1 /* A substitute for POSIX 2008 <stddef.h>, for platforms that have issues.
3 Copyright (C) 2009-2021 Free Software Foundation, Inc.
5 This program 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)
10 This program 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 You should have received a copy of the GNU General Public License
16 along with this program; if not, see <https://www.gnu.org/licenses/>. */
18 /* Written by Eric Blake. */
21 * POSIX 2008 <stddef.h> for platforms that have issues.
22 * <https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/stddef.h.html>
26 @PRAGMA_SYSTEM_HEADER@
30 #if defined __need_wchar_t || defined __need_size_t \
31 || defined __need_ptrdiff_t || defined __need_NULL \
32 || defined __need_wint_t
33 /* Special invocation convention inside gcc header files. In
34 particular, gcc provides a version of <stddef.h> that blindly
35 redefines NULL even when __need_wint_t was defined, even though
36 wint_t is not normally provided by <stddef.h>. Hence, we must
37 remember if special invocation has ever been used to obtain wint_t,
38 in which case we need to clean up NULL yet again. */
40 # if !(defined _@GUARD_PREFIX@_STDDEF_H && defined _GL_STDDEF_WINT_T)
42 # define _GL_STDDEF_WINT_T
44 # @INCLUDE_NEXT@ @NEXT_STDDEF_H@
48 /* Normal invocation convention. */
50 # ifndef _@GUARD_PREFIX@_STDDEF_H
52 /* On AIX 7.2, with xlc in 64-bit mode, <stddef.h> defines max_align_t to a
53 type with alignment 4, but 'long' has alignment 8. */
54 # if defined _AIX && defined _ARCH_PPC64
55 # if !GNULIB_defined_max_align_t
57 /* /usr/include/stddef.h has already defined max_align_t. Override it. */
58 typedef long rpl_max_align_t
;
59 # define max_align_t rpl_max_align_t
61 /* Prevent /usr/include/stddef.h from defining max_align_t. */
62 typedef long max_align_t
;
65 # define GNULIB_defined_max_align_t 1
69 /* The include_next requires a split double-inclusion guard. */
71 # @INCLUDE_NEXT@ @NEXT_STDDEF_H@
73 /* On NetBSD 5.0, the definition of NULL lacks proper parentheses. */
74 # if (@REPLACE_NULL@ \
75 && (!defined _@GUARD_PREFIX@_STDDEF_H || defined _GL_STDDEF_WINT_T))
78 /* ISO C++ says that the macro NULL must expand to an integer constant
79 expression, hence '((void *) 0)' is not allowed in C++. */
81 /* GNU C++ has a __null macro that behaves like an integer ('int' or
82 'long') but has the same size as a pointer. Use that, to avoid
89 # define NULL ((void *) 0)
93 # ifndef _@GUARD_PREFIX@_STDDEF_H
94 # define _@GUARD_PREFIX@_STDDEF_H
96 /* Some platforms lack wchar_t. */
101 /* Some platforms lack max_align_t. The check for _GCC_MAX_ALIGN_T is
102 a hack in case the configure-time test was done with g++ even though
103 we are currently compiling with gcc.
104 On MSVC, max_align_t is defined only in C++ mode, after <cstddef> was
105 included. Its definition is good since it has an alignment of 8 (on x86
107 #if defined _MSC_VER && defined __cplusplus
110 # if ! (@HAVE_MAX_ALIGN_T@ || defined _GCC_MAX_ALIGN_T)
111 # if !GNULIB_defined_max_align_t
112 /* On the x86, the maximum storage alignment of double, long, etc. is 4,
113 but GCC's C11 ABI for x86 says that max_align_t has an alignment of 8,
114 and the C11 standard allows this. Work around this problem by
115 using __alignof__ (which returns 8 for double) rather than _Alignof
116 (which returns 4), and align each union member accordingly. */
117 # if defined __GNUC__ || (__clang_major__ >= 4)
118 # define _GL_STDDEF_ALIGNAS(type) \
119 __attribute__ ((__aligned__ (__alignof__ (type))))
121 # define _GL_STDDEF_ALIGNAS(type) /* */
125 char *__p
_GL_STDDEF_ALIGNAS (char *);
126 double __d
_GL_STDDEF_ALIGNAS (double);
127 long double __ld
_GL_STDDEF_ALIGNAS (long double);
128 long int __i
_GL_STDDEF_ALIGNAS (long int);
130 # define max_align_t rpl_max_align_t
131 # define GNULIB_defined_max_align_t 1
136 # endif /* _@GUARD_PREFIX@_STDDEF_H */
137 # endif /* _@GUARD_PREFIX@_STDDEF_H */
138 #endif /* __need_XXX */