misc/sys/cdefs.h

   1 /* Copyright (C) 1992-2001, 2002 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    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 /* The standard library needs the functions from the ISO C90 standard
  89    in the std namespace.  At the same time we want to be safe for
  90    future changes and we include the ISO C99 code in the non-standard
  91    namespace __c99.  The C++ wrapper header take case of adding the
  92    definitions to the global namespace.  */
  93 #if defined __cplusplus && defined _GLIBCPP_USE_NAMESPACES
  94 # define __BEGIN_NAMESPACE_STD  namespace std {
  95 # define __END_NAMESPACE_STD    }
  96 # define __USING_NAMESPACE_STD(name) using std::name;
  97 # define __BEGIN_NAMESPACE_C99  namespace __c99 {
  98 # define __END_NAMESPACE_C99    }
  99 # define __USING_NAMESPACE_C99(name) using __c99::name;
 100 #else
 101 /* For compatibility we do not add the declarations into any
 102    namespace.  They will end up in the global namespace which is what
 103    old code expects.  */
 104 # define __BEGIN_NAMESPACE_STD
 105 # define __END_NAMESPACE_STD
 106 # define __USING_NAMESPACE_STD(name)
 107 # define __BEGIN_NAMESPACE_C99
 108 # define __END_NAMESPACE_C99
 109 # define __USING_NAMESPACE_C99(name)
 110 #endif
 111
 112
 113 /* Support for bounded pointers.  */
 114 #ifndef __BOUNDED_POINTERS__
 115 # define __bounded      /* nothing */
 116 # define __unbounded    /* nothing */
 117 # define __ptrvalue     /* nothing */
 118 #endif
 119
 120
 121 /* Support for flexible arrays.  */
 122 #if __GNUC_PREREQ (2,97)
 123 /* GCC 2.97 supports C99 flexible array members.  */
 124 # define __flexarr      []
 125 #else
 126 # ifdef __GNUC__
 127 #  define __flexarr     [0]
 128 # else
 129 #  if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
 130 #   define __flexarr    []
 131 #  else
 132 /* Some other non-C99 compiler.  Approximate with [1].  */
 133 #   define __flexarr    [1]
 134 #  endif
 135 # endif
 136 #endif
 137
 138
 139 /* __asm__ ("xyz") is used throughout the headers to rename functions
 140    at the assembly language level.  This is wrapped by the __REDIRECT
 141    macro, in order to support compilers that can do this some other
 142    way.  When compilers don't support asm-names at all, we have to do
 143    preprocessor tricks instead (which don't have exactly the right
 144    semantics, but it's the best we can do).
 145
 146    Example:
 147    int __REDIRECT(setpgrp, (__pid_t pid, __pid_t pgrp), setpgid); */
 148
 149 #if defined __GNUC__ && __GNUC__ >= 2
 150
 151 # define __REDIRECT(name, proto, alias) name proto __asm__ (__ASMNAME (#alias))
 152 # define __ASMNAME(cname)  __ASMNAME2 (__USER_LABEL_PREFIX__, cname)
 153 # define __ASMNAME2(prefix, cname) __STRING (prefix) cname
 154
 155 /*
 156 #elif __SOME_OTHER_COMPILER__
 157
 158 # define __REDIRECT(name, proto, alias) name proto; \
 159         _Pragma("let " #name " = " #alias)
 160 */
 161 #endif
 162
 163 /* GCC has various useful declarations that can be made with the
 164    `__attribute__' syntax.  All of the ways we use this do fine if
 165    they are omitted for compilers that don't understand it. */
 166 #if !defined __GNUC__ || __GNUC__ < 2
 167 # define __attribute__(xyz)     /* Ignore */
 168 #endif
 169
 170 /* At some point during the gcc 2.96 development the `malloc' attribute
 171    for functions was introduced.  We don't want to use it unconditionally
 172    (although this would be possible) since it generates warnings.  */
 173 #if __GNUC_PREREQ (2,96)
 174 # define __attribute_malloc__ __attribute__ ((__malloc__))
 175 #else
 176 # define __attribute_malloc__ /* Ignore */
 177 #endif
 178
 179 /* At some point during the gcc 2.96 development the `pure' attribute
 180    for functions was introduced.  We don't want to use it unconditionally
 181    (although this would be possible) since it generates warnings.  */
 182 #if __GNUC_PREREQ (2,96)
 183 # define __attribute_pure__ __attribute__ ((__pure__))
 184 #else
 185 # define __attribute_pure__ /* Ignore */
 186 #endif
 187
 188 /* At some point during the gcc 3.1 development the `used' attribute
 189    for functions was introduced.  We don't want to use it unconditionally
 190    (although this would be possible) since it generates warnings.  */
 191 #if __GNUC_PREREQ (3,1)
 192 # define __attribute_used__ __attribute__ ((__used__))
 193 # define __attribute_noinline__ __attribute__ ((__noinline__))
 194 #else
 195 # define __attribute_used__ __attribute__ ((__unused__))
 196 # define __attribute_noinline__ /* Ignore */
 197 #endif
 198
 199 /* At some point during the gcc 2.8 development the `format_arg' attribute
 200    for functions was introduced.  We don't want to use it unconditionally
 201    (although this would be possible) since it generates warnings.
 202    If several `format_arg' attributes are given for the same function, in
 203    gcc-3.0 and older, all but the last one are ignored.  In newer gccs,
 204    all designated arguments are considered.  */
 205 #if __GNUC_PREREQ (2,8)
 206 # define __attribute_format_arg__(x) __attribute__ ((__format_arg__ (x)))
 207 #else
 208 # define __attribute_format_arg__(x) /* Ignore */
 209 #endif
 210
 211 /* At some point during the gcc 2.97 development the `strfmon' format
 212    attribute for functions was introduced.  We don't want to use it
 213    unconditionally (although this would be possible) since it
 214    generates warnings.  */
 215 #if __GNUC_PREREQ (2,97)
 216 # define __attribute_format_strfmon__(a,b) \
 217   __attribute__ ((__format__ (__strfmon__, a, b)))
 218 #else
 219 # define __attribute_format_strfmon__(a,b) /* Ignore */
 220 #endif
 221
 222 /* It is possible to compile containing GCC extensions even if GCC is
 223    run in pedantic mode if the uses are carefully marked using the
 224    `__extension__' keyword.  But this is not generally available before
 225    version 2.8.  */
 226 #if !__GNUC_PREREQ (2,8)
 227 # define __extension__          /* Ignore */
 228 #endif
 229
 230 /* __restrict is known in EGCS 1.2 and above. */
 231 #if !__GNUC_PREREQ (2,92)
 232 # define __restrict     /* Ignore */
 233 #endif
 234
 235 /* ISO C99 also allows to declare arrays as non-overlapping.  The syntax is
 236      array_name[restrict]
 237    GCC 3.1 supports this.  */
 238 #if __GNUC_PREREQ (3,1) && !defined __GNUG__
 239 # define __restrict_arr __restrict
 240 #else
 241 # ifdef __GNUC__
 242 #  define __restrict_arr        /* Not supported in old GCC.  */
 243 # else
 244 #  if defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L
 245 #   define __restrict_arr       restrict
 246 #  else
 247 /* Some other non-C99 compiler.  */
 248 #   define __restrict_arr       /* Not supported.  */
 249 #  endif
 250 # endif
 251 #endif
 252
 253 #endif   /* sys/cdefs.h */