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emacs/lib/stddef.in.h
Paul Eggert 124a7951f4 Update from Gnulib
This incorporates:
2020-08-11 Use expression statements also on clang
2020-08-10 Use many __attribute__s with clang
2020-08-09 Use attribute __aligned__ with clang
2020-08-09 Use __alignof__ with clang
2020-08-09 ignore-value: Simplify on clang
2020-08-09 Use __typeof__ with clang
2020-08-09 intprops: Fix typo in comment
2020-08-09 Silence warnings from clang 10 with -Wimplicit-fallthrough
2020-08-09 count-one-bits: Use __builtin_popcount{,l,ll} on clang
2020-08-09 string: Fix build error in C++ mode with clang
2020-08-09 Add ability to emit user-defined diagnostics with clang
2020-08-07 alloca: No need to compile alloca.c with clang
2020-08-06 Use __builtin_assume with clang
* lib/alloca.in.h, lib/arg-nonnull.h, lib/c++defs.h, lib/cdefs.h:
* lib/count-one-bits.h, lib/dirent.in.h, lib/ignore-value.h:
* lib/intprops.h, lib/malloca.h, lib/regex_internal.h:
* lib/stdalign.in.h, lib/stddef.in.h, lib/stdio.in.h:
* lib/stdlib.in.h, lib/string.in.h, lib/verify.h, lib/warn-on-use.h:
* m4/gnulib-common.m4, m4/stddef_h.m4, m4/stdint.m4:
Copy from Gnulib.
2020-08-11 11:07:28 -07:00

122 lines
4.1 KiB
C

/* A substitute for POSIX 2008 <stddef.h>, for platforms that have issues.
Copyright (C) 2009-2020 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, see <https://www.gnu.org/licenses/>. */
/* Written by Eric Blake. */
/*
* POSIX 2008 <stddef.h> for platforms that have issues.
* <https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/stddef.h.html>
*/
#if __GNUC__ >= 3
@PRAGMA_SYSTEM_HEADER@
#endif
@PRAGMA_COLUMNS@
#if defined __need_wchar_t || defined __need_size_t \
|| defined __need_ptrdiff_t || defined __need_NULL \
|| defined __need_wint_t
/* Special invocation convention inside gcc header files. In
particular, gcc provides a version of <stddef.h> that blindly
redefines NULL even when __need_wint_t was defined, even though
wint_t is not normally provided by <stddef.h>. Hence, we must
remember if special invocation has ever been used to obtain wint_t,
in which case we need to clean up NULL yet again. */
# if !(defined _@GUARD_PREFIX@_STDDEF_H && defined _GL_STDDEF_WINT_T)
# ifdef __need_wint_t
# define _GL_STDDEF_WINT_T
# endif
# @INCLUDE_NEXT@ @NEXT_STDDEF_H@
# endif
#else
/* Normal invocation convention. */
# ifndef _@GUARD_PREFIX@_STDDEF_H
/* The include_next requires a split double-inclusion guard. */
# @INCLUDE_NEXT@ @NEXT_STDDEF_H@
/* On NetBSD 5.0, the definition of NULL lacks proper parentheses. */
# if (@REPLACE_NULL@ \
&& (!defined _@GUARD_PREFIX@_STDDEF_H || defined _GL_STDDEF_WINT_T))
# undef NULL
# ifdef __cplusplus
/* ISO C++ says that the macro NULL must expand to an integer constant
expression, hence '((void *) 0)' is not allowed in C++. */
# if __GNUG__ >= 3
/* GNU C++ has a __null macro that behaves like an integer ('int' or
'long') but has the same size as a pointer. Use that, to avoid
warnings. */
# define NULL __null
# else
# define NULL 0L
# endif
# else
# define NULL ((void *) 0)
# endif
# endif
# ifndef _@GUARD_PREFIX@_STDDEF_H
# define _@GUARD_PREFIX@_STDDEF_H
/* Some platforms lack wchar_t. */
#if !@HAVE_WCHAR_T@
# define wchar_t int
#endif
/* Some platforms lack max_align_t. The check for _GCC_MAX_ALIGN_T is
a hack in case the configure-time test was done with g++ even though
we are currently compiling with gcc.
On MSVC, max_align_t is defined only in C++ mode, after <cstddef> was
included. Its definition is good since it has an alignment of 8 (on x86
and x86_64). */
#if defined _MSC_VER && defined __cplusplus
# include <cstddef>
#else
# if ! (@HAVE_MAX_ALIGN_T@ || defined _GCC_MAX_ALIGN_T)
# if !GNULIB_defined_max_align_t
/* On the x86, the maximum storage alignment of double, long, etc. is 4,
but GCC's C11 ABI for x86 says that max_align_t has an alignment of 8,
and the C11 standard allows this. Work around this problem by
using __alignof__ (which returns 8 for double) rather than _Alignof
(which returns 4), and align each union member accordingly. */
# if defined __GNUC__ || (__clang_major__ >= 4)
# define _GL_STDDEF_ALIGNAS(type) \
__attribute__ ((__aligned__ (__alignof__ (type))))
# else
# define _GL_STDDEF_ALIGNAS(type) /* */
# endif
typedef union
{
char *__p _GL_STDDEF_ALIGNAS (char *);
double __d _GL_STDDEF_ALIGNAS (double);
long double __ld _GL_STDDEF_ALIGNAS (long double);
long int __i _GL_STDDEF_ALIGNAS (long int);
} rpl_max_align_t;
# define max_align_t rpl_max_align_t
# define GNULIB_defined_max_align_t 1
# endif
# endif
#endif
# endif /* _@GUARD_PREFIX@_STDDEF_H */
# endif /* _@GUARD_PREFIX@_STDDEF_H */
#endif /* __need_XXX */