glibc/misc/sys/cdefs.h

254 lines
8.2 KiB
C++

/* Copyright (C) 1992-2001, 2002 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#ifndef _SYS_CDEFS_H
#define _SYS_CDEFS_H 1
/* We are almost always included from features.h. */
#ifndef _FEATURES_H
# include <features.h>
#endif
/* The GNU libc does not support any K&R compilers or the traditional mode
of ISO C compilers anymore. Check for some of the combinations not
anymore supported. */
#if defined __GNUC__ && !defined __STDC__
# error "You need a ISO C conforming compiler to use the glibc headers"
#endif
/* Some user header file might have defined this before. */
#undef __P
#undef __PMT
#ifdef __GNUC__
/* GCC can always grok prototypes. For C++ programs we add throw()
to help it optimize the function calls. But this works only with
gcc 2.8.x and egcs. */
# if defined __cplusplus && __GNUC_PREREQ (2,8)
# define __THROW throw ()
# else
# define __THROW
# endif
# define __P(args) args __THROW
/* This macro will be used for functions which might take C++ callback
functions. */
# define __PMT(args) args
#else /* Not GCC. */
# define __inline /* No inline functions. */
# define __THROW
# define __P(args) args
# define __PMT(args) args
# define __const const
# define __signed signed
# define __volatile volatile
#endif /* GCC. */
/* For these things, GCC behaves the ANSI way normally,
and the non-ANSI way under -traditional. */
#define __CONCAT(x,y) x ## y
#define __STRING(x) #x
/* This is not a typedef so `const __ptr_t' does the right thing. */
#define __ptr_t void *
#define __long_double_t long double
/* C++ needs to know that types and declarations are C, not C++. */
#ifdef __cplusplus
# define __BEGIN_DECLS extern "C" {
# define __END_DECLS }
#else
# define __BEGIN_DECLS
# define __END_DECLS
#endif
/* The standard library needs the functions from the ISO C90 standard
in the std namespace. At the same time we want to be safe for
future changes and we include the ISO C99 code in the non-standard
namespace __c99. The C++ wrapper header take case of adding the
definitions to the global namespace. */
#if defined __cplusplus && defined _GLIBCPP_USE_NAMESPACES
# define __BEGIN_NAMESPACE_STD namespace std {
# define __END_NAMESPACE_STD }
# define __USING_NAMESPACE_STD(name) using std::name;
# define __BEGIN_NAMESPACE_C99 namespace __c99 {
# define __END_NAMESPACE_C99 }
# define __USING_NAMESPACE_C99(name) using __c99::name;
#else
/* For compatibility we do not add the declarations into any
namespace. They will end up in the global namespace which is what
old code expects. */
# define __BEGIN_NAMESPACE_STD
# define __END_NAMESPACE_STD
# define __USING_NAMESPACE_STD(name)
# define __BEGIN_NAMESPACE_C99
# define __END_NAMESPACE_C99
# define __USING_NAMESPACE_C99(name)
#endif
/* Support for bounded pointers. */
#ifndef __BOUNDED_POINTERS__
# define __bounded /* nothing */
# define __unbounded /* nothing */
# define __ptrvalue /* nothing */
#endif
/* Support for flexible arrays. */
#if __GNUC_PREREQ (2,97)
/* GCC 2.97 supports C99 flexible array members. */
# define __flexarr []
#else
# ifdef __GNUC__
# define __flexarr [0]
# else
# if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
# define __flexarr []
# else
/* Some other non-C99 compiler. Approximate with [1]. */
# define __flexarr [1]
# endif
# endif
#endif
/* __asm__ ("xyz") is used throughout the headers to rename functions
at the assembly language level. This is wrapped by the __REDIRECT
macro, in order to support compilers that can do this some other
way. When compilers don't support asm-names at all, we have to do
preprocessor tricks instead (which don't have exactly the right
semantics, but it's the best we can do).
Example:
int __REDIRECT(setpgrp, (__pid_t pid, __pid_t pgrp), setpgid); */
#if defined __GNUC__ && __GNUC__ >= 2
# define __REDIRECT(name, proto, alias) name proto __asm__ (__ASMNAME (#alias))
# define __ASMNAME(cname) __ASMNAME2 (__USER_LABEL_PREFIX__, cname)
# define __ASMNAME2(prefix, cname) __STRING (prefix) cname
/*
#elif __SOME_OTHER_COMPILER__
# define __REDIRECT(name, proto, alias) name proto; \
_Pragma("let " #name " = " #alias)
*/
#endif
/* GCC has various useful declarations that can be made with the
`__attribute__' syntax. All of the ways we use this do fine if
they are omitted for compilers that don't understand it. */
#if !defined __GNUC__ || __GNUC__ < 2
# define __attribute__(xyz) /* Ignore */
#endif
/* At some point during the gcc 2.96 development the `malloc' attribute
for functions was introduced. We don't want to use it unconditionally
(although this would be possible) since it generates warnings. */
#if __GNUC_PREREQ (2,96)
# define __attribute_malloc__ __attribute__ ((__malloc__))
#else
# define __attribute_malloc__ /* Ignore */
#endif
/* At some point during the gcc 2.96 development the `pure' attribute
for functions was introduced. We don't want to use it unconditionally
(although this would be possible) since it generates warnings. */
#if __GNUC_PREREQ (2,96)
# define __attribute_pure__ __attribute__ ((__pure__))
#else
# define __attribute_pure__ /* Ignore */
#endif
/* At some point during the gcc 3.1 development the `used' attribute
for functions was introduced. We don't want to use it unconditionally
(although this would be possible) since it generates warnings. */
#if __GNUC_PREREQ (3,1)
# define __attribute_used__ __attribute__ ((__used__))
# define __attribute_noinline__ __attribute__ ((__noinline__))
#else
# define __attribute_used__ __attribute__ ((__unused__))
# define __attribute_noinline__ /* Ignore */
#endif
/* At some point during the gcc 2.8 development the `format_arg' attribute
for functions was introduced. We don't want to use it unconditionally
(although this would be possible) since it generates warnings.
If several `format_arg' attributes are given for the same function, in
gcc-3.0 and older, all but the last one are ignored. In newer gccs,
all designated arguments are considered. */
#if __GNUC_PREREQ (2,8)
# define __attribute_format_arg__(x) __attribute__ ((__format_arg__ (x)))
#else
# define __attribute_format_arg__(x) /* Ignore */
#endif
/* At some point during the gcc 2.97 development the `strfmon' format
attribute for functions was introduced. We don't want to use it
unconditionally (although this would be possible) since it
generates warnings. */
#if __GNUC_PREREQ (2,97)
# define __attribute_format_strfmon__(a,b) \
__attribute__ ((__format__ (__strfmon__, a, b)))
#else
# define __attribute_format_strfmon__(a,b) /* Ignore */
#endif
/* It is possible to compile containing GCC extensions even if GCC is
run in pedantic mode if the uses are carefully marked using the
`__extension__' keyword. But this is not generally available before
version 2.8. */
#if !__GNUC_PREREQ (2,8)
# define __extension__ /* Ignore */
#endif
/* __restrict is known in EGCS 1.2 and above. */
#if !__GNUC_PREREQ (2,92)
# define __restrict /* Ignore */
#endif
/* ISO C99 also allows to declare arrays as non-overlapping. The syntax is
array_name[restrict]
GCC 3.1 supports this. */
#if __GNUC_PREREQ (3,1) && !defined __GNUG__
# define __restrict_arr __restrict
#else
# ifdef __GNUC__
# define __restrict_arr /* Not supported in old GCC. */
# else
# if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
# define __restrict_arr restrict
# else
/* Some other non-C99 compiler. */
# define __restrict_arr /* Not supported. */
# endif
# endif
#endif
#endif /* sys/cdefs.h */