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 and ISO C 23 <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 _@GUARD_PREFIX@_STDDEF_WINT_T)
41 # ifdef __need_wint_t
42 # define _@GUARD_PREFIX@_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__ && !@HAVE_MAX_ALIGN_T@
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 __CLANG_MAX_ALIGN_T_DEFINED
73 # define GNULIB_defined_max_align_t 1
74 # endif
75 # endif
76
77 /* The include_next requires a split double-inclusion guard. */
78
79 # @INCLUDE_NEXT@ @NEXT_STDDEF_H@
80
81 /* On NetBSD 5.0, the definition of NULL lacks proper parentheses. */
82 # if (@REPLACE_NULL@ \
83 && (!defined _@GUARD_PREFIX@_STDDEF_H || defined _@GUARD_PREFIX@_STDDEF_WINT_T))
84 # undef NULL
85 # ifdef __cplusplus
86 /* ISO C++ says that the macro NULL must expand to an integer constant
87 expression, hence '((void *) 0)' is not allowed in C++. */
88 # if __GNUG__ >= 3
89 /* GNU C++ has a __null macro that behaves like an integer ('int' or
90 'long') but has the same size as a pointer. Use that, to avoid
91 warnings. */
92 # define NULL __null
93 # else
94 # define NULL 0L
95 # endif
96 # else
97 # define NULL ((void *) 0)
98 # endif
99 # endif
100
101 # ifndef _@GUARD_PREFIX@_STDDEF_H
102 # define _@GUARD_PREFIX@_STDDEF_H
103
104 /* This file uses _Noreturn, _GL_ATTRIBUTE_NOTHROW. */
105 #if !_GL_CONFIG_H_INCLUDED
106 #error "Please include config.h first."
107 #endif
108
109 /* _GL_ATTRIBUTE_NOTHROW declares that the function does not throw exceptions.
110 */
111 #ifndef _GL_ATTRIBUTE_NOTHROW
112 # if defined __cplusplus
113 # if (__GNUC__ + (__GNUC_MINOR__ >= 8) > 2) || __clang_major >= 4
114 # if __cplusplus >= 201103L
115 # define _GL_ATTRIBUTE_NOTHROW noexcept (true)
116 # else
117 # define _GL_ATTRIBUTE_NOTHROW throw ()
118 # endif
119 # else
120 # define _GL_ATTRIBUTE_NOTHROW
121 # endif
122 # else
123 # if (__GNUC__ + (__GNUC_MINOR__ >= 3) > 3) || defined __clang__
124 # define _GL_ATTRIBUTE_NOTHROW __attribute__ ((__nothrow__))
125 # else
126 # define _GL_ATTRIBUTE_NOTHROW
127 # endif
128 # endif
129 #endif
130
131 /* Some platforms lack wchar_t. */
132 #if !@HAVE_WCHAR_T@
133 # define wchar_t int
134 #endif
135
136 /* Some platforms lack max_align_t. The check for _GCC_MAX_ALIGN_T is
137 a hack in case the configure-time test was done with g++ even though
138 we are currently compiling with gcc.
139 On MSVC, max_align_t is defined only in C++ mode, after <cstddef> was
140 included. Its definition is good since it has an alignment of 8 (on x86
141 and x86_64).
142 Similarly on OS/2 kLIBC. */
143 #if (defined _MSC_VER || (defined __KLIBC__ && !defined __LIBCN__)) \
144 && defined __cplusplus
145 # include <cstddef>
146 #else
147 # if ! (@HAVE_MAX_ALIGN_T@ || (defined _GCC_MAX_ALIGN_T && !defined __clang__))
148 # if !GNULIB_defined_max_align_t
149 /* On the x86, the maximum storage alignment of double, long, etc. is 4,
150 but GCC's C11 ABI for x86 says that max_align_t has an alignment of 8,
151 and the C11 standard allows this. Work around this problem by
152 using __alignof__ (which returns 8 for double) rather than _Alignof
153 (which returns 4), and align each union member accordingly. */
154 # if defined __GNUC__ || (__clang_major__ >= 4)
155 # define _GL_STDDEF_ALIGNAS(type) \
156 __attribute__ ((__aligned__ (__alignof__ (type))))
157 # else
158 # define _GL_STDDEF_ALIGNAS(type) /* */
159 # endif
160 typedef union
161 {
162 char *__p _GL_STDDEF_ALIGNAS (char *);
163 double __d _GL_STDDEF_ALIGNAS (double);
164 long double __ld _GL_STDDEF_ALIGNAS (long double);
165 long int __i _GL_STDDEF_ALIGNAS (long int);
166 } rpl_max_align_t;
167 # define max_align_t rpl_max_align_t
168 # define __CLANG_MAX_ALIGN_T_DEFINED
169 # define GNULIB_defined_max_align_t 1
170 # endif
171 # endif
172 #endif
173
174 /* ISO C 23 ยง 7.21.1 The unreachable macro */
175 #ifndef unreachable
176
177 /* Code borrowed from verify.h. */
178 # ifndef _GL_HAS_BUILTIN_UNREACHABLE
179 # if defined __clang_major__ && __clang_major__ < 5
180 # define _GL_HAS_BUILTIN_UNREACHABLE 0
181 # elif 4 < __GNUC__ + (5 <= __GNUC_MINOR__)
182 # define _GL_HAS_BUILTIN_UNREACHABLE 1
183 # elif defined __has_builtin
184 # define _GL_HAS_BUILTIN_UNREACHABLE __has_builtin (__builtin_unreachable)
185 # else
186 # define _GL_HAS_BUILTIN_UNREACHABLE 0
187 # endif
188 # endif
189
190 # if _GL_HAS_BUILTIN_UNREACHABLE
191 # define unreachable() __builtin_unreachable ()
192 # elif 1200 <= _MSC_VER
193 # define unreachable() __assume (0)
194 # else
195 /* Declare abort(), without including <stdlib.h>. */
196 extern
197 # if defined __cplusplus
198 "C"
199 # endif
200 _Noreturn
201 void abort (void)
202 # if defined __cplusplus && (__GLIBC__ >= 2)
203 _GL_ATTRIBUTE_NOTHROW
204 # endif
205 ;
206 # define unreachable() abort ()
207 # endif
208
209 #endif
210
211 # endif /* _@GUARD_PREFIX@_STDDEF_H */
212 # endif /* _@GUARD_PREFIX@_STDDEF_H */
213 #endif /* __need_XXX */