1
2/* pngconf.h - machine-configurable file for libpng
3 *
4 * libpng version 1.6.37
5 *
6 * Copyright (c) 2018-2019 Cosmin Truta
7 * Copyright (c) 1998-2002,2004,2006-2016,2018 Glenn Randers-Pehrson
8 * Copyright (c) 1996-1997 Andreas Dilger
9 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
10 *
11 * This code is released under the libpng license.
12 * For conditions of distribution and use, see the disclaimer
13 * and license in png.h
14 *
15 * Any machine specific code is near the front of this file, so if you
16 * are configuring libpng for a machine, you may want to read the section
17 * starting here down to where it starts to typedef png_color, png_text,
18 * and png_info.
19 */
20
21#ifndef PNGCONF_H
22#define PNGCONF_H
23
24#ifndef PNG_BUILDING_SYMBOL_TABLE /* else includes may cause problems */
25
26/* From libpng 1.6.0 libpng requires an ANSI X3.159-1989 ("ISOC90") compliant C
27 * compiler for correct compilation. The following header files are required by
28 * the standard. If your compiler doesn't provide these header files, or they
29 * do not match the standard, you will need to provide/improve them.
30 */
31#include <limits.h>
32#include <stddef.h>
33
34/* Library header files. These header files are all defined by ISOC90; libpng
35 * expects conformant implementations, however, an ISOC90 conformant system need
36 * not provide these header files if the functionality cannot be implemented.
37 * In this case it will be necessary to disable the relevant parts of libpng in
38 * the build of pnglibconf.h.
39 *
40 * Prior to 1.6.0 string.h was included here; the API changes in 1.6.0 to not
41 * include this unnecessary header file.
42 */
43
44#ifdef PNG_STDIO_SUPPORTED
45 /* Required for the definition of FILE: */
46# include <stdio.h>
47#endif
48
49#ifdef PNG_SETJMP_SUPPORTED
50 /* Required for the definition of jmp_buf and the declaration of longjmp: */
51# include <setjmp.h>
52#endif
53
54#ifdef PNG_CONVERT_tIME_SUPPORTED
55 /* Required for struct tm: */
56# include <time.h>
57#endif
58
59#endif /* PNG_BUILDING_SYMBOL_TABLE */
60
61/* Prior to 1.6.0, it was possible to turn off 'const' in declarations,
62 * using PNG_NO_CONST. This is no longer supported.
63 */
64#define PNG_CONST const /* backward compatibility only */
65
66/* This controls optimization of the reading of 16-bit and 32-bit
67 * values from PNG files. It can be set on a per-app-file basis: it
68 * just changes whether a macro is used when the function is called.
69 * The library builder sets the default; if read functions are not
70 * built into the library the macro implementation is forced on.
71 */
72#ifndef PNG_READ_INT_FUNCTIONS_SUPPORTED
73# define PNG_USE_READ_MACROS
74#endif
75#if !defined(PNG_NO_USE_READ_MACROS) && !defined(PNG_USE_READ_MACROS)
76# if PNG_DEFAULT_READ_MACROS
77# define PNG_USE_READ_MACROS
78# endif
79#endif
80
81/* COMPILER SPECIFIC OPTIONS.
82 *
83 * These options are provided so that a variety of difficult compilers
84 * can be used. Some are fixed at build time (e.g. PNG_API_RULE
85 * below) but still have compiler specific implementations, others
86 * may be changed on a per-file basis when compiling against libpng.
87 */
88
89/* The PNGARG macro was used in versions of libpng prior to 1.6.0 to protect
90 * against legacy (pre ISOC90) compilers that did not understand function
91 * prototypes. It is not required for modern C compilers.
92 */
93#ifndef PNGARG
94# define PNGARG(arglist) arglist
95#endif
96
97/* Function calling conventions.
98 * =============================
99 * Normally it is not necessary to specify to the compiler how to call
100 * a function - it just does it - however on x86 systems derived from
101 * Microsoft and Borland C compilers ('IBM PC', 'DOS', 'Windows' systems
102 * and some others) there are multiple ways to call a function and the
103 * default can be changed on the compiler command line. For this reason
104 * libpng specifies the calling convention of every exported function and
105 * every function called via a user supplied function pointer. This is
106 * done in this file by defining the following macros:
107 *
108 * PNGAPI Calling convention for exported functions.
109 * PNGCBAPI Calling convention for user provided (callback) functions.
110 * PNGCAPI Calling convention used by the ANSI-C library (required
111 * for longjmp callbacks and sometimes used internally to
112 * specify the calling convention for zlib).
113 *
114 * These macros should never be overridden. If it is necessary to
115 * change calling convention in a private build this can be done
116 * by setting PNG_API_RULE (which defaults to 0) to one of the values
117 * below to select the correct 'API' variants.
118 *
119 * PNG_API_RULE=0 Use PNGCAPI - the 'C' calling convention - throughout.
120 * This is correct in every known environment.
121 * PNG_API_RULE=1 Use the operating system convention for PNGAPI and
122 * the 'C' calling convention (from PNGCAPI) for
123 * callbacks (PNGCBAPI). This is no longer required
124 * in any known environment - if it has to be used
125 * please post an explanation of the problem to the
126 * libpng mailing list.
127 *
128 * These cases only differ if the operating system does not use the C
129 * calling convention, at present this just means the above cases
130 * (x86 DOS/Windows systems) and, even then, this does not apply to
131 * Cygwin running on those systems.
132 *
133 * Note that the value must be defined in pnglibconf.h so that what
134 * the application uses to call the library matches the conventions
135 * set when building the library.
136 */
137
138/* Symbol export
139 * =============
140 * When building a shared library it is almost always necessary to tell
141 * the compiler which symbols to export. The png.h macro 'PNG_EXPORT'
142 * is used to mark the symbols. On some systems these symbols can be
143 * extracted at link time and need no special processing by the compiler,
144 * on other systems the symbols are flagged by the compiler and just
145 * the declaration requires a special tag applied (unfortunately) in a
146 * compiler dependent way. Some systems can do either.
147 *
148 * A small number of older systems also require a symbol from a DLL to
149 * be flagged to the program that calls it. This is a problem because
150 * we do not know in the header file included by application code that
151 * the symbol will come from a shared library, as opposed to a statically
152 * linked one. For this reason the application must tell us by setting
153 * the magic flag PNG_USE_DLL to turn on the special processing before
154 * it includes png.h.
155 *
156 * Four additional macros are used to make this happen:
157 *
158 * PNG_IMPEXP The magic (if any) to cause a symbol to be exported from
159 * the build or imported if PNG_USE_DLL is set - compiler
160 * and system specific.
161 *
162 * PNG_EXPORT_TYPE(type) A macro that pre or appends PNG_IMPEXP to
163 * 'type', compiler specific.
164 *
165 * PNG_DLL_EXPORT Set to the magic to use during a libpng build to
166 * make a symbol exported from the DLL. Not used in the
167 * public header files; see pngpriv.h for how it is used
168 * in the libpng build.
169 *
170 * PNG_DLL_IMPORT Set to the magic to force the libpng symbols to come
171 * from a DLL - used to define PNG_IMPEXP when
172 * PNG_USE_DLL is set.
173 */
174
175/* System specific discovery.
176 * ==========================
177 * This code is used at build time to find PNG_IMPEXP, the API settings
178 * and PNG_EXPORT_TYPE(), it may also set a macro to indicate the DLL
179 * import processing is possible. On Windows systems it also sets
180 * compiler-specific macros to the values required to change the calling
181 * conventions of the various functions.
182 */
183#if defined(_Windows) || defined(_WINDOWS) || defined(WIN32) ||\
184 defined(_WIN32) || defined(__WIN32__) || defined(__CYGWIN__)
185 /* Windows system (DOS doesn't support DLLs). Includes builds under Cygwin or
186 * MinGW on any architecture currently supported by Windows. Also includes
187 * Watcom builds but these need special treatment because they are not
188 * compatible with GCC or Visual C because of different calling conventions.
189 */
190# if PNG_API_RULE == 2
191 /* If this line results in an error, either because __watcall is not
192 * understood or because of a redefine just below you cannot use *this*
193 * build of the library with the compiler you are using. *This* build was
194 * build using Watcom and applications must also be built using Watcom!
195 */
196# define PNGCAPI __watcall
197# endif
198
199# if defined(__GNUC__) || (defined(_MSC_VER) && (_MSC_VER >= 800))
200# define PNGCAPI __cdecl
201# if PNG_API_RULE == 1
202 /* If this line results in an error __stdcall is not understood and
203 * PNG_API_RULE should not have been set to '1'.
204 */
205# define PNGAPI __stdcall
206# endif
207# else
208 /* An older compiler, or one not detected (erroneously) above,
209 * if necessary override on the command line to get the correct
210 * variants for the compiler.
211 */
212# ifndef PNGCAPI
213# define PNGCAPI _cdecl
214# endif
215# if PNG_API_RULE == 1 && !defined(PNGAPI)
216# define PNGAPI _stdcall
217# endif
218# endif /* compiler/api */
219
220 /* NOTE: PNGCBAPI always defaults to PNGCAPI. */
221
222# if defined(PNGAPI) && !defined(PNG_USER_PRIVATEBUILD)
223# error "PNG_USER_PRIVATEBUILD must be defined if PNGAPI is changed"
224# endif
225
226# if (defined(_MSC_VER) && _MSC_VER < 800) ||\
227 (defined(__BORLANDC__) && __BORLANDC__ < 0x500)
228 /* older Borland and MSC
229 * compilers used '__export' and required this to be after
230 * the type.
231 */
232# ifndef PNG_EXPORT_TYPE
233# define PNG_EXPORT_TYPE(type) type PNG_IMPEXP
234# endif
235# define PNG_DLL_EXPORT __export
236# else /* newer compiler */
237# define PNG_DLL_EXPORT __declspec(dllexport)
238# ifndef PNG_DLL_IMPORT
239# define PNG_DLL_IMPORT __declspec(dllimport)
240# endif
241# endif /* compiler */
242
243#else /* !Windows */
244# if (defined(__IBMC__) || defined(__IBMCPP__)) && defined(__OS2__)
245# define PNGAPI _System
246# else /* !Windows/x86 && !OS/2 */
247 /* Use the defaults, or define PNG*API on the command line (but
248 * this will have to be done for every compile!)
249 */
250# endif /* other system, !OS/2 */
251#endif /* !Windows/x86 */
252
253/* Now do all the defaulting . */
254#ifndef PNGCAPI
255# define PNGCAPI
256#endif
257#ifndef PNGCBAPI
258# define PNGCBAPI PNGCAPI
259#endif
260#ifndef PNGAPI
261# define PNGAPI PNGCAPI
262#endif
263
264/* PNG_IMPEXP may be set on the compilation system command line or (if not set)
265 * then in an internal header file when building the library, otherwise (when
266 * using the library) it is set here.
267 */
268#ifndef PNG_IMPEXP
269# if defined(PNG_USE_DLL) && defined(PNG_DLL_IMPORT)
270 /* This forces use of a DLL, disallowing static linking */
271# define PNG_IMPEXP PNG_DLL_IMPORT
272# endif
273
274# ifndef PNG_IMPEXP
275# define PNG_IMPEXP
276# endif
277#endif
278
279/* In 1.5.2 the definition of PNG_FUNCTION has been changed to always treat
280 * 'attributes' as a storage class - the attributes go at the start of the
281 * function definition, and attributes are always appended regardless of the
282 * compiler. This considerably simplifies these macros but may cause problems
283 * if any compilers both need function attributes and fail to handle them as
284 * a storage class (this is unlikely.)
285 */
286#ifndef PNG_FUNCTION
287# define PNG_FUNCTION(type, name, args, attributes) attributes type name args
288#endif
289
290#ifndef PNG_EXPORT_TYPE
291# define PNG_EXPORT_TYPE(type) PNG_IMPEXP type
292#endif
293
294 /* The ordinal value is only relevant when preprocessing png.h for symbol
295 * table entries, so we discard it here. See the .dfn files in the
296 * scripts directory.
297 */
298
299#ifndef PNG_EXPORTA
300# define PNG_EXPORTA(ordinal, type, name, args, attributes) \
301 PNG_FUNCTION(PNG_EXPORT_TYPE(type), (PNGAPI name), PNGARG(args), \
302 PNG_LINKAGE_API attributes)
303#endif
304
305/* ANSI-C (C90) does not permit a macro to be invoked with an empty argument,
306 * so make something non-empty to satisfy the requirement:
307 */
308#define PNG_EMPTY /*empty list*/
309
310#define PNG_EXPORT(ordinal, type, name, args) \
311 PNG_EXPORTA(ordinal, type, name, args, PNG_EMPTY)
312
313/* Use PNG_REMOVED to comment out a removed interface. */
314#ifndef PNG_REMOVED
315# define PNG_REMOVED(ordinal, type, name, args, attributes)
316#endif
317
318#ifndef PNG_CALLBACK
319# define PNG_CALLBACK(type, name, args) type (PNGCBAPI name) PNGARG(args)
320#endif
321
322/* Support for compiler specific function attributes. These are used
323 * so that where compiler support is available incorrect use of API
324 * functions in png.h will generate compiler warnings.
325 *
326 * Added at libpng-1.2.41.
327 */
328
329#ifndef PNG_NO_PEDANTIC_WARNINGS
330# ifndef PNG_PEDANTIC_WARNINGS_SUPPORTED
331# define PNG_PEDANTIC_WARNINGS_SUPPORTED
332# endif
333#endif
334
335#ifdef PNG_PEDANTIC_WARNINGS_SUPPORTED
336 /* Support for compiler specific function attributes. These are used
337 * so that where compiler support is available, incorrect use of API
338 * functions in png.h will generate compiler warnings. Added at libpng
339 * version 1.2.41. Disabling these removes the warnings but may also produce
340 * less efficient code.
341 */
342# if defined(__clang__) && defined(__has_attribute)
343 /* Clang defines both __clang__ and __GNUC__. Check __clang__ first. */
344# if !defined(PNG_USE_RESULT) && __has_attribute(__warn_unused_result__)
345# define PNG_USE_RESULT __attribute__((__warn_unused_result__))
346# endif
347# if !defined(PNG_NORETURN) && __has_attribute(__noreturn__)
348# define PNG_NORETURN __attribute__((__noreturn__))
349# endif
350# if !defined(PNG_ALLOCATED) && __has_attribute(__malloc__)
351# define PNG_ALLOCATED __attribute__((__malloc__))
352# endif
353# if !defined(PNG_DEPRECATED) && __has_attribute(__deprecated__)
354# define PNG_DEPRECATED __attribute__((__deprecated__))
355# endif
356# if !defined(PNG_PRIVATE)
357# ifdef __has_extension
358# if __has_extension(attribute_unavailable_with_message)
359# define PNG_PRIVATE __attribute__((__unavailable__(\
360 "This function is not exported by libpng.")))
361# endif
362# endif
363# endif
364# ifndef PNG_RESTRICT
365# define PNG_RESTRICT __restrict
366# endif
367
368# elif defined(__GNUC__)
369# ifndef PNG_USE_RESULT
370# define PNG_USE_RESULT __attribute__((__warn_unused_result__))
371# endif
372# ifndef PNG_NORETURN
373# define PNG_NORETURN __attribute__((__noreturn__))
374# endif
375# if __GNUC__ >= 3
376# ifndef PNG_ALLOCATED
377# define PNG_ALLOCATED __attribute__((__malloc__))
378# endif
379# ifndef PNG_DEPRECATED
380# define PNG_DEPRECATED __attribute__((__deprecated__))
381# endif
382# ifndef PNG_PRIVATE
383# if 0 /* Doesn't work so we use deprecated instead*/
384# define PNG_PRIVATE \
385 __attribute__((warning("This function is not exported by libpng.")))
386# else
387# define PNG_PRIVATE \
388 __attribute__((__deprecated__))
389# endif
390# endif
391# if ((__GNUC__ > 3) || !defined(__GNUC_MINOR__) || (__GNUC_MINOR__ >= 1))
392# ifndef PNG_RESTRICT
393# define PNG_RESTRICT __restrict
394# endif
395# endif /* __GNUC__.__GNUC_MINOR__ > 3.0 */
396# endif /* __GNUC__ >= 3 */
397
398# elif defined(_MSC_VER) && (_MSC_VER >= 1300)
399# ifndef PNG_USE_RESULT
400# define PNG_USE_RESULT /* not supported */
401# endif
402# ifndef PNG_NORETURN
403# define PNG_NORETURN __declspec(noreturn)
404# endif
405# ifndef PNG_ALLOCATED
406# if (_MSC_VER >= 1400)
407# define PNG_ALLOCATED __declspec(restrict)
408# endif
409# endif
410# ifndef PNG_DEPRECATED
411# define PNG_DEPRECATED __declspec(deprecated)
412# endif
413# ifndef PNG_PRIVATE
414# define PNG_PRIVATE __declspec(deprecated)
415# endif
416# ifndef PNG_RESTRICT
417# if (_MSC_VER >= 1400)
418# define PNG_RESTRICT __restrict
419# endif
420# endif
421
422# elif defined(__WATCOMC__)
423# ifndef PNG_RESTRICT
424# define PNG_RESTRICT __restrict
425# endif
426# endif
427#endif /* PNG_PEDANTIC_WARNINGS */
428
429#ifndef PNG_DEPRECATED
430# define PNG_DEPRECATED /* Use of this function is deprecated */
431#endif
432#ifndef PNG_USE_RESULT
433# define PNG_USE_RESULT /* The result of this function must be checked */
434#endif
435#ifndef PNG_NORETURN
436# define PNG_NORETURN /* This function does not return */
437#endif
438#ifndef PNG_ALLOCATED
439# define PNG_ALLOCATED /* The result of the function is new memory */
440#endif
441#ifndef PNG_PRIVATE
442# define PNG_PRIVATE /* This is a private libpng function */
443#endif
444#ifndef PNG_RESTRICT
445# define PNG_RESTRICT /* The C99 "restrict" feature */
446#endif
447
448#ifndef PNG_FP_EXPORT /* A floating point API. */
449# ifdef PNG_FLOATING_POINT_SUPPORTED
450# define PNG_FP_EXPORT(ordinal, type, name, args)\
451 PNG_EXPORT(ordinal, type, name, args);
452# else /* No floating point APIs */
453# define PNG_FP_EXPORT(ordinal, type, name, args)
454# endif
455#endif
456#ifndef PNG_FIXED_EXPORT /* A fixed point API. */
457# ifdef PNG_FIXED_POINT_SUPPORTED
458# define PNG_FIXED_EXPORT(ordinal, type, name, args)\
459 PNG_EXPORT(ordinal, type, name, args);
460# else /* No fixed point APIs */
461# define PNG_FIXED_EXPORT(ordinal, type, name, args)
462# endif
463#endif
464
465#ifndef PNG_BUILDING_SYMBOL_TABLE
466/* Some typedefs to get us started. These should be safe on most of the common
467 * platforms.
468 *
469 * png_uint_32 and png_int_32 may, currently, be larger than required to hold a
470 * 32-bit value however this is not normally advisable.
471 *
472 * png_uint_16 and png_int_16 should always be two bytes in size - this is
473 * verified at library build time.
474 *
475 * png_byte must always be one byte in size.
476 *
477 * The checks below use constants from limits.h, as defined by the ISOC90
478 * standard.
479 */
480#if CHAR_BIT == 8 && UCHAR_MAX == 255
481 typedef unsigned char png_byte;
482#else
483# error "libpng requires 8-bit bytes"
484#endif
485
486#if INT_MIN == -32768 && INT_MAX == 32767
487 typedef int png_int_16;
488#elif SHRT_MIN == -32768 && SHRT_MAX == 32767
489 typedef short png_int_16;
490#else
491# error "libpng requires a signed 16-bit type"
492#endif
493
494#if UINT_MAX == 65535
495 typedef unsigned int png_uint_16;
496#elif USHRT_MAX == 65535
497 typedef unsigned short png_uint_16;
498#else
499# error "libpng requires an unsigned 16-bit type"
500#endif
501
502#if INT_MIN < -2147483646 && INT_MAX > 2147483646
503 typedef int png_int_32;
504#elif LONG_MIN < -2147483646 && LONG_MAX > 2147483646
505 typedef long int png_int_32;
506#else
507# error "libpng requires a signed 32-bit (or more) type"
508#endif
509
510#if UINT_MAX > 4294967294U
511 typedef unsigned int png_uint_32;
512#elif ULONG_MAX > 4294967294U
513 typedef unsigned long int png_uint_32;
514#else
515# error "libpng requires an unsigned 32-bit (or more) type"
516#endif
517
518/* Prior to 1.6.0, it was possible to disable the use of size_t and ptrdiff_t.
519 * From 1.6.0 onwards, an ISO C90 compiler, as well as a standard-compliant
520 * behavior of sizeof and ptrdiff_t are required.
521 * The legacy typedefs are provided here for backwards compatibility.
522 */
523typedef size_t png_size_t;
524typedef ptrdiff_t png_ptrdiff_t;
525
526/* libpng needs to know the maximum value of 'size_t' and this controls the
527 * definition of png_alloc_size_t, below. This maximum value of size_t limits
528 * but does not control the maximum allocations the library makes - there is
529 * direct application control of this through png_set_user_limits().
530 */
531#ifndef PNG_SMALL_SIZE_T
532 /* Compiler specific tests for systems where size_t is known to be less than
533 * 32 bits (some of these systems may no longer work because of the lack of
534 * 'far' support; see above.)
535 */
536# if (defined(__TURBOC__) && !defined(__FLAT__)) ||\
537 (defined(_MSC_VER) && defined(MAXSEG_64K))
538# define PNG_SMALL_SIZE_T
539# endif
540#endif
541
542/* png_alloc_size_t is guaranteed to be no smaller than size_t, and no smaller
543 * than png_uint_32. Casts from size_t or png_uint_32 to png_alloc_size_t are
544 * not necessary; in fact, it is recommended not to use them at all, so that
545 * the compiler can complain when something turns out to be problematic.
546 *
547 * Casts in the other direction (from png_alloc_size_t to size_t or
548 * png_uint_32) should be explicitly applied; however, we do not expect to
549 * encounter practical situations that require such conversions.
550 *
551 * PNG_SMALL_SIZE_T must be defined if the maximum value of size_t is less than
552 * 4294967295 - i.e. less than the maximum value of png_uint_32.
553 */
554#ifdef PNG_SMALL_SIZE_T
555 typedef png_uint_32 png_alloc_size_t;
556#else
557 typedef size_t png_alloc_size_t;
558#endif
559
560/* Prior to 1.6.0 libpng offered limited support for Microsoft C compiler
561 * implementations of Intel CPU specific support of user-mode segmented address
562 * spaces, where 16-bit pointers address more than 65536 bytes of memory using
563 * separate 'segment' registers. The implementation requires two different
564 * types of pointer (only one of which includes the segment value.)
565 *
566 * If required this support is available in version 1.2 of libpng and may be
567 * available in versions through 1.5, although the correctness of the code has
568 * not been verified recently.
569 */
570
571/* Typedef for floating-point numbers that are converted to fixed-point with a
572 * multiple of 100,000, e.g., gamma
573 */
574typedef png_int_32 png_fixed_point;
575
576/* Add typedefs for pointers */
577typedef void * png_voidp;
578typedef const void * png_const_voidp;
579typedef png_byte * png_bytep;
580typedef const png_byte * png_const_bytep;
581typedef png_uint_32 * png_uint_32p;
582typedef const png_uint_32 * png_const_uint_32p;
583typedef png_int_32 * png_int_32p;
584typedef const png_int_32 * png_const_int_32p;
585typedef png_uint_16 * png_uint_16p;
586typedef const png_uint_16 * png_const_uint_16p;
587typedef png_int_16 * png_int_16p;
588typedef const png_int_16 * png_const_int_16p;
589typedef char * png_charp;
590typedef const char * png_const_charp;
591typedef png_fixed_point * png_fixed_point_p;
592typedef const png_fixed_point * png_const_fixed_point_p;
593typedef size_t * png_size_tp;
594typedef const size_t * png_const_size_tp;
595
596#ifdef PNG_STDIO_SUPPORTED
597typedef FILE * png_FILE_p;
598#endif
599
600#ifdef PNG_FLOATING_POINT_SUPPORTED
601typedef double * png_doublep;
602typedef const double * png_const_doublep;
603#endif
604
605/* Pointers to pointers; i.e. arrays */
606typedef png_byte * * png_bytepp;
607typedef png_uint_32 * * png_uint_32pp;
608typedef png_int_32 * * png_int_32pp;
609typedef png_uint_16 * * png_uint_16pp;
610typedef png_int_16 * * png_int_16pp;
611typedef const char * * png_const_charpp;
612typedef char * * png_charpp;
613typedef png_fixed_point * * png_fixed_point_pp;
614#ifdef PNG_FLOATING_POINT_SUPPORTED
615typedef double * * png_doublepp;
616#endif
617
618/* Pointers to pointers to pointers; i.e., pointer to array */
619typedef char * * * png_charppp;
620
621#endif /* PNG_BUILDING_SYMBOL_TABLE */
622
623#endif /* PNGCONF_H */
624

source code of include/libpng16/pngconf.h