c: Implement C23 nullptr (N3042)
[official-gcc.git] / gcc / ginclude / stddef.h
blob315ff7866941c77e2b6d073b634c6ec2d794840f
1 /* Copyright (C) 1989-2022 Free Software Foundation, Inc.
3 This file is part of GCC.
5 GCC is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3, or (at your option)
8 any later version.
10 GCC is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 Under Section 7 of GPL version 3, you are granted additional
16 permissions described in the GCC Runtime Library Exception, version
17 3.1, as published by the Free Software Foundation.
19 You should have received a copy of the GNU General Public License and
20 a copy of the GCC Runtime Library Exception along with this program;
21 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
22 <http://www.gnu.org/licenses/>. */
25 * ISO C Standard: 7.17 Common definitions <stddef.h>
27 #if (!defined(_STDDEF_H) && !defined(_STDDEF_H_) && !defined(_ANSI_STDDEF_H) \
28 && !defined(__STDDEF_H__)) \
29 || defined(__need_wchar_t) || defined(__need_size_t) \
30 || defined(__need_ptrdiff_t) || defined(__need_NULL) \
31 || defined(__need_wint_t)
33 /* Any one of these symbols __need_* means that GNU libc
34 wants us just to define one data type. So don't define
35 the symbols that indicate this file's entire job has been done. */
36 #if (!defined(__need_wchar_t) && !defined(__need_size_t) \
37 && !defined(__need_ptrdiff_t) && !defined(__need_NULL) \
38 && !defined(__need_wint_t))
39 #define _STDDEF_H
40 #define _STDDEF_H_
41 /* snaroff@next.com says the NeXT needs this. */
42 #define _ANSI_STDDEF_H
43 #endif
45 #ifndef __sys_stdtypes_h
46 /* This avoids lossage on SunOS but only if stdtypes.h comes first.
47 There's no way to win with the other order! Sun lossage. */
49 #if defined(__NetBSD__)
50 #include <machine/ansi.h>
51 #endif
53 #if defined (__FreeBSD__)
54 #include <sys/_types.h>
55 #endif
57 #if defined(__NetBSD__)
58 #if !defined(_SIZE_T_) && !defined(_BSD_SIZE_T_)
59 #define _SIZE_T
60 #endif
61 #if !defined(_PTRDIFF_T_) && !defined(_BSD_PTRDIFF_T_)
62 #define _PTRDIFF_T
63 #endif
64 /* On BSD/386 1.1, at least, machine/ansi.h defines _BSD_WCHAR_T_
65 instead of _WCHAR_T_. */
66 #if !defined(_WCHAR_T_) && !defined(_BSD_WCHAR_T_)
67 #ifndef _BSD_WCHAR_T_
68 #define _WCHAR_T
69 #endif
70 #endif
71 /* Undef _FOO_T_ if we are supposed to define foo_t. */
72 #if defined (__need_ptrdiff_t) || defined (_STDDEF_H_)
73 #undef _PTRDIFF_T_
74 #undef _BSD_PTRDIFF_T_
75 #endif
76 #if defined (__need_size_t) || defined (_STDDEF_H_)
77 #undef _SIZE_T_
78 #undef _BSD_SIZE_T_
79 #endif
80 #if defined (__need_wchar_t) || defined (_STDDEF_H_)
81 #undef _WCHAR_T_
82 #undef _BSD_WCHAR_T_
83 #endif
84 #endif /* defined(__NetBSD__) */
86 /* Sequent's header files use _PTRDIFF_T_ in some conflicting way.
87 Just ignore it. */
88 #if defined (__sequent__) && defined (_PTRDIFF_T_)
89 #undef _PTRDIFF_T_
90 #endif
92 /* On VxWorks, <type/vxTypesBase.h> may have defined macros like
93 _TYPE_size_t which will typedef size_t. fixincludes patched the
94 vxTypesBase.h so that this macro is only defined if _GCC_SIZE_T is
95 not defined, and so that defining this macro defines _GCC_SIZE_T.
96 If we find that the macros are still defined at this point, we must
97 invoke them so that the type is defined as expected. */
98 #if defined (_TYPE_ptrdiff_t) && (defined (__need_ptrdiff_t) || defined (_STDDEF_H_))
99 _TYPE_ptrdiff_t;
100 #undef _TYPE_ptrdiff_t
101 #endif
102 #if defined (_TYPE_size_t) && (defined (__need_size_t) || defined (_STDDEF_H_))
103 _TYPE_size_t;
104 #undef _TYPE_size_t
105 #endif
106 #if defined (_TYPE_wchar_t) && (defined (__need_wchar_t) || defined (_STDDEF_H_))
107 _TYPE_wchar_t;
108 #undef _TYPE_wchar_t
109 #endif
111 /* In case nobody has defined these types, but we aren't running under
112 GCC 2.00, make sure that __PTRDIFF_TYPE__, __SIZE_TYPE__, and
113 __WCHAR_TYPE__ have reasonable values. This can happen if the
114 parts of GCC is compiled by an older compiler, that actually
115 include gstddef.h, such as collect2. */
117 /* Signed type of difference of two pointers. */
119 /* Define this type if we are doing the whole job,
120 or if we want this type in particular. */
121 #if defined (_STDDEF_H) || defined (__need_ptrdiff_t)
122 #ifndef _PTRDIFF_T /* in case <sys/types.h> has defined it. */
123 #ifndef _T_PTRDIFF_
124 #ifndef _T_PTRDIFF
125 #ifndef __PTRDIFF_T
126 #ifndef _PTRDIFF_T_
127 #ifndef _BSD_PTRDIFF_T_
128 #ifndef ___int_ptrdiff_t_h
129 #ifndef _GCC_PTRDIFF_T
130 #ifndef _PTRDIFF_T_DECLARED /* DragonFly */
131 #ifndef __DEFINED_ptrdiff_t /* musl libc */
132 #define _PTRDIFF_T
133 #define _T_PTRDIFF_
134 #define _T_PTRDIFF
135 #define __PTRDIFF_T
136 #define _PTRDIFF_T_
137 #define _BSD_PTRDIFF_T_
138 #define ___int_ptrdiff_t_h
139 #define _GCC_PTRDIFF_T
140 #define _PTRDIFF_T_DECLARED
141 #define __DEFINED_ptrdiff_t
142 #ifndef __PTRDIFF_TYPE__
143 #define __PTRDIFF_TYPE__ long int
144 #endif
145 typedef __PTRDIFF_TYPE__ ptrdiff_t;
146 #endif /* __DEFINED_ptrdiff_t */
147 #endif /* _PTRDIFF_T_DECLARED */
148 #endif /* _GCC_PTRDIFF_T */
149 #endif /* ___int_ptrdiff_t_h */
150 #endif /* _BSD_PTRDIFF_T_ */
151 #endif /* _PTRDIFF_T_ */
152 #endif /* __PTRDIFF_T */
153 #endif /* _T_PTRDIFF */
154 #endif /* _T_PTRDIFF_ */
155 #endif /* _PTRDIFF_T */
157 /* If this symbol has done its job, get rid of it. */
158 #undef __need_ptrdiff_t
160 #endif /* _STDDEF_H or __need_ptrdiff_t. */
162 /* Unsigned type of `sizeof' something. */
164 /* Define this type if we are doing the whole job,
165 or if we want this type in particular. */
166 #if defined (_STDDEF_H) || defined (__need_size_t)
167 #ifndef __size_t__ /* BeOS */
168 #ifndef __SIZE_T__ /* Cray Unicos/Mk */
169 #ifndef _SIZE_T /* in case <sys/types.h> has defined it. */
170 #ifndef _SYS_SIZE_T_H
171 #ifndef _T_SIZE_
172 #ifndef _T_SIZE
173 #ifndef __SIZE_T
174 #ifndef _SIZE_T_
175 #ifndef _BSD_SIZE_T_
176 #ifndef _SIZE_T_DEFINED_
177 #ifndef _SIZE_T_DEFINED
178 #ifndef _BSD_SIZE_T_DEFINED_ /* Darwin */
179 #ifndef _SIZE_T_DECLARED /* FreeBSD 5 */
180 #ifndef __DEFINED_size_t /* musl libc */
181 #ifndef ___int_size_t_h
182 #ifndef _GCC_SIZE_T
183 #ifndef _SIZET_
184 #ifndef __size_t
185 #define __size_t__ /* BeOS */
186 #define __SIZE_T__ /* Cray Unicos/Mk */
187 #define _SIZE_T
188 #define _SYS_SIZE_T_H
189 #define _T_SIZE_
190 #define _T_SIZE
191 #define __SIZE_T
192 #define _SIZE_T_
193 #define _BSD_SIZE_T_
194 #define _SIZE_T_DEFINED_
195 #define _SIZE_T_DEFINED
196 #define _BSD_SIZE_T_DEFINED_ /* Darwin */
197 #define _SIZE_T_DECLARED /* FreeBSD 5 */
198 #define __DEFINED_size_t /* musl libc */
199 #define ___int_size_t_h
200 #define _GCC_SIZE_T
201 #define _SIZET_
202 #if defined (__FreeBSD__) \
203 || defined(__DragonFly__) \
204 || defined(__FreeBSD_kernel__) \
205 || defined(__VMS__)
206 /* __size_t is a typedef, must not trash it. */
207 #else
208 #define __size_t
209 #endif
210 #ifndef __SIZE_TYPE__
211 #define __SIZE_TYPE__ long unsigned int
212 #endif
213 #if !(defined (__GNUG__) && defined (size_t))
214 typedef __SIZE_TYPE__ size_t;
215 #ifdef __BEOS__
216 typedef long ssize_t;
217 #endif /* __BEOS__ */
218 #endif /* !(defined (__GNUG__) && defined (size_t)) */
219 #endif /* __size_t */
220 #endif /* _SIZET_ */
221 #endif /* _GCC_SIZE_T */
222 #endif /* ___int_size_t_h */
223 #endif /* __DEFINED_size_t */
224 #endif /* _SIZE_T_DECLARED */
225 #endif /* _BSD_SIZE_T_DEFINED_ */
226 #endif /* _SIZE_T_DEFINED */
227 #endif /* _SIZE_T_DEFINED_ */
228 #endif /* _BSD_SIZE_T_ */
229 #endif /* _SIZE_T_ */
230 #endif /* __SIZE_T */
231 #endif /* _T_SIZE */
232 #endif /* _T_SIZE_ */
233 #endif /* _SYS_SIZE_T_H */
234 #endif /* _SIZE_T */
235 #endif /* __SIZE_T__ */
236 #endif /* __size_t__ */
237 #undef __need_size_t
238 #endif /* _STDDEF_H or __need_size_t. */
241 /* Wide character type.
242 Locale-writers should change this as necessary to
243 be big enough to hold unique values not between 0 and 127,
244 and not (wchar_t) -1, for each defined multibyte character. */
246 /* Define this type if we are doing the whole job,
247 or if we want this type in particular. */
248 #if defined (_STDDEF_H) || defined (__need_wchar_t)
249 #ifndef __wchar_t__ /* BeOS */
250 #ifndef __WCHAR_T__ /* Cray Unicos/Mk */
251 #ifndef _WCHAR_T
252 #ifndef _T_WCHAR_
253 #ifndef _T_WCHAR
254 #ifndef __WCHAR_T
255 #ifndef _WCHAR_T_
256 #ifndef _BSD_WCHAR_T_
257 #ifndef _BSD_WCHAR_T_DEFINED_ /* Darwin */
258 #ifndef _BSD_RUNE_T_DEFINED_ /* Darwin */
259 #ifndef _WCHAR_T_DECLARED /* FreeBSD 5 */
260 #ifndef __DEFINED_wchar_t /* musl libc */
261 #ifndef _WCHAR_T_DEFINED_
262 #ifndef _WCHAR_T_DEFINED
263 #ifndef _WCHAR_T_H
264 #ifndef ___int_wchar_t_h
265 #ifndef __INT_WCHAR_T_H
266 #ifndef _GCC_WCHAR_T
267 #define __wchar_t__ /* BeOS */
268 #define __WCHAR_T__ /* Cray Unicos/Mk */
269 #define _WCHAR_T
270 #define _T_WCHAR_
271 #define _T_WCHAR
272 #define __WCHAR_T
273 #define _WCHAR_T_
274 #define _BSD_WCHAR_T_
275 #define _WCHAR_T_DEFINED_
276 #define _WCHAR_T_DEFINED
277 #define _WCHAR_T_H
278 #define ___int_wchar_t_h
279 #define __INT_WCHAR_T_H
280 #define _GCC_WCHAR_T
281 #define _WCHAR_T_DECLARED
282 #define __DEFINED_wchar_t
284 /* On BSD/386 1.1, at least, machine/ansi.h defines _BSD_WCHAR_T_
285 instead of _WCHAR_T_, and _BSD_RUNE_T_ (which, unlike the other
286 symbols in the _FOO_T_ family, stays defined even after its
287 corresponding type is defined). If we define wchar_t, then we
288 must undef _WCHAR_T_; for BSD/386 1.1 (and perhaps others), if
289 we undef _WCHAR_T_, then we must also define rune_t, since
290 headers like runetype.h assume that if machine/ansi.h is included,
291 and _BSD_WCHAR_T_ is not defined, then rune_t is available.
292 machine/ansi.h says, "Note that _WCHAR_T_ and _RUNE_T_ must be of
293 the same type." */
294 #ifdef _BSD_WCHAR_T_
295 #undef _BSD_WCHAR_T_
296 #ifdef _BSD_RUNE_T_
297 #if !defined (_ANSI_SOURCE) && !defined (_POSIX_SOURCE)
298 typedef _BSD_RUNE_T_ rune_t;
299 #define _BSD_WCHAR_T_DEFINED_
300 #define _BSD_RUNE_T_DEFINED_ /* Darwin */
301 #if defined (__FreeBSD__) && (__FreeBSD__ < 5)
302 /* Why is this file so hard to maintain properly? In contrast to
303 the comment above regarding BSD/386 1.1, on FreeBSD for as long
304 as the symbol has existed, _BSD_RUNE_T_ must not stay defined or
305 redundant typedefs will occur when stdlib.h is included after this file. */
306 #undef _BSD_RUNE_T_
307 #endif
308 #endif
309 #endif
310 #endif
311 /* FreeBSD 5 can't be handled well using "traditional" logic above
312 since it no longer defines _BSD_RUNE_T_ yet still desires to export
313 rune_t in some cases... */
314 #if defined (__FreeBSD__) && (__FreeBSD__ >= 5)
315 #if !defined (_ANSI_SOURCE) && !defined (_POSIX_SOURCE)
316 #if __BSD_VISIBLE
317 #ifndef _RUNE_T_DECLARED
318 typedef __rune_t rune_t;
319 #define _RUNE_T_DECLARED
320 #endif
321 #endif
322 #endif
323 #endif
325 #ifndef __WCHAR_TYPE__
326 #define __WCHAR_TYPE__ int
327 #endif
328 #ifndef __cplusplus
329 typedef __WCHAR_TYPE__ wchar_t;
330 #endif
331 #endif
332 #endif
333 #endif
334 #endif
335 #endif
336 #endif
337 #endif /* __DEFINED_wchar_t */
338 #endif /* _WCHAR_T_DECLARED */
339 #endif /* _BSD_RUNE_T_DEFINED_ */
340 #endif
341 #endif
342 #endif
343 #endif
344 #endif
345 #endif
346 #endif
347 #endif /* __WCHAR_T__ */
348 #endif /* __wchar_t__ */
349 #undef __need_wchar_t
350 #endif /* _STDDEF_H or __need_wchar_t. */
352 #if defined (__need_wint_t)
353 #ifndef _WINT_T
354 #define _WINT_T
356 #ifndef __WINT_TYPE__
357 #define __WINT_TYPE__ unsigned int
358 #endif
359 typedef __WINT_TYPE__ wint_t;
360 #endif
361 #undef __need_wint_t
362 #endif
364 #if defined(__NetBSD__)
365 /* The references to _GCC_PTRDIFF_T_, _GCC_SIZE_T_, and _GCC_WCHAR_T_
366 are probably typos and should be removed before 2.8 is released. */
367 #ifdef _GCC_PTRDIFF_T_
368 #undef _PTRDIFF_T_
369 #undef _BSD_PTRDIFF_T_
370 #endif
371 #ifdef _GCC_SIZE_T_
372 #undef _SIZE_T_
373 #undef _BSD_SIZE_T_
374 #endif
375 #ifdef _GCC_WCHAR_T_
376 #undef _WCHAR_T_
377 #undef _BSD_WCHAR_T_
378 #endif
379 /* The following ones are the real ones. */
380 #ifdef _GCC_PTRDIFF_T
381 #undef _PTRDIFF_T_
382 #undef _BSD_PTRDIFF_T_
383 #endif
384 #ifdef _GCC_SIZE_T
385 #undef _SIZE_T_
386 #undef _BSD_SIZE_T_
387 #endif
388 #ifdef _GCC_WCHAR_T
389 #undef _WCHAR_T_
390 #undef _BSD_WCHAR_T_
391 #endif
392 #endif /* __NetBSD__ */
394 #endif /* __sys_stdtypes_h */
396 /* A null pointer constant. */
398 #if defined (_STDDEF_H) || defined (__need_NULL)
399 #undef NULL /* in case <stdio.h> has defined it. */
400 #ifdef __GNUG__
401 #define NULL __null
402 #else /* G++ */
403 #ifndef __cplusplus
404 #define NULL ((void *)0)
405 #else /* C++ */
406 #define NULL 0
407 #endif /* C++ */
408 #endif /* G++ */
409 #endif /* NULL not defined and <stddef.h> or need NULL. */
410 #undef __need_NULL
412 #ifdef _STDDEF_H
414 /* Offset of member MEMBER in a struct of type TYPE. */
415 #define offsetof(TYPE, MEMBER) __builtin_offsetof (TYPE, MEMBER)
417 #if (defined (__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) \
418 || (defined(__cplusplus) && __cplusplus >= 201103L)
419 #ifndef _GCC_MAX_ALIGN_T
420 #define _GCC_MAX_ALIGN_T
421 /* Type whose alignment is supported in every context and is at least
422 as great as that of any standard type not using alignment
423 specifiers. */
424 typedef struct {
425 long long __max_align_ll __attribute__((__aligned__(__alignof__(long long))));
426 long double __max_align_ld __attribute__((__aligned__(__alignof__(long double))));
427 /* _Float128 is defined as a basic type, so max_align_t must be
428 sufficiently aligned for it. This code must work in C++, so we
429 use __float128 here; that is only available on some
430 architectures, but only on i386 is extra alignment needed for
431 __float128. */
432 #ifdef __i386__
433 __float128 __max_align_f128 __attribute__((__aligned__(__alignof(__float128))));
434 #endif
435 } max_align_t;
436 #endif
437 #endif /* C11 or C++11. */
439 #if defined(__cplusplus) && __cplusplus >= 201103L
440 #ifndef _GXX_NULLPTR_T
441 #define _GXX_NULLPTR_T
442 typedef decltype(nullptr) nullptr_t;
443 #endif
444 #endif /* C++11. */
446 #if (defined (__STDC_VERSION__) && __STDC_VERSION__ > 201710L)
447 #ifndef _GCC_NULLPTR_T
448 #define _GCC_NULLPTR_T
449 typedef __typeof__(nullptr) nullptr_t;
450 /* ??? This doesn't define __STDC_VERSION_STDDEF_H__ yet. */
451 #endif
452 #endif /* C23. */
454 #endif /* _STDDEF_H was defined this time */
456 #endif /* !_STDDEF_H && !_STDDEF_H_ && !_ANSI_STDDEF_H && !__STDDEF_H__
457 || __need_XXX was not defined before */