include/ansidecl.h

   1 /* ANSI and traditional C compatability macros
   2    Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001
   3    Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6 This program is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2 of the License, or
   9 (at your option) any later version.
  10
  11 This program is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with this program; if not, write to the Free Software
  18 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  19
  20 /* ANSI and traditional C compatibility macros
  21
  22    ANSI C is assumed if __STDC__ is #defined.
  23
  24    Macro                ANSI C definition       Traditional C definition
  25    -----                ---- - ----------       ----------- - ----------
  26    ANSI_PROTOTYPES      1                       not defined
  27    PTR                  `void *'                `char *'
  28    PTRCONST             `void *const'           `char *'
  29    LONG_DOUBLE          `long double'           `double'
  30    const                not defined             `'
  31    volatile             not defined             `'
  32    signed               not defined             `'
  33    VA_START(ap, var)    va_start(ap, var)       va_start(ap)
  34
  35    Note that it is safe to write "void foo();" indicating a function
  36    with no return value, in all K+R compilers we have been able to test.
  37
  38    For declaring functions with prototypes, we also provide these:
  39
  40    PARAMS ((prototype))
  41    -- for functions which take a fixed number of arguments.  Use this
  42    when declaring the function.  When defining the function, write a
  43    K+R style argument list.  For example:
  44
  45         char *strcpy PARAMS ((char *dest, char *source));
  46         ...
  47         char *
  48         strcpy (dest, source)
  49              char *dest;
  50              char *source;
  51         { ... }
  52
  53
  54    VPARAMS ((prototype, ...))
  55    -- for functions which take a variable number of arguments.  Use
  56    PARAMS to declare the function, VPARAMS to define it.  For example:
  57
  58         int printf PARAMS ((const char *format, ...));
  59         ...
  60         int
  61         printf VPARAMS ((const char *format, ...))
  62         {
  63            ...
  64         }
  65
  66    For writing functions which take variable numbers of arguments, we
  67    also provide the VA_OPEN, VA_CLOSE, and VA_FIXEDARG macros.  These
  68    hide the differences between K+R <varargs.h> and C89 <stdarg.h> more
  69    thoroughly than the simple VA_START() macro mentioned above.
  70
  71    VA_OPEN and VA_CLOSE are used *instead of* va_start and va_end.
  72    Immediately after VA_OPEN, put a sequence of VA_FIXEDARG calls
  73    corresponding to the list of fixed arguments.  Then use va_arg
  74    normally to get the variable arguments, or pass your va_list object
  75    around.  You do not declare the va_list yourself; VA_OPEN does it
  76    for you.
  77
  78    Here is a complete example:
  79
  80         int
  81         printf VPARAMS ((const char *format, ...))
  82         {
  83            int result;
  84
  85            VA_OPEN (ap, format);
  86            VA_FIXEDARG (ap, const char *, format);
  87
  88            result = vfprintf (stdout, format, ap);
  89            VA_CLOSE (ap);
  90
  91            return result;
  92         }
  93
  94
  95    You can declare variables either before or after the VA_OPEN,
  96    VA_FIXEDARG sequence.  You can _not_ put statements before VA_OPEN.
  97    Also, VA_OPEN and VA_CLOSE are the beginning and end of a block.
  98    They must appear at the same nesting level, and any variables
  99    declared after VA_OPEN go out of scope at VA_CLOSE.  Unfortunately,
 100    with a K+R compiler, that includes the argument list.
 101
 102    For ease of writing code which uses GCC extensions but needs to be
 103    portable to other compilers, we provide the GCC_VERSION macro that
 104    simplifies testing __GNUC__ and __GNUC_MINOR__ together, and various
 105    wrappers around __attribute__.  Also, __extension__ will be #defined
 106    to nothing if it doesn't work.  See below.
 107
 108    This header also defines a lot of obsolete macros:
 109    CONST, VOLATILE, SIGNED, PROTO, EXFUN, DEFUN, DEFUN_VOID,
 110    AND, DOTS, NOARGS.  Don't use them.  */
 111
 112 #ifndef _ANSIDECL_H
 113 #define _ANSIDECL_H     1
 114
 115 /* Every source file includes this file,
 116    so they will all get the switch for lint.  */
 117 /* LINTLIBRARY */
 118
 119 /* Using MACRO(x,y) in cpp #if conditionals does not work with some
 120    older preprocessors.  Thus we can't define something like this:
 121
 122 #define HAVE_GCC_VERSION(MAJOR, MINOR) \
 123   (__GNUC__ > (MAJOR) || (__GNUC__ == (MAJOR) && __GNUC_MINOR__ >= (MINOR)))
 124
 125 and then test "#if HAVE_GCC_VERSION(2,7)".
 126
 127 So instead we use the macro below and test it against specific values.  */
 128
 129 /* This macro simplifies testing whether we are using gcc, and if it
 130    is of a particular minimum version. (Both major & minor numbers are
 131    significant.)  This macro will evaluate to 0 if we are not using
 132    gcc at all.  */
 133 #ifndef GCC_VERSION
 134 #define GCC_VERSION (__GNUC__ * 1000 + __GNUC_MINOR__)
 135 #endif /* GCC_VERSION */
 136
 137 #if defined (__STDC__) || defined (_AIX) || (defined (__mips) && defined (_SYSTYPE_SVR4)) || defined(_WIN32)
 138 /* All known AIX compilers implement these things (but don't always
 139    define __STDC__).  The RISC/OS MIPS compiler defines these things
 140    in SVR4 mode, but does not define __STDC__.  */
 141
 142 #define ANSI_PROTOTYPES 1
 143 #define PTR             void *
 144 #define PTRCONST        void *const
 145 #define LONG_DOUBLE     long double
 146
 147 #define PARAMS(ARGS)            ARGS
 148 #define VPARAMS(ARGS)           ARGS
 149 #define VA_START(VA_LIST, VAR)  va_start(VA_LIST, VAR)
 150
 151 /* variadic function helper macros */
 152 /* "struct Qdmy" swallows the semicolon after VA_OPEN/VA_FIXEDARG's
 153    use without inhibiting further decls and without declaring an
 154    actual variable.  */
 155 #define VA_OPEN(AP, VAR)        va_list AP; va_start(AP, VAR); { struct Qdmy
 156 #define VA_CLOSE(AP)            } va_end(AP)
 157 #define VA_FIXEDARG(AP, T, N)   struct Qdmy
 158
 159 #undef const
 160 #undef volatile
 161 #undef signed
 162
 163 /* inline requires special treatment; it's in C99, and GCC >=2.7 supports
 164    it too, but it's not in C89.  */
 165 #undef inline
 166 #if __STDC_VERSION__ > 199901L
 167 /* it's a keyword */
 168 #else
 169 # if GCC_VERSION >= 2007
 170 #  define inline __inline__   /* __inline__ prevents -pedantic warnings */
 171 # else
 172 #  define inline  /* nothing */
 173 # endif
 174 #endif
 175
 176 /* These are obsolete.  Do not use.  */
 177 #ifndef IN_GCC
 178 #define CONST           const
 179 #define VOLATILE        volatile
 180 #define SIGNED          signed
 181
 182 #define PROTO(type, name, arglist)      type name arglist
 183 #define EXFUN(name, proto)              name proto
 184 #define DEFUN(name, arglist, args)      name(args)
 185 #define DEFUN_VOID(name)                name(void)
 186 #define AND             ,
 187 #define DOTS            , ...
 188 #define NOARGS          void
 189 #endif /* ! IN_GCC */
 190
 191 #else   /* Not ANSI C.  */
 192
 193 #undef  ANSI_PROTOTYPES
 194 #define PTR             char *
 195 #define PTRCONST        PTR
 196 #define LONG_DOUBLE     double
 197
 198 #define PARAMS(args)            ()
 199 #define VPARAMS(args)           (va_alist) va_dcl
 200 #define VA_START(va_list, var)  va_start(va_list)
 201
 202 #define VA_OPEN(AP, VAR)                va_list AP; va_start(AP); { struct Qdmy
 203 #define VA_CLOSE(AP)                    } va_end(AP)
 204 #define VA_FIXEDARG(AP, TYPE, NAME)     TYPE NAME = va_arg(AP, TYPE)
 205
 206 /* some systems define these in header files for non-ansi mode */
 207 #undef const
 208 #undef volatile
 209 #undef signed
 210 #undef inline
 211 #define const
 212 #define volatile
 213 #define signed
 214 #define inline
 215
 216 #ifndef IN_GCC
 217 #define CONST
 218 #define VOLATILE
 219 #define SIGNED
 220
 221 #define PROTO(type, name, arglist)      type name ()
 222 #define EXFUN(name, proto)              name()
 223 #define DEFUN(name, arglist, args)      name arglist args;
 224 #define DEFUN_VOID(name)                name()
 225 #define AND             ;
 226 #define DOTS
 227 #define NOARGS
 228 #endif /* ! IN_GCC */
 229
 230 #endif  /* ANSI C.  */
 231
 232 /* Define macros for some gcc attributes.  This permits us to use the
 233    macros freely, and know that they will come into play for the
 234    version of gcc in which they are supported.  */
 235
 236 #if (GCC_VERSION < 2007)
 237 # define __attribute__(x)
 238 #endif
 239
 240 /* Attribute __malloc__ on functions was valid as of gcc 2.96. */
 241 #ifndef ATTRIBUTE_MALLOC
 242 # if (GCC_VERSION >= 2096)
 243 #  define ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
 244 # else
 245 #  define ATTRIBUTE_MALLOC
 246 # endif /* GNUC >= 2.96 */
 247 #endif /* ATTRIBUTE_MALLOC */
 248
 249 /* Attributes on labels were valid as of gcc 2.93. */
 250 #ifndef ATTRIBUTE_UNUSED_LABEL
 251 # if (GCC_VERSION >= 2093)
 252 #  define ATTRIBUTE_UNUSED_LABEL ATTRIBUTE_UNUSED
 253 # else
 254 #  define ATTRIBUTE_UNUSED_LABEL
 255 # endif /* GNUC >= 2.93 */
 256 #endif /* ATTRIBUTE_UNUSED_LABEL */
 257
 258 #ifndef ATTRIBUTE_UNUSED
 259 #define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
 260 #endif /* ATTRIBUTE_UNUSED */
 261
 262 #ifndef ATTRIBUTE_NORETURN
 263 #define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
 264 #endif /* ATTRIBUTE_NORETURN */
 265
 266 #ifndef ATTRIBUTE_PRINTF
 267 #define ATTRIBUTE_PRINTF(m, n) __attribute__ ((__format__ (__printf__, m, n)))
 268 #define ATTRIBUTE_PRINTF_1 ATTRIBUTE_PRINTF(1, 2)
 269 #define ATTRIBUTE_PRINTF_2 ATTRIBUTE_PRINTF(2, 3)
 270 #define ATTRIBUTE_PRINTF_3 ATTRIBUTE_PRINTF(3, 4)
 271 #define ATTRIBUTE_PRINTF_4 ATTRIBUTE_PRINTF(4, 5)
 272 #define ATTRIBUTE_PRINTF_5 ATTRIBUTE_PRINTF(5, 6)
 273 #endif /* ATTRIBUTE_PRINTF */
 274
 275 /* We use __extension__ in some places to suppress -pedantic warnings
 276    about GCC extensions.  This feature didn't work properly before
 277    gcc 2.8.  */
 278 #if GCC_VERSION < 2008
 279 #define __extension__
 280 #endif
 281
 282 /* Bootstrap support:  Adjust certain macros defined by Autoconf,
 283    which are only valid for the stage1 compiler.  If we detect
 284    a modern version of GCC, we are probably in stage2 or beyond,
 285    so unconditionally reset the values.  Note that const, inline,
 286    etc. have been dealt with above.  */
 287 #if (GCC_VERSION >= 2007)
 288 # ifndef HAVE_LONG_DOUBLE
 289 #  define HAVE_LONG_DOUBLE 1
 290 # endif
 291 #endif /* GCC >= 2.7 */
 292
 293 #endif  /* ansidecl.h   */