misc/sys/cdefs.h

   1 /* Copyright (C) 1992,93,94,95,96,97,98,99, 2000 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #ifndef _SYS_CDEFS_H
  20 #define _SYS_CDEFS_H    1
  21
  22 /* We are almost always included from features.h. */
  23 #ifndef _FEATURES_H
  24 # include <features.h>
  25 #endif
  26
  27 /* The GNU libc does not support any K&R compilers or the traditional mode
  28    of ISO C compilers anymore.  Check for some of the combinations not
  29    anymore supported.  */
  30 #if defined __GNUC__ && !defined __STDC__
  31 # error "You need a ISO C conforming compiler to use the glibc headers"
  32 #endif
  33
  34 /* Some user header file might have defined this before.  */
  35 #undef  __P
  36 #undef  __PMT
  37
  38 #ifdef __GNUC__
  39
  40 /* GCC can always grok prototypes.  For C++ programs we add throw()
  41    to help it optimize the function calls.  But this works only with
  42    gcc 2.8.x and egcs.  */
  43 # if defined __cplusplus && __GNUC_PREREQ (2,8)
  44 #  define __THROW       throw ()
  45 # else
  46 #  define __THROW
  47 # endif
  48 # define __P(args)      args __THROW
  49 /* This macro will be used for functions which might take C++ callback
  50    functions.  */
  51 # define __PMT(args)    args
  52
  53 #else   /* Not GCC.  */
  54
  55 # define __inline               /* No inline functions.  */
  56
  57 # define __THROW
  58 # define __P(args)      args
  59 # define __PMT(args)    args
  60
  61 # define __const        const
  62 # define __signed       signed
  63 # define __volatile     volatile
  64
  65 #endif  /* GCC.  */
  66
  67 /* For these things, GCC behaves the ANSI way normally,
  68    and the non-ANSI way under -traditional.  */
  69
  70 #define __CONCAT(x,y)   x ## y
  71 #define __STRING(x)     #x
  72
  73 /* This is not a typedef so `const __ptr_t' does the right thing.  */
  74 #define __ptr_t void *
  75 #define __long_double_t  long double
  76
  77
  78 /* C++ needs to know that types and declarations are C, not C++.  */
  79 #ifdef  __cplusplus
  80 # define __BEGIN_DECLS  extern "C" {
  81 # define __END_DECLS    }
  82 #else
  83 # define __BEGIN_DECLS
  84 # define __END_DECLS
  85 #endif
  86
  87
  88 /* Support for bounded pointers.  */
  89 #ifndef __BOUNDED_POINTERS__
  90 # define __bounded      /* nothing */
  91 # define __unbounded    /* nothing */
  92 # define __ptrvalue     /* nothing */
  93 #endif
  94
  95
  96 /* Support for flexible arrays.  */
  97 #if __GNUC_PREREQ (2,97)
  98 /* GCC 2.97 supports C99 flexible array members.  */
  99 # define __flexarr      []
 100 #else
 101 # ifdef __GNUC__
 102 #  define __flexarr     [0]
 103 # else
 104 #  if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
 105 #   define __flexarr    []
 106 #  else
 107 /* Some other non-C99 compiler.  Approximate with [1].  */
 108 #   define __flexarr    [1]
 109 #  endif
 110 # endif
 111 #endif
 112
 113
 114 /* __asm__ ("xyz") is used throughout the headers to rename functions
 115    at the assembly language level.  This is wrapped by the __REDIRECT
 116    macro, in order to support compilers that can do this some other
 117    way.  When compilers don't support asm-names at all, we have to do
 118    preprocessor tricks instead (which don't have exactly the right
 119    semantics, but it's the best we can do).
 120
 121    Example:
 122    int __REDIRECT(setpgrp, (__pid_t pid, __pid_t pgrp), setpgid); */
 123
 124 #if defined __GNUC__ && __GNUC__ >= 2
 125
 126 # define __REDIRECT(name, proto, alias) name proto __asm__ (__ASMNAME (#alias))
 127 # define __ASMNAME(cname)  __ASMNAME2 (__USER_LABEL_PREFIX__, cname)
 128 # define __ASMNAME2(prefix, cname) __STRING (prefix) cname
 129
 130 /*
 131 #elif __SOME_OTHER_COMPILER__
 132
 133 # define __REDIRECT(name, proto, alias) name proto; \
 134         _Pragma("let " #name " = " #alias)
 135 */
 136 #endif
 137
 138 /* GCC has various useful declarations that can be made with the
 139    `__attribute__' syntax.  All of the ways we use this do fine if
 140    they are omitted for compilers that don't understand it. */
 141 #if !defined __GNUC__ || __GNUC__ < 2
 142 # define __attribute__(xyz)     /* Ignore */
 143 #endif
 144
 145 /* At some point during the gcc 2.96 development the `malloc' attribute
 146    for functions was introduced.  We don't want to use it unconditionally
 147    (although this would be possible) since it generates warnings.  */
 148 #if __GNUC_PREREQ (2,96)
 149 # define __attribute_malloc__ __attribute__ ((__malloc__))
 150 #else
 151 # define __attribute_malloc__ /* Ignore */
 152 #endif
 153
 154 /* At some point during the gcc 2.96 development the `pure' attribute
 155    for functions was introduced.  We don't want to use it unconditionally
 156    (although this would be possible) since it generates warnings.  */
 157 #if __GNUC_PREREQ (2,96)
 158 # define __attribute_pure__ __attribute__ ((__pure__))
 159 #else
 160 # define __attribute_pure__ /* Ignore */
 161 #endif
 162
 163 /* At some point during the gcc 2.8 development the `format_arg' attribute
 164    for functions was introduced.  We don't want to use it unconditionally
 165    (although this would be possible) since it generates warnings.  */
 166 #if __GNUC_PREREQ (2,8)
 167 # define __attribute_format_arg__(x) __attribute__ ((__format_arg__ (x)))
 168 #else
 169 # define __attribute_format_arg__(x) /* Ignore */
 170 #endif
 171
 172 /* It is possible to compile containing GCC extensions even if GCC is
 173    run in pedantic mode if the uses are carefully marked using the
 174    `__extension__' keyword.  But this is not generally available before
 175    version 2.8.  */
 176 #if !__GNUC_PREREQ (2,8)
 177 # define __extension__          /* Ignore */
 178 #endif
 179
 180 /* __restrict is known in EGCS 1.2 and above. */
 181 #if !__GNUC_PREREQ (2,92)
 182 # define __restrict     /* Ignore */
 183 #endif
 184
 185 /* ISO C99 also allows to declare arrays as non-overlapping.  The syntax is
 186      array_name[restrict]
 187    But gcc so far does not support this syntax.  We define a separate macro
 188    for this which can be enabled if the underlying compiler supports it.  */
 189 #define __restrict_arr
 190
 191 #endif   /* sys/cdefs.h */