prepared to accommodate additional static mutexes.
8190#define SQLITE_MUTEX_FAST 0
8193#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
8195#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
8196#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */
8197#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
8199#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
8200#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */
8201#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */
8202#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */
8203#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */
8204#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */
8205#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */
8207/* Legacy compatibility: */
8212** CAPI3REF: Retrieve the mutex for a database connection
8213** METHOD: sqlite3
8215** ^This interface returns a pointer the [sqlite3_mutex] object that
8216** serializes access to the [database connection] given in the argument
8217** when the [threading mode] is Serialized.
8218** ^If the [threading mode] is Single-thread or Multi-thread then this
8219** routine returns a NULL pointer.
8221SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
8224** CAPI3REF: Low-Level Control Of Database Files
8225** METHOD: sqlite3
8226** KEYWORDS: {file control}
8228** ^The [sqlite3_file_control()] interface makes a direct call to the
8229** xFileControl method for the [sqlite3_io_methods] object associated
8230** with a particular database identified by the second argument. ^The
8231** name of the database is "main" for the main database or "temp" for the
8232** TEMP database, or the name that appears after the AS keyword for
8233** databases that are added using the [ATTACH] SQL command.
8234** ^A NULL pointer can be used in place of "main" to refer to the
8235** main database file.
8236** ^The third and fourth parameters to this routine
8237** are passed directly through to the second and third parameters of
8238** the xFileControl method. ^The return value of the xFileControl
8239** method becomes the return value of this routine.
8241** A few opcodes for [sqlite3_file_control()] are handled directly
8242** by the SQLite core and never invoke the
8243** sqlite3_io_methods.xFileControl method.
8244** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
8245** a pointer to the underlying [sqlite3_file] object to be written into
8246** the space pointed to by the 4th parameter. The
8247** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns
8248** the [sqlite3_file] object associated with the journal file instead of
8249** the main database. The [SQLITE_FCNTL_VFS_POINTER] opcode returns
8250** a pointer to the underlying [sqlite3_vfs] object for the file.
8251** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter
8252** from the pager.
8254** ^If the second parameter (zDbName) does not match the name of any
8255** open database file, then SQLITE_ERROR is returned. ^This error
8256** code is not remembered and will not be recalled by [sqlite3_errcode()]
8257** or [sqlite3_errmsg()]. The underlying xFileControl method might
8258** also return SQLITE_ERROR. There is no way to distinguish between
8259** an incorrect zDbName and an SQLITE_ERROR return from the underlying
8260** xFileControl method.
8262** See also: [file control opcodes]
8264SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
8267** CAPI3REF: Testing Interface
8269** ^The sqlite3_test_control() interface is used to read out internal
8270** state of SQLite and to inject faults into SQLite for testing
8271** purposes. ^The first parameter is an operation code that determines
8272** the number, meaning, and operation of all subsequent parameters.
8274** This interface is not for use by applications. It exists solely
8275** for verifying the correct operation of the SQLite library. Depending
8276** on how the SQLite library is compiled, this interface might not exist.
8278** The details of the operation codes, their meanings, the parameters
8279** they take, and what they do are all subject to change without notice.
8280** Unlike most of the SQLite API, this function is not guaranteed to
8281** operate consistently from one release to the next.
8283SQLITE_API int sqlite3_test_control(int op, ...);
8286** CAPI3REF: Testing Interface Operation Codes
8288** These constants are the valid operation code parameters used
8289** as the first argument to [sqlite3_test_control()].
8291** These parameters and their meanings are subject to change
8292** without notice. These values are for testing purposes only.
8293** Applications should not use any of these parameters or the
8294** [sqlite3_test_control()] interface.
8328#define SQLITE_TESTCTRL_LAST 33 /* Largest TESTCTRL */
8331** CAPI3REF: SQL Keyword Checking
8333** These routines provide access to the set of SQL language keywords
8334** recognized by SQLite. Applications can uses these routines to determine
8335** whether or not a specific identifier needs to be escaped (for example,
8336** by enclosing in double-quotes) so as not to confuse the parser.
8338** The sqlite3_keyword_count() interface returns the number of distinct
8339** keywords understood by SQLite.
8341** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and
8342** makes *Z point to that keyword expressed as UTF8 and writes the number
8343** of bytes in the keyword into *L. The string that *Z points to is not
8344** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns
8345** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
8346** or L are NULL or invalid pointers then calls to
8347** sqlite3_keyword_name(N,Z,L) result in undefined behavior.
8349** The sqlite3_keyword_check(Z,L) interface checks to see whether or not
8350** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
8351** if it is and zero if not.
8353** The parser used by SQLite is forgiving. It is often possible to use
8354** a keyword as an identifier as long as such use does not result in a
8355** parsing ambiguity. For example, the statement
8356** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
8357** creates a new table named "BEGIN" with three columns named
8358** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid
8359** using keywords as identifiers. Common techniques used to avoid keyword
8360** name collisions include:
8361** <ul>
8362** <li> Put all identifier names inside double-quotes. This is the official
8363** SQL way to escape identifier names.
8364** <li> Put identifier names inside &#91;...&#93;. This is not standard SQL,
8365** but it is what SQL Server does and so lots of programmers use this
8366** technique.
8367** <li> Begin every identifier with the letter "Z" as no SQL keywords start
8368** with "Z".
8369** <li> Include a digit somewhere in every identifier name.
8370** </ul>