1 /* Copyright (C) 1992-2021 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
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.
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.
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/>. */
19 #define _SYS_CDEFS_H 1
21 /* We are almost always included from features.h. */
23 # include <features.h>
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
29 #if defined __GNUC__ && !defined __STDC__
30 # error "You need a ISO C conforming compiler to use the glibc headers"
33 /* Some user header file might have defined this before. */
37 /* Compilers that are not clang may object to
38 #if defined __clang__ && __has_attribute(...)
39 even though they do not need to evaluate the right-hand side of the &&. */
40 #if defined __clang__ && defined __has_attribute
41 # define __glibc_clang_has_attribute(name) __has_attribute (name)
43 # define __glibc_clang_has_attribute(name) 0
46 /* Compilers that are not clang may object to
47 #if defined __clang__ && __has_builtin(...)
48 even though they do not need to evaluate the right-hand side of the &&. */
49 #if defined __clang__ && defined __has_builtin
50 # define __glibc_clang_has_builtin(name) __has_builtin (name)
52 # define __glibc_clang_has_builtin(name) 0
55 /* Compilers that are not clang may object to
56 #if defined __clang__ && __has_extension(...)
57 even though they do not need to evaluate the right-hand side of the &&. */
58 #if defined __clang__ && defined __has_extension
59 # define __glibc_clang_has_extension(ext) __has_extension (ext)
61 # define __glibc_clang_has_extension(ext) 0
64 #if defined __GNUC__ || defined __clang__
66 /* All functions, except those with callbacks or those that
67 synchronize memory, are leaf functions. */
68 # if __GNUC_PREREQ (4, 6) && !defined _LIBC
69 # define __LEAF , __leaf__
70 # define __LEAF_ATTR __attribute__ ((__leaf__))
76 /* GCC can always grok prototypes. For C++ programs we add throw()
77 to help it optimize the function calls. But this only works with
78 gcc 2.8.x and egcs. For gcc 3.4 and up we even mark C functions
79 as non-throwing using a function attribute since programs can use
80 the -fexceptions options for C code as well. */
81 # if !defined __cplusplus \
82 && (__GNUC_PREREQ (3, 4) || __glibc_clang_has_attribute (__nothrow__))
83 # define __THROW __attribute__ ((__nothrow__ __LEAF))
84 # define __THROWNL __attribute__ ((__nothrow__))
85 # define __NTH(fct) __attribute__ ((__nothrow__ __LEAF)) fct
86 # define __NTHNL(fct) __attribute__ ((__nothrow__)) fct
88 # if defined __cplusplus && (__GNUC_PREREQ (2,8) || __clang_major >= 4)
89 # if __cplusplus >= 201103L
90 # define __THROW noexcept (true)
92 # define __THROW throw ()
94 # define __THROWNL __THROW
95 # define __NTH(fct) __LEAF_ATTR fct __THROW
96 # define __NTHNL(fct) fct __THROW
100 # define __NTH(fct) fct
101 # define __NTHNL(fct) fct
105 #else /* Not GCC or clang. */
107 # if (defined __cplusplus \
108 || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
109 # define __inline inline
111 # define __inline /* No inline functions. */
116 # define __NTH(fct) fct
118 #endif /* GCC || clang. */
120 /* These two macros are not used in glibc anymore. They are kept here
121 only because some other projects expect the macros to be defined. */
122 #define __P(args) args
123 #define __PMT(args) args
125 /* For these things, GCC behaves the ANSI way normally,
126 and the non-ANSI way under -traditional. */
128 #define __CONCAT(x,y) x ## y
129 #define __STRING(x) #x
131 /* This is not a typedef so `const __ptr_t' does the right thing. */
132 #define __ptr_t void *
135 /* C++ needs to know that types and declarations are C, not C++. */
137 # define __BEGIN_DECLS extern "C" {
138 # define __END_DECLS }
140 # define __BEGIN_DECLS
145 /* Fortify support. */
146 #define __bos(ptr) __builtin_object_size (ptr, __USE_FORTIFY_LEVEL > 1)
147 #define __bos0(ptr) __builtin_object_size (ptr, 0)
149 /* Use __builtin_dynamic_object_size at _FORTIFY_SOURCE=3 when available. */
150 #if __USE_FORTIFY_LEVEL == 3 && __glibc_clang_prereq (9, 0)
151 # define __glibc_objsize0(__o) __builtin_dynamic_object_size (__o, 0)
152 # define __glibc_objsize(__o) __builtin_dynamic_object_size (__o, 1)
154 # define __glibc_objsize0(__o) __bos0 (__o)
155 # define __glibc_objsize(__o) __bos (__o)
158 #if __GNUC_PREREQ (4,3)
159 # define __warnattr(msg) __attribute__((__warning__ (msg)))
160 # define __errordecl(name, msg) \
161 extern void name (void) __attribute__((__error__ (msg)))
163 # define __warnattr(msg)
164 # define __errordecl(name, msg) extern void name (void)
167 /* Support for flexible arrays.
168 Headers that should use flexible arrays only if they're "real"
169 (e.g. only if they won't affect sizeof()) should test
170 #if __glibc_c99_flexarr_available. */
171 #if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L && !defined __HP_cc
172 # define __flexarr []
173 # define __glibc_c99_flexarr_available 1
174 #elif __GNUC_PREREQ (2,97) || defined __clang__
175 /* GCC 2.97 and clang support C99 flexible array members as an extension,
176 even when in C89 mode or compiling C++ (any version). */
177 # define __flexarr []
178 # define __glibc_c99_flexarr_available 1
179 #elif defined __GNUC__
180 /* Pre-2.97 GCC did not support C99 flexible arrays but did have
181 an equivalent extension with slightly different notation. */
182 # define __flexarr [0]
183 # define __glibc_c99_flexarr_available 1
185 /* Some other non-C99 compiler. Approximate with [1]. */
186 # define __flexarr [1]
187 # define __glibc_c99_flexarr_available 0
191 /* __asm__ ("xyz") is used throughout the headers to rename functions
192 at the assembly language level. This is wrapped by the __REDIRECT
193 macro, in order to support compilers that can do this some other
194 way. When compilers don't support asm-names at all, we have to do
195 preprocessor tricks instead (which don't have exactly the right
196 semantics, but it's the best we can do).
199 int __REDIRECT(setpgrp, (__pid_t pid, __pid_t pgrp), setpgid); */
201 #if (defined __GNUC__ && __GNUC__ >= 2) || (__clang_major__ >= 4)
203 # define __REDIRECT(name, proto, alias) name proto __asm__ (__ASMNAME (#alias))
205 # define __REDIRECT_NTH(name, proto, alias) \
206 name proto __THROW __asm__ (__ASMNAME (#alias))
207 # define __REDIRECT_NTHNL(name, proto, alias) \
208 name proto __THROWNL __asm__ (__ASMNAME (#alias))
210 # define __REDIRECT_NTH(name, proto, alias) \
211 name proto __asm__ (__ASMNAME (#alias)) __THROW
212 # define __REDIRECT_NTHNL(name, proto, alias) \
213 name proto __asm__ (__ASMNAME (#alias)) __THROWNL
215 # define __ASMNAME(cname) __ASMNAME2 (__USER_LABEL_PREFIX__, cname)
216 # define __ASMNAME2(prefix, cname) __STRING (prefix) cname
219 #elif __SOME_OTHER_COMPILER__
221 # define __REDIRECT(name, proto, alias) name proto; \
222 _Pragma("let " #name " = " #alias)
226 /* GCC and clang have various useful declarations that can be made with
227 the '__attribute__' syntax. All of the ways we use this do fine if
228 they are omitted for compilers that don't understand it. */
229 #if !(defined __GNUC__ || defined __clang__)
230 # define __attribute__(xyz) /* Ignore */
233 /* At some point during the gcc 2.96 development the `malloc' attribute
234 for functions was introduced. We don't want to use it unconditionally
235 (although this would be possible) since it generates warnings. */
236 #if __GNUC_PREREQ (2,96) || __glibc_clang_has_attribute (__malloc__)
237 # define __attribute_malloc__ __attribute__ ((__malloc__))
239 # define __attribute_malloc__ /* Ignore */
242 /* Tell the compiler which arguments to an allocation function
243 indicate the size of the allocation. */
244 #if __GNUC_PREREQ (4, 3)
245 # define __attribute_alloc_size__(params) \
246 __attribute__ ((__alloc_size__ params))
248 # define __attribute_alloc_size__(params) /* Ignore. */
251 /* At some point during the gcc 2.96 development the `pure' attribute
252 for functions was introduced. We don't want to use it unconditionally
253 (although this would be possible) since it generates warnings. */
254 #if __GNUC_PREREQ (2,96) || __glibc_clang_has_attribute (__pure__)
255 # define __attribute_pure__ __attribute__ ((__pure__))
257 # define __attribute_pure__ /* Ignore */
260 /* This declaration tells the compiler that the value is constant. */
261 #if __GNUC_PREREQ (2,5) || __glibc_clang_has_attribute (__const__)
262 # define __attribute_const__ __attribute__ ((__const__))
264 # define __attribute_const__ /* Ignore */
267 /* At some point during the gcc 3.1 development the `used' attribute
268 for functions was introduced. We don't want to use it unconditionally
269 (although this would be possible) since it generates warnings. */
270 #if __GNUC_PREREQ (3,1) || __glibc_clang_has_attribute (__used__)
271 # define __attribute_used__ __attribute__ ((__used__))
272 # define __attribute_noinline__ __attribute__ ((__noinline__))
274 # define __attribute_used__ __attribute__ ((__unused__))
275 # define __attribute_noinline__ /* Ignore */
278 /* Since version 3.2, gcc allows marking deprecated functions. */
279 #if __GNUC_PREREQ (3,2) || __glibc_clang_has_attribute (__deprecated__)
280 # define __attribute_deprecated__ __attribute__ ((__deprecated__))
282 # define __attribute_deprecated__ /* Ignore */
285 /* Since version 4.5, gcc also allows one to specify the message printed
286 when a deprecated function is used. clang claims to be gcc 4.2, but
287 may also support this feature. */
288 #if __GNUC_PREREQ (4,5) \
289 || __glibc_clang_has_extension (__attribute_deprecated_with_message__)
290 # define __attribute_deprecated_msg__(msg) \
291 __attribute__ ((__deprecated__ (msg)))
293 # define __attribute_deprecated_msg__(msg) __attribute_deprecated__
296 /* At some point during the gcc 2.8 development the `format_arg' attribute
297 for functions was introduced. We don't want to use it unconditionally
298 (although this would be possible) since it generates warnings.
299 If several `format_arg' attributes are given for the same function, in
300 gcc-3.0 and older, all but the last one are ignored. In newer gccs,
301 all designated arguments are considered. */
302 #if __GNUC_PREREQ (2,8) || __glibc_clang_has_attribute (__format_arg__)
303 # define __attribute_format_arg__(x) __attribute__ ((__format_arg__ (x)))
305 # define __attribute_format_arg__(x) /* Ignore */
308 /* At some point during the gcc 2.97 development the `strfmon' format
309 attribute for functions was introduced. We don't want to use it
310 unconditionally (although this would be possible) since it
311 generates warnings. */
312 #if __GNUC_PREREQ (2,97) || __glibc_clang_has_attribute (__format__)
313 # define __attribute_format_strfmon__(a,b) \
314 __attribute__ ((__format__ (__strfmon__, a, b)))
316 # define __attribute_format_strfmon__(a,b) /* Ignore */
319 /* The nonnull function attribute marks pointer parameters that
320 must not be NULL. Do not define __nonnull if it is already defined,
321 for portability when this file is used in Gnulib. */
323 # if __GNUC_PREREQ (3,3) || __glibc_clang_has_attribute (__nonnull__)
324 # define __nonnull(params) __attribute__ ((__nonnull__ params))
326 # define __nonnull(params)
330 /* If fortification mode, we warn about unused results of certain
331 function calls which can lead to problems. */
332 #if __GNUC_PREREQ (3,4) || __glibc_clang_has_attribute (__warn_unused_result__)
333 # define __attribute_warn_unused_result__ \
334 __attribute__ ((__warn_unused_result__))
335 # if defined __USE_FORTIFY_LEVEL && __USE_FORTIFY_LEVEL > 0
336 # define __wur __attribute_warn_unused_result__
339 # define __attribute_warn_unused_result__ /* empty */
342 # define __wur /* Ignore */
345 /* Forces a function to be always inlined. */
346 #if __GNUC_PREREQ (3,2) || __glibc_clang_has_attribute (__always_inline__)
347 /* The Linux kernel defines __always_inline in stddef.h (283d7573), and
348 it conflicts with this definition. Therefore undefine it first to
349 allow either header to be included first. */
350 # undef __always_inline
351 # define __always_inline __inline __attribute__ ((__always_inline__))
353 # undef __always_inline
354 # define __always_inline __inline
357 /* Associate error messages with the source location of the call site rather
358 than with the source location inside the function. */
359 #if __GNUC_PREREQ (4,3) || __glibc_clang_has_attribute (__artificial__)
360 # define __attribute_artificial__ __attribute__ ((__artificial__))
362 # define __attribute_artificial__ /* Ignore */
365 /* GCC 4.3 and above with -std=c99 or -std=gnu99 implements ISO C99
366 inline semantics, unless -fgnu89-inline is used. Using __GNUC_STDC_INLINE__
367 or __GNUC_GNU_INLINE is not a good enough check for gcc because gcc versions
368 older than 4.3 may define these macros and still not guarantee GNU inlining
371 clang++ identifies itself as gcc-4.2, but has support for GNU inlining
372 semantics, that can be checked for by using the __GNUC_STDC_INLINE_ and
373 __GNUC_GNU_INLINE__ macro definitions. */
374 #if (!defined __cplusplus || __GNUC_PREREQ (4,3) \
375 || (defined __clang__ && (defined __GNUC_STDC_INLINE__ \
376 || defined __GNUC_GNU_INLINE__)))
377 # if defined __GNUC_STDC_INLINE__ || defined __cplusplus
378 # define __extern_inline extern __inline __attribute__ ((__gnu_inline__))
379 # define __extern_always_inline \
380 extern __always_inline __attribute__ ((__gnu_inline__))
382 # define __extern_inline extern __inline
383 # define __extern_always_inline extern __always_inline
387 #ifdef __extern_always_inline
388 # define __fortify_function __extern_always_inline __attribute_artificial__
391 /* GCC 4.3 and above allow passing all anonymous arguments of an
392 __extern_always_inline function to some other vararg function. */
393 #if __GNUC_PREREQ (4,3)
394 # define __va_arg_pack() __builtin_va_arg_pack ()
395 # define __va_arg_pack_len() __builtin_va_arg_pack_len ()
398 /* It is possible to compile containing GCC extensions even if GCC is
399 run in pedantic mode if the uses are carefully marked using the
400 `__extension__' keyword. But this is not generally available before
402 #if !(__GNUC_PREREQ (2,8) || defined __clang__)
403 # define __extension__ /* Ignore */
406 /* __restrict is known in EGCS 1.2 and above, and in clang.
407 It works also in C++ mode (outside of arrays), but only when spelled
408 as '__restrict', not 'restrict'. */
409 #if !(__GNUC_PREREQ (2,92) || __clang_major__ >= 3)
410 # if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
411 # define __restrict restrict
413 # define __restrict /* Ignore */
417 /* ISO C99 also allows to declare arrays as non-overlapping. The syntax is
419 GCC 3.1 and clang support this.
420 This syntax is not usable in C++ mode. */
421 #if (__GNUC_PREREQ (3,1) || __clang_major__ >= 3) && !defined __cplusplus
422 # define __restrict_arr __restrict
425 # define __restrict_arr /* Not supported in old GCC. */
427 # if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
428 # define __restrict_arr restrict
430 /* Some other non-C99 compiler. */
431 # define __restrict_arr /* Not supported. */
436 #if (__GNUC__ >= 3) || __glibc_clang_has_builtin (__builtin_expect)
437 # define __glibc_unlikely(cond) __builtin_expect ((cond), 0)
438 # define __glibc_likely(cond) __builtin_expect ((cond), 1)
440 # define __glibc_unlikely(cond) (cond)
441 # define __glibc_likely(cond) (cond)
444 #ifdef __has_attribute
445 # define __glibc_has_attribute(attr) __has_attribute (attr)
447 # define __glibc_has_attribute(attr) 0
450 #if (!defined _Noreturn \
451 && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \
452 && !(__GNUC_PREREQ (4,7) \
453 || (3 < __clang_major__ + (5 <= __clang_minor__))))
454 # if __GNUC_PREREQ (2,8)
455 # define _Noreturn __attribute__ ((__noreturn__))
461 #if __GNUC_PREREQ (8, 0)
462 /* Describes a char array whose address can safely be passed as the first
463 argument to strncpy and strncat, as the char array is not necessarily
464 a NUL-terminated string. */
465 # define __attribute_nonstring__ __attribute__ ((__nonstring__))
467 # define __attribute_nonstring__
470 /* Undefine (also defined in libc-symbols.h). */
471 #undef __attribute_copy__
472 #if __GNUC_PREREQ (9, 0)
473 /* Copies attributes from the declaration or type referenced by
475 # define __attribute_copy__(arg) __attribute__ ((__copy__ (arg)))
477 # define __attribute_copy__(arg)
480 #if (!defined _Static_assert && !defined __cplusplus \
481 && (defined __STDC_VERSION__ ? __STDC_VERSION__ : 0) < 201112 \
482 && (!(__GNUC_PREREQ (4, 6) || __clang_major__ >= 4) \
483 || defined __STRICT_ANSI__))
484 # define _Static_assert(expr, diagnostic) \
485 extern int (*__Static_assert_function (void)) \
486 [!!sizeof (struct { int __error_if_negative: (expr) ? 2 : -1; })]
489 /* The #ifndef lets Gnulib avoid including these on non-glibc
490 platforms, where the includes typically do not exist. */
492 # include <bits/wordsize.h>
493 # include <bits/long-double.h>
496 #if __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
499 /* Alias name defined automatically. */
500 # define __LDBL_REDIR(name, proto) ... unused__ldbl_redir
501 # define __LDBL_REDIR_DECL(name) \
502 extern __typeof (name) name __asm (__ASMNAME ("__" #name "ieee128"));
504 /* Alias name defined automatically, with leading underscores. */
505 # define __LDBL_REDIR2_DECL(name) \
506 extern __typeof (__##name) __##name \
507 __asm (__ASMNAME ("__" #name "ieee128"));
509 /* Alias name defined manually. */
510 # define __LDBL_REDIR1(name, proto, alias) ... unused__ldbl_redir1
511 # define __LDBL_REDIR1_DECL(name, alias) \
512 extern __typeof (name) name __asm (__ASMNAME (#alias));
514 # define __LDBL_REDIR1_NTH(name, proto, alias) \
515 __REDIRECT_NTH (name, proto, alias)
516 # define __REDIRECT_NTH_LDBL(name, proto, alias) \
517 __LDBL_REDIR1_NTH (name, proto, __##alias##ieee128)
520 # define __REDIRECT_LDBL(name, proto, alias) ... unused__redirect_ldbl
521 # define __LDBL_REDIR_NTH(name, proto) ... unused__ldbl_redir_nth
524 _Static_assert (0, "IEEE 128-bits long double requires redirection on this platform");
526 #elif defined __LONG_DOUBLE_MATH_OPTIONAL && defined __NO_LONG_DOUBLE_MATH
527 # define __LDBL_COMPAT 1
529 # define __LDBL_REDIR1(name, proto, alias) __REDIRECT (name, proto, alias)
530 # define __LDBL_REDIR(name, proto) \
531 __LDBL_REDIR1 (name, proto, __nldbl_##name)
532 # define __LDBL_REDIR1_NTH(name, proto, alias) __REDIRECT_NTH (name, proto, alias)
533 # define __LDBL_REDIR_NTH(name, proto) \
534 __LDBL_REDIR1_NTH (name, proto, __nldbl_##name)
535 # define __LDBL_REDIR2_DECL(name) \
536 extern __typeof (__##name) __##name __asm (__ASMNAME ("__nldbl___" #name));
537 # define __LDBL_REDIR1_DECL(name, alias) \
538 extern __typeof (name) name __asm (__ASMNAME (#alias));
539 # define __LDBL_REDIR_DECL(name) \
540 extern __typeof (name) name __asm (__ASMNAME ("__nldbl_" #name));
541 # define __REDIRECT_LDBL(name, proto, alias) \
542 __LDBL_REDIR1 (name, proto, __nldbl_##alias)
543 # define __REDIRECT_NTH_LDBL(name, proto, alias) \
544 __LDBL_REDIR1_NTH (name, proto, __nldbl_##alias)
547 #if (!defined __LDBL_COMPAT && __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 0) \
548 || !defined __REDIRECT
549 # define __LDBL_REDIR1(name, proto, alias) name proto
550 # define __LDBL_REDIR(name, proto) name proto
551 # define __LDBL_REDIR1_NTH(name, proto, alias) name proto __THROW
552 # define __LDBL_REDIR_NTH(name, proto) name proto __THROW
553 # define __LDBL_REDIR2_DECL(name)
554 # define __LDBL_REDIR_DECL(name)
556 # define __REDIRECT_LDBL(name, proto, alias) __REDIRECT (name, proto, alias)
557 # define __REDIRECT_NTH_LDBL(name, proto, alias) \
558 __REDIRECT_NTH (name, proto, alias)
562 /* __glibc_macro_warning (MESSAGE) issues warning MESSAGE. This is
563 intended for use in preprocessor macros.
565 Note: MESSAGE must be a _single_ string; concatenation of string
566 literals is not supported. */
567 #if __GNUC_PREREQ (4,8) || __glibc_clang_prereq (3,5)
568 # define __glibc_macro_warning1(message) _Pragma (#message)
569 # define __glibc_macro_warning(message) \
570 __glibc_macro_warning1 (GCC warning message)
572 # define __glibc_macro_warning(msg)
575 /* Generic selection (ISO C11) is a C-only feature, available in GCC
576 since version 4.9. Previous versions do not provide generic
577 selection, even though they might set __STDC_VERSION__ to 201112L,
578 when in -std=c11 mode. Thus, we must check for !defined __GNUC__
579 when testing __STDC_VERSION__ for generic selection support.
580 On the other hand, Clang also defines __GNUC__, so a clang-specific
581 check is required to enable the use of generic selection. */
582 #if !defined __cplusplus \
583 && (__GNUC_PREREQ (4, 9) \
584 || __glibc_clang_has_extension (c_generic_selections) \
585 || (!defined __GNUC__ && defined __STDC_VERSION__ \
586 && __STDC_VERSION__ >= 201112L))
587 # define __HAVE_GENERIC_SELECTION 1
589 # define __HAVE_GENERIC_SELECTION 0
592 #if __GNUC_PREREQ (10, 0)
593 /* Designates a 1-based positional argument ref-index of pointer type
594 that can be used to access size-index elements of the pointed-to
595 array according to access mode, or at least one element when
596 size-index is not provided:
597 access (access-mode, <ref-index> [, <size-index>]) */
598 #define __attr_access(x) __attribute__ ((__access__ x))
600 # define __attr_access(x)
603 /* Specify that a function such as setjmp or vfork may return
605 #if __GNUC_PREREQ (4, 1)
606 # define __attribute_returns_twice__ __attribute__ ((__returns_twice__))
608 # define __attribute_returns_twice__ /* Ignore. */
611 #endif /* sys/cdefs.h */