glibc/misc/sys/cdefs.h

/* Copyright (C) 1992,93,94,95,96,97,98,99,2000,2001 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


/* 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__))
#else
# define __attribute_used__ __attribute__ ((__unused__))
#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 */