1 /* Copyright (C) 1992-2021 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU General Public
6 License as published by the Free Software Foundation; either
7 version 3 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 General Public License for more details.
13
14 You should have received a copy of the GNU General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18 #ifndef _SYS_CDEFS_H
19 #define _SYS_CDEFS_H 1
20
21 /* We are almost always included from features.h. */
22 #ifndef _FEATURES_H
23 # include <features.h>
24 #endif
25
26 /* The GNU libc does not support any K&R compilers or the traditional mode
27 of ISO C compilers anymore. Check for some of the combinations not
28 supported anymore. */
29 #if defined __GNUC__ && !defined __STDC__
30 # error "You need a ISO C conforming compiler to use the glibc headers"
31 #endif
32
33 /* Some user header file might have defined this before. */
34 #undef __P
35 #undef __PMT
36
37 /* Compilers that lack __has_attribute may object to
38 #if defined __has_attribute && __has_attribute (...)
39 even though they do not need to evaluate the right-hand side of the &&.
40 Similarly for __has_builtin, etc. */
41 #if (defined __has_attribute \
42 && (!defined __clang_minor__ \
43 || 3 < __clang_major__ + (5 <= __clang_minor__)))
44 # define __glibc_has_attribute(attr) __has_attribute (attr)
45 #else
46 # define __glibc_has_attribute(attr) 0
47 #endif
48 #ifdef __has_builtin
49 # define __glibc_has_builtin(name) __has_builtin (name)
50 #else
51 # define __glibc_has_builtin(name) 0
52 #endif
53 #ifdef __has_extension
54 # define __glibc_has_extension(ext) __has_extension (ext)
55 #else
56 # define __glibc_has_extension(ext) 0
57 #endif
58
59 #if defined __GNUC__ || defined __clang__
60
61 /* All functions, except those with callbacks or those that
62 synchronize memory, are leaf functions. */
63 # if __GNUC_PREREQ (4, 6) && !defined _LIBC
64 # define __LEAF , __leaf__
65 # define __LEAF_ATTR __attribute__ ((__leaf__))
66 # else
67 # define __LEAF
68 # define __LEAF_ATTR
69 # endif
70
71 /* GCC can always grok prototypes. For C++ programs we add throw()
72 to help it optimize the function calls. But this only works with
73 gcc 2.8.x and egcs. For gcc 3.4 and up we even mark C functions
74 as non-throwing using a function attribute since programs can use
75 the -fexceptions options for C code as well. */
76 # if !defined __cplusplus \
77 && (__GNUC_PREREQ (3, 4) || __glibc_has_attribute (__nothrow__))
78 # define __THROW __attribute__ ((__nothrow__ __LEAF))
79 # define __THROWNL __attribute__ ((__nothrow__))
80 # define __NTH(fct) __attribute__ ((__nothrow__ __LEAF)) fct
81 # define __NTHNL(fct) __attribute__ ((__nothrow__)) fct
82 # else
83 # if defined __cplusplus && (__GNUC_PREREQ (2,8) || __clang_major >= 4)
84 # if __cplusplus >= 201103L
85 # define __THROW noexcept (true)
86 # else
87 # define __THROW throw ()
88 # endif
89 # define __THROWNL __THROW
90 # define __NTH(fct) __LEAF_ATTR fct __THROW
91 # define __NTHNL(fct) fct __THROW
92 # else
93 # define __THROW
94 # define __THROWNL
95 # define __NTH(fct) fct
96 # define __NTHNL(fct) fct
97 # endif
98 # endif
99
100 #else /* Not GCC or clang. */
101
102 # if (defined __cplusplus \
103 || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
104 # define __inline inline
105 # else
106 # define __inline /* No inline functions. */
107 # endif
108
109 # define __THROW
110 # define __THROWNL
111 # define __NTH(fct) fct
112
113 #endif /* GCC || clang. */
114
115 /* These two macros are not used in glibc anymore. They are kept here
116 only because some other projects expect the macros to be defined. */
117 #define __P(args) args
118 #define __PMT(args) args
119
120 /* For these things, GCC behaves the ANSI way normally,
121 and the non-ANSI way under -traditional. */
122
123 #define __CONCAT(x,y) x ## y
124 #define __STRING(x) #x
125
126 /* This is not a typedef so `const __ptr_t' does the right thing. */
127 #define __ptr_t void *
128
129
130 /* C++ needs to know that types and declarations are C, not C++. */
131 #ifdef __cplusplus
132 # define __BEGIN_DECLS extern "C" {
133 # define __END_DECLS }
134 #else
135 # define __BEGIN_DECLS
136 # define __END_DECLS
137 #endif
138
139
140 /* Fortify support. */
141 #define __bos(ptr) __builtin_object_size (ptr, __USE_FORTIFY_LEVEL > 1)
142 #define __bos0(ptr) __builtin_object_size (ptr, 0)
143
144 /* Use __builtin_dynamic_object_size at _FORTIFY_SOURCE=3 when available. */
145 #if __USE_FORTIFY_LEVEL == 3 && __glibc_clang_prereq (9, 0)
146 # define __glibc_objsize0(__o) __builtin_dynamic_object_size (__o, 0)
147 # define __glibc_objsize(__o) __builtin_dynamic_object_size (__o, 1)
148 #else
149 # define __glibc_objsize0(__o) __bos0 (__o)
150 # define __glibc_objsize(__o) __bos (__o)
151 #endif
152
153 #if __GNUC_PREREQ (4,3)
154 # define __warnattr(msg) __attribute__((__warning__ (msg)))
155 # define __errordecl(name, msg) \
156 extern void name (void) __attribute__((__error__ (msg)))
157 #else
158 # define __warnattr(msg)
159 # define __errordecl(name, msg) extern void name (void)
160 #endif
161
162 /* Support for flexible arrays.
163 Headers that should use flexible arrays only if they're "real"
164 (e.g. only if they won't affect sizeof()) should test
165 #if __glibc_c99_flexarr_available. */
166 #if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L && !defined __HP_cc
167 # define __flexarr []
168 # define __glibc_c99_flexarr_available 1
169 #elif __GNUC_PREREQ (2,97) || defined __clang__
170 /* GCC 2.97 and clang support C99 flexible array members as an extension,
171 even when in C89 mode or compiling C++ (any version). */
172 # define __flexarr []
173 # define __glibc_c99_flexarr_available 1
174 #elif defined __GNUC__
175 /* Pre-2.97 GCC did not support C99 flexible arrays but did have
176 an equivalent extension with slightly different notation. */
177 # define __flexarr [0]
178 # define __glibc_c99_flexarr_available 1
179 #else
180 /* Some other non-C99 compiler. Approximate with [1]. */
181 # define __flexarr [1]
182 # define __glibc_c99_flexarr_available 0
183 #endif
184
185
186 /* __asm__ ("xyz") is used throughout the headers to rename functions
187 at the assembly language level. This is wrapped by the __REDIRECT
188 macro, in order to support compilers that can do this some other
189 way. When compilers don't support asm-names at all, we have to do
190 preprocessor tricks instead (which don't have exactly the right
191 semantics, but it's the best we can do).
192
193 Example:
194 int __REDIRECT(setpgrp, (__pid_t pid, __pid_t pgrp), setpgid); */
195
196 #if (defined __GNUC__ && __GNUC__ >= 2) || (__clang_major__ >= 4)
197
198 # define __REDIRECT(name, proto, alias) name proto __asm__ (__ASMNAME (#alias))
199 # ifdef __cplusplus
200 # define __REDIRECT_NTH(name, proto, alias) \
201 name proto __THROW __asm__ (__ASMNAME (#alias))
202 # define __REDIRECT_NTHNL(name, proto, alias) \
203 name proto __THROWNL __asm__ (__ASMNAME (#alias))
204 # else
205 # define __REDIRECT_NTH(name, proto, alias) \
206 name proto __asm__ (__ASMNAME (#alias)) __THROW
207 # define __REDIRECT_NTHNL(name, proto, alias) \
208 name proto __asm__ (__ASMNAME (#alias)) __THROWNL
209 # endif
210 # define __ASMNAME(cname) __ASMNAME2 (__USER_LABEL_PREFIX__, cname)
211 # define __ASMNAME2(prefix, cname) __STRING (prefix) cname
212
213 /*
214 #elif __SOME_OTHER_COMPILER__
215
216 # define __REDIRECT(name, proto, alias) name proto; \
217 _Pragma("let " #name " = " #alias)
218 */
219 #endif
220
221 /* GCC and clang have various useful declarations that can be made with
222 the '__attribute__' syntax. All of the ways we use this do fine if
223 they are omitted for compilers that don't understand it. */
224 #if !(defined __GNUC__ || defined __clang__)
225 # define __attribute__(xyz) /* Ignore */
226 #endif
227
228 /* At some point during the gcc 2.96 development the `malloc' attribute
229 for functions was introduced. We don't want to use it unconditionally
230 (although this would be possible) since it generates warnings. */
231 #if __GNUC_PREREQ (2,96) || __glibc_has_attribute (__malloc__)
232 # define __attribute_malloc__ __attribute__ ((__malloc__))
233 #else
234 # define __attribute_malloc__ /* Ignore */
235 #endif
236
237 /* Tell the compiler which arguments to an allocation function
238 indicate the size of the allocation. */
239 #if __GNUC_PREREQ (4, 3)
240 # define __attribute_alloc_size__(params) \
241 __attribute__ ((__alloc_size__ params))
242 #else
243 # define __attribute_alloc_size__(params) /* Ignore. */
244 #endif
245
246 /* At some point during the gcc 2.96 development the `pure' attribute
247 for functions was introduced. We don't want to use it unconditionally
248 (although this would be possible) since it generates warnings. */
249 #if __GNUC_PREREQ (2,96) || __glibc_has_attribute (__pure__)
250 # define __attribute_pure__ __attribute__ ((__pure__))
251 #else
252 # define __attribute_pure__ /* Ignore */
253 #endif
254
255 /* This declaration tells the compiler that the value is constant. */
256 #if __GNUC_PREREQ (2,5) || __glibc_has_attribute (__const__)
257 # define __attribute_const__ __attribute__ ((__const__))
258 #else
259 # define __attribute_const__ /* Ignore */
260 #endif
261
262 #if __GNUC_PREREQ (2,7) || __glibc_has_attribute (__unused__)
263 # define __attribute_maybe_unused__ __attribute__ ((__unused__))
264 /* Once the next version of the C standard comes out, we can
265 do something like the following here:
266 #elif defined __STDC_VERSION__ && 202???L <= __STDC_VERSION__
267 # define __attribute_maybe_unused__ [[__maybe_unused__]] */
268 #else
269 # define __attribute_maybe_unused__ /* Ignore */
270 #endif
271
272 /* At some point during the gcc 3.1 development the `used' attribute
273 for functions was introduced. We don't want to use it unconditionally
274 (although this would be possible) since it generates warnings. */
275 #if __GNUC_PREREQ (3,1) || __glibc_has_attribute (__used__)
276 # define __attribute_used__ __attribute__ ((__used__))
277 # define __attribute_noinline__ __attribute__ ((__noinline__))
278 #else
279 # define __attribute_used__ __attribute__ ((__unused__))
280 # define __attribute_noinline__ /* Ignore */
281 #endif
282
283 /* Since version 3.2, gcc allows marking deprecated functions. */
284 #if __GNUC_PREREQ (3,2) || __glibc_has_attribute (__deprecated__)
285 # define __attribute_deprecated__ __attribute__ ((__deprecated__))
286 #else
287 # define __attribute_deprecated__ /* Ignore */
288 #endif
289
290 /* Since version 4.5, gcc also allows one to specify the message printed
291 when a deprecated function is used. clang claims to be gcc 4.2, but
292 may also support this feature. */
293 #if __GNUC_PREREQ (4,5) \
294 || __glibc_has_extension (__attribute_deprecated_with_message__)
295 # define __attribute_deprecated_msg__(msg) \
296 __attribute__ ((__deprecated__ (msg)))
297 #else
298 # define __attribute_deprecated_msg__(msg) __attribute_deprecated__
299 #endif
300
301 /* At some point during the gcc 2.8 development the `format_arg' attribute
302 for functions was introduced. We don't want to use it unconditionally
303 (although this would be possible) since it generates warnings.
304 If several `format_arg' attributes are given for the same function, in
305 gcc-3.0 and older, all but the last one are ignored. In newer gccs,
306 all designated arguments are considered. */
307 #if __GNUC_PREREQ (2,8) || __glibc_has_attribute (__format_arg__)
308 # define __attribute_format_arg__(x) __attribute__ ((__format_arg__ (x)))
309 #else
310 # define __attribute_format_arg__(x) /* Ignore */
311 #endif
312
313 /* At some point during the gcc 2.97 development the `strfmon' format
314 attribute for functions was introduced. We don't want to use it
315 unconditionally (although this would be possible) since it
316 generates warnings. */
317 #if __GNUC_PREREQ (2,97) || __glibc_has_attribute (__format__)
318 # define __attribute_format_strfmon__(a,b) \
319 __attribute__ ((__format__ (__strfmon__, a, b)))
320 #else
321 # define __attribute_format_strfmon__(a,b) /* Ignore */
322 #endif
323
324 /* The nonnull function attribute marks pointer parameters that
325 must not be NULL. This has the name __nonnull in glibc,
326 and __attribute_nonnull__ in files shared with Gnulib to avoid
327 collision with a different __nonnull in DragonFlyBSD 5.9. */
328 #ifndef __attribute_nonnull__
329 # if __GNUC_PREREQ (3,3) || __glibc_has_attribute (__nonnull__)
330 # define __attribute_nonnull__(params) __attribute__ ((__nonnull__ params))
331 # else
332 # define __attribute_nonnull__(params)
333 # endif
334 #endif
335 #ifndef __nonnull
336 # define __nonnull(params) __attribute_nonnull__ (params)
337 #endif
338
339 /* If fortification mode, we warn about unused results of certain
340 function calls which can lead to problems. */
341 #if __GNUC_PREREQ (3,4) || __glibc_has_attribute (__warn_unused_result__)
342 # define __attribute_warn_unused_result__ \
343 __attribute__ ((__warn_unused_result__))
344 # if defined __USE_FORTIFY_LEVEL && __USE_FORTIFY_LEVEL > 0
345 # define __wur __attribute_warn_unused_result__
346 # endif
347 #else
348 # define __attribute_warn_unused_result__ /* empty */
349 #endif
350 #ifndef __wur
351 # define __wur /* Ignore */
352 #endif
353
354 /* Forces a function to be always inlined. */
355 #if __GNUC_PREREQ (3,2) || __glibc_has_attribute (__always_inline__)
356 /* The Linux kernel defines __always_inline in stddef.h (283d7573), and
357 it conflicts with this definition. Therefore undefine it first to
358 allow either header to be included first. */
359 # undef __always_inline
360 # define __always_inline __inline __attribute__ ((__always_inline__))
361 #else
362 # undef __always_inline
363 # define __always_inline __inline
364 #endif
365
366 /* Associate error messages with the source location of the call site rather
367 than with the source location inside the function. */
368 #if __GNUC_PREREQ (4,3) || __glibc_has_attribute (__artificial__)
369 # define __attribute_artificial__ __attribute__ ((__artificial__))
370 #else
371 # define __attribute_artificial__ /* Ignore */
372 #endif
373
374 /* GCC 4.3 and above with -std=c99 or -std=gnu99 implements ISO C99
375 inline semantics, unless -fgnu89-inline is used. Using __GNUC_STDC_INLINE__
376 or __GNUC_GNU_INLINE is not a good enough check for gcc because gcc versions
377 older than 4.3 may define these macros and still not guarantee GNU inlining
378 semantics.
379
380 clang++ identifies itself as gcc-4.2, but has support for GNU inlining
381 semantics, that can be checked for by using the __GNUC_STDC_INLINE_ and
382 __GNUC_GNU_INLINE__ macro definitions. */
383 #if (!defined __cplusplus || __GNUC_PREREQ (4,3) \
384 || (defined __clang__ && (defined __GNUC_STDC_INLINE__ \
385 || defined __GNUC_GNU_INLINE__)))
386 # if defined __GNUC_STDC_INLINE__ || defined __cplusplus
387 # define __extern_inline extern __inline __attribute__ ((__gnu_inline__))
388 # define __extern_always_inline \
389 extern __always_inline __attribute__ ((__gnu_inline__))
390 # else
391 # define __extern_inline extern __inline
392 # define __extern_always_inline extern __always_inline
393 # endif
394 #endif
395
396 #ifdef __extern_always_inline
397 # define __fortify_function __extern_always_inline __attribute_artificial__
398 #endif
399
400 /* GCC 4.3 and above allow passing all anonymous arguments of an
401 __extern_always_inline function to some other vararg function. */
402 #if __GNUC_PREREQ (4,3)
403 # define __va_arg_pack() __builtin_va_arg_pack ()
404 # define __va_arg_pack_len() __builtin_va_arg_pack_len ()
405 #endif
406
407 /* It is possible to compile containing GCC extensions even if GCC is
408 run in pedantic mode if the uses are carefully marked using the
409 `__extension__' keyword. But this is not generally available before
410 version 2.8. */
411 #if !(__GNUC_PREREQ (2,8) || defined __clang__)
412 # define __extension__ /* Ignore */
413 #endif
414
415 /* __restrict is known in EGCS 1.2 and above, and in clang.
416 It works also in C++ mode (outside of arrays), but only when spelled
417 as '__restrict', not 'restrict'. */
418 #if !(__GNUC_PREREQ (2,92) || __clang_major__ >= 3)
419 # if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
420 # define __restrict restrict
421 # else
422 # define __restrict /* Ignore */
423 # endif
424 #endif
425
426 /* ISO C99 also allows to declare arrays as non-overlapping. The syntax is
427 array_name[restrict]
428 GCC 3.1 and clang support this.
429 This syntax is not usable in C++ mode. */
430 #if (__GNUC_PREREQ (3,1) || __clang_major__ >= 3) && !defined __cplusplus
431 # define __restrict_arr __restrict
432 #else
433 # ifdef __GNUC__
434 # define __restrict_arr /* Not supported in old GCC. */
435 # else
436 # if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
437 # define __restrict_arr restrict
438 # else
439 /* Some other non-C99 compiler. */
440 # define __restrict_arr /* Not supported. */
441 # endif
442 # endif
443 #endif
444
445 #if (__GNUC__ >= 3) || __glibc_has_builtin (__builtin_expect)
446 # define __glibc_unlikely(cond) __builtin_expect ((cond), 0)
447 # define __glibc_likely(cond) __builtin_expect ((cond), 1)
448 #else
449 # define __glibc_unlikely(cond) (cond)
450 # define __glibc_likely(cond) (cond)
451 #endif
452
453 #if (!defined _Noreturn \
454 && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \
455 && !(__GNUC_PREREQ (4,7) \
456 || (3 < __clang_major__ + (5 <= __clang_minor__))))
457 # if __GNUC_PREREQ (2,8)
458 # define _Noreturn __attribute__ ((__noreturn__))
459 # else
460 # define _Noreturn
461 # endif
462 #endif
463
464 #if __GNUC_PREREQ (8, 0)
465 /* Describes a char array whose address can safely be passed as the first
466 argument to strncpy and strncat, as the char array is not necessarily
467 a NUL-terminated string. */
468 # define __attribute_nonstring__ __attribute__ ((__nonstring__))
469 #else
470 # define __attribute_nonstring__
471 #endif
472
473 /* Undefine (also defined in libc-symbols.h). */
474 #undef __attribute_copy__
475 #if __GNUC_PREREQ (9, 0)
476 /* Copies attributes from the declaration or type referenced by
477 the argument. */
478 # define __attribute_copy__(arg) __attribute__ ((__copy__ (arg)))
479 #else
480 # define __attribute_copy__(arg)
481 #endif
482
483 #if (!defined _Static_assert && !defined __cplusplus \
484 && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \
485 && (!(__GNUC_PREREQ (4, 6) || __clang_major__ >= 4) \
486 || defined __STRICT_ANSI__))
487 # define _Static_assert(expr, diagnostic) \
488 extern int (*__Static_assert_function (void)) \
489 [!!sizeof (struct { int __error_if_negative: (expr) ? 2 : -1; })]
490 #endif
491
492 /* Gnulib avoids including these, as they don't work on non-glibc or
493 older glibc platforms. */
494 #ifndef __GNULIB_CDEFS
495 # include <bits/wordsize.h>
496 # include <bits/long-double.h>
497 #endif
498
499 #if __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
500 # ifdef __REDIRECT
501
502 /* Alias name defined automatically. */
503 # define __LDBL_REDIR(name, proto) ... unused__ldbl_redir
504 # define __LDBL_REDIR_DECL(name) \
505 extern __typeof (name) name __asm (__ASMNAME ("__" #name "ieee128"));
506
507 /* Alias name defined automatically, with leading underscores. */
508 # define __LDBL_REDIR2_DECL(name) \
509 extern __typeof (__##name) __##name \
510 __asm (__ASMNAME ("__" #name "ieee128"));
511
512 /* Alias name defined manually. */
513 # define __LDBL_REDIR1(name, proto, alias) ... unused__ldbl_redir1
514 # define __LDBL_REDIR1_DECL(name, alias) \
515 extern __typeof (name) name __asm (__ASMNAME (#alias));
516
517 # define __LDBL_REDIR1_NTH(name, proto, alias) \
518 __REDIRECT_NTH (name, proto, alias)
519 # define __REDIRECT_NTH_LDBL(name, proto, alias) \
520 __LDBL_REDIR1_NTH (name, proto, __##alias##ieee128)
521
522 /* Unused. */
523 # define __REDIRECT_LDBL(name, proto, alias) ... unused__redirect_ldbl
524 # define __LDBL_REDIR_NTH(name, proto) ... unused__ldbl_redir_nth
525
526 # else
527 _Static_assert (0, "IEEE 128-bits long double requires redirection on this platform");
528 # endif
529 #elif defined __LONG_DOUBLE_MATH_OPTIONAL && defined __NO_LONG_DOUBLE_MATH
530 # define __LDBL_COMPAT 1
531 # ifdef __REDIRECT
532 # define __LDBL_REDIR1(name, proto, alias) __REDIRECT (name, proto, alias)
533 # define __LDBL_REDIR(name, proto) \
534 __LDBL_REDIR1 (name, proto, __nldbl_##name)
535 # define __LDBL_REDIR1_NTH(name, proto, alias) __REDIRECT_NTH (name, proto, alias)
536 # define __LDBL_REDIR_NTH(name, proto) \
537 __LDBL_REDIR1_NTH (name, proto, __nldbl_##name)
538 # define __LDBL_REDIR2_DECL(name) \
539 extern __typeof (__##name) __##name __asm (__ASMNAME ("__nldbl___" #name));
540 # define __LDBL_REDIR1_DECL(name, alias) \
541 extern __typeof (name) name __asm (__ASMNAME (#alias));
542 # define __LDBL_REDIR_DECL(name) \
543 extern __typeof (name) name __asm (__ASMNAME ("__nldbl_" #name));
544 # define __REDIRECT_LDBL(name, proto, alias) \
545 __LDBL_REDIR1 (name, proto, __nldbl_##alias)
546 # define __REDIRECT_NTH_LDBL(name, proto, alias) \
547 __LDBL_REDIR1_NTH (name, proto, __nldbl_##alias)
548 # endif
549 #endif
550 #if (!defined __LDBL_COMPAT && __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 0) \
551 || !defined __REDIRECT
552 # define __LDBL_REDIR1(name, proto, alias) name proto
553 # define __LDBL_REDIR(name, proto) name proto
554 # define __LDBL_REDIR1_NTH(name, proto, alias) name proto __THROW
555 # define __LDBL_REDIR_NTH(name, proto) name proto __THROW
556 # define __LDBL_REDIR2_DECL(name)
557 # define __LDBL_REDIR_DECL(name)
558 # ifdef __REDIRECT
559 # define __REDIRECT_LDBL(name, proto, alias) __REDIRECT (name, proto, alias)
560 # define __REDIRECT_NTH_LDBL(name, proto, alias) \
561 __REDIRECT_NTH (name, proto, alias)
562 # endif
563 #endif
564
565 /* __glibc_macro_warning (MESSAGE) issues warning MESSAGE. This is
566 intended for use in preprocessor macros.
567
568 Note: MESSAGE must be a _single_ string; concatenation of string
569 literals is not supported. */
570 #if __GNUC_PREREQ (4,8) || __glibc_clang_prereq (3,5)
571 # define __glibc_macro_warning1(message) _Pragma (#message)
572 # define __glibc_macro_warning(message) \
573 __glibc_macro_warning1 (GCC warning message)
574 #else
575 # define __glibc_macro_warning(msg)
576 #endif
577
578 /* Generic selection (ISO C11) is a C-only feature, available in GCC
579 since version 4.9. Previous versions do not provide generic
580 selection, even though they might set __STDC_VERSION__ to 201112L,
581 when in -std=c11 mode. Thus, we must check for !defined __GNUC__
582 when testing __STDC_VERSION__ for generic selection support.
583 On the other hand, Clang also defines __GNUC__, so a clang-specific
584 check is required to enable the use of generic selection. */
585 #if !defined __cplusplus \
586 && (__GNUC_PREREQ (4, 9) \
587 || __glibc_has_extension (c_generic_selections) \
588 || (!defined __GNUC__ && defined __STDC_VERSION__ \
589 && __STDC_VERSION__ >= 201112L))
590 # define __HAVE_GENERIC_SELECTION 1
591 #else
592 # define __HAVE_GENERIC_SELECTION 0
593 #endif
594
595 #if __GNUC_PREREQ (10, 0)
596 /* Designates a 1-based positional argument ref-index of pointer type
597 that can be used to access size-index elements of the pointed-to
598 array according to access mode, or at least one element when
599 size-index is not provided:
600 access (access-mode, <ref-index> [, <size-index>]) */
601 #define __attr_access(x) __attribute__ ((__access__ x))
602 #else
603 # define __attr_access(x)
604 #endif
605
606 /* Specify that a function such as setjmp or vfork may return
607 twice. */
608 #if __GNUC_PREREQ (4, 1)
609 # define __attribute_returns_twice__ __attribute__ ((__returns_twice__))
610 #else
611 # define __attribute_returns_twice__ /* Ignore. */
612 #endif
613
614 #endif /* sys/cdefs.h */