1 /* A substitute for POSIX 2008 <stddef.h>, for platforms that have issues. 2 3 Copyright (C) 2009-2020 Free Software Foundation, Inc. 4 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) 8 any later version. 9 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. 14 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/>. */ 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 # endif 46 47 #else 48 /* Normal invocation convention. */ 49 50 # ifndef _@GUARD_PREFIX@_STDDEF_H 51 52 /* The include_next requires a split double-inclusion guard. */ 53 54 # @INCLUDE_NEXT@ @NEXT_STDDEF_H@ 55 56 /* On NetBSD 5.0, the definition of NULL lacks proper parentheses. */ 57 # if (@REPLACE_NULL@ \ 58 && (!defined _@GUARD_PREFIX@_STDDEF_H || defined _GL_STDDEF_WINT_T)) 59 # undef NULL 60 # ifdef __cplusplus 61 /* ISO C++ says that the macro NULL must expand to an integer constant 62 expression, hence '((void *) 0)' is not allowed in C++. */ 63 # if __GNUG__ >= 3 64 /* GNU C++ has a __null macro that behaves like an integer ('int' or 65 'long') but has the same size as a pointer. Use that, to avoid 66 warnings. */ 67 # define NULL __null 68 # else 69 # define NULL 0L 70 # endif 71 # else 72 # define NULL ((void *) 0) 73 # endif 74 # endif 75 76 # ifndef _@GUARD_PREFIX@_STDDEF_H 77 # define _@GUARD_PREFIX@_STDDEF_H 78 79 /* Some platforms lack wchar_t. */ 80 #if !@HAVE_WCHAR_T@ 81 # define wchar_t int 82 #endif 83 84 /* Some platforms lack max_align_t. The check for _GCC_MAX_ALIGN_T is 85 a hack in case the configure-time test was done with g++ even though 86 we are currently compiling with gcc. 87 On MSVC, max_align_t is defined only in C++ mode, after <cstddef> was 88 included. Its definition is good since it has an alignment of 8 (on x86 89 and x86_64). */ 90 #if defined _MSC_VER && defined __cplusplus 91 # include <cstddef> 92 #else 93 # if ! (@HAVE_MAX_ALIGN_T@ || defined _GCC_MAX_ALIGN_T) 94 # if !GNULIB_defined_max_align_t 95 /* On the x86, the maximum storage alignment of double, long, etc. is 4, 96 but GCC's C11 ABI for x86 says that max_align_t has an alignment of 8, 97 and the C11 standard allows this. Work around this problem by 98 using __alignof__ (which returns 8 for double) rather than _Alignof 99 (which returns 4), and align each union member accordingly. */ 100 # ifdef __GNUC__ 101 # define _GL_STDDEF_ALIGNAS(type) \ 102 __attribute__ ((__aligned__ (__alignof__ (type)))) 103 # else 104 # define _GL_STDDEF_ALIGNAS(type) /* */ 105 # endif 106 typedef union 107 { 108 char *__p _GL_STDDEF_ALIGNAS (char *); 109 double __d _GL_STDDEF_ALIGNAS (double); 110 long double __ld _GL_STDDEF_ALIGNAS (long double); 111 long int __i _GL_STDDEF_ALIGNAS (long int); 112 } rpl_max_align_t; 113 # define max_align_t rpl_max_align_t 114 # define GNULIB_defined_max_align_t 1 115 # endif 116 # endif 117 #endif 118 119 # endif /* _@GUARD_PREFIX@_STDDEF_H */ 120 # endif /* _@GUARD_PREFIX@_STDDEF_H */ 121 #endif /* __need_XXX */ 122