1 /* A substitute for POSIX 2008 <stddef.h>, for platforms that have issues.
2
3 Copyright (C) 2009-2023 Free Software Foundation, Inc.
4
5 This file is free software: you can redistribute it and/or modify
6 it under the terms of the GNU Lesser General Public License as
7 published by the Free Software Foundation; either version 2.1 of the
8 License, or (at your option) any later version.
9
10 This file 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 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public License
16 along with this program. If not, see <https://www.gnu.org/licenses/>. */
17
18 /* Written by Eric Blake. */
19
20 /*
21 * POSIX 2008 <stddef.h> for platforms that have issues.
22 * <https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/stddef.h.html>
23 */
24
25 #if __GNUC__ >= 3
26 @PRAGMA_SYSTEM_HEADER@
27 #endif
28 @PRAGMA_COLUMNS@
29
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. */
39
40 # if !(defined _@GUARD_PREFIX@_STDDEF_H && defined _GL_STDDEF_WINT_T)
41 # ifdef __need_wint_t
42 # define _GL_STDDEF_WINT_T
43 # endif
44 # @INCLUDE_NEXT@ @NEXT_STDDEF_H@
45 /* On TinyCC, make sure that the macros that indicate the special invocation
46 convention get undefined. */
47 # undef __need_wchar_t
48 # undef __need_size_t
49 # undef __need_ptrdiff_t
50 # undef __need_NULL
51 # undef __need_wint_t
52 # endif
53
54 #else
55 /* Normal invocation convention. */
56
57 # ifndef _@GUARD_PREFIX@_STDDEF_H
58
59 /* On AIX 7.2, with xlc in 64-bit mode, <stddef.h> defines max_align_t to a
60 type with alignment 4, but 'long' has alignment 8. */
61 # if defined _AIX && defined __LP64__
62 # if !GNULIB_defined_max_align_t
63 # ifdef _MAX_ALIGN_T
64 /* /usr/include/stddef.h has already defined max_align_t. Override it. */
65 typedef long rpl_max_align_t;
66 # define max_align_t rpl_max_align_t
67 # else
68 /* Prevent /usr/include/stddef.h from defining max_align_t. */
69 typedef long max_align_t;
70 # define _MAX_ALIGN_T
71 # endif
72 # define GNULIB_defined_max_align_t 1
73 # endif
74 # endif
75
76 /* The include_next requires a split double-inclusion guard. */
77
78 # @INCLUDE_NEXT@ @NEXT_STDDEF_H@
79
80 /* On NetBSD 5.0, the definition of NULL lacks proper parentheses. */
81 # if (@REPLACE_NULL@ \
82 && (!defined _@GUARD_PREFIX@_STDDEF_H || defined _GL_STDDEF_WINT_T))
83 # undef NULL
84 # ifdef __cplusplus
85 /* ISO C++ says that the macro NULL must expand to an integer constant
86 expression, hence '((void *) 0)' is not allowed in C++. */
87 # if __GNUG__ >= 3
88 /* GNU C++ has a __null macro that behaves like an integer ('int' or
89 'long') but has the same size as a pointer. Use that, to avoid
90 warnings. */
91 # define NULL __null
92 # else
93 # define NULL 0L
94 # endif
95 # else
96 # define NULL ((void *) 0)
97 # endif
98 # endif
99
100 # ifndef _@GUARD_PREFIX@_STDDEF_H
101 # define _@GUARD_PREFIX@_STDDEF_H
102
103 /* Some platforms lack wchar_t. */
104 #if !@HAVE_WCHAR_T@
105 # define wchar_t int
106 #endif
107
108 /* Some platforms lack max_align_t. The check for _GCC_MAX_ALIGN_T is
109 a hack in case the configure-time test was done with g++ even though
110 we are currently compiling with gcc.
111 On MSVC, max_align_t is defined only in C++ mode, after <cstddef> was
112 included. Its definition is good since it has an alignment of 8 (on x86
113 and x86_64).
114 Similarly on OS/2 kLIBC. */
115 #if (defined _MSC_VER || (defined __KLIBC__ && !defined __LIBCN__)) \
116 && defined __cplusplus
117 # include <cstddef>
118 #else
119 # if ! (@HAVE_MAX_ALIGN_T@ || (defined _GCC_MAX_ALIGN_T && !defined __clang__))
120 # if !GNULIB_defined_max_align_t
121 /* On the x86, the maximum storage alignment of double, long, etc. is 4,
122 but GCC's C11 ABI for x86 says that max_align_t has an alignment of 8,
123 and the C11 standard allows this. Work around this problem by
124 using __alignof__ (which returns 8 for double) rather than _Alignof
125 (which returns 4), and align each union member accordingly. */
126 # if defined __GNUC__ || (__clang_major__ >= 4)
127 # define _GL_STDDEF_ALIGNAS(type) \
128 __attribute__ ((__aligned__ (__alignof__ (type))))
129 # else
130 # define _GL_STDDEF_ALIGNAS(type) /* */
131 # endif
132 typedef union
133 {
134 char *__p _GL_STDDEF_ALIGNAS (char *);
135 double __d _GL_STDDEF_ALIGNAS (double);
136 long double __ld _GL_STDDEF_ALIGNAS (long double);
137 long int __i _GL_STDDEF_ALIGNAS (long int);
138 } rpl_max_align_t;
139 # define max_align_t rpl_max_align_t
140 # define GNULIB_defined_max_align_t 1
141 # endif
142 # endif
143 #endif
144
145 # endif /* _@GUARD_PREFIX@_STDDEF_H */
146 # endif /* _@GUARD_PREFIX@_STDDEF_H */
147 #endif /* __need_XXX */