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., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, 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.  Also, VA_OPEN and VA_CLOSE are the beginning
  97    and end of a block.  They must appear at the same nesting level,
  98    and any variables declared after VA_OPEN go out of scope at
  99    VA_CLOSE.  Unfortunately, with a K+R compiler, that includes the
 100    argument list.  You can have multiple instances of VA_OPEN/VA_CLOSE
 101    pairs in a single function in case you need to traverse the
 102    argument list more than once.
 103
 104    For ease of writing code which uses GCC extensions but needs to be
 105    portable to other compilers, we provide the GCC_VERSION macro that
 106    simplifies testing __GNUC__ and __GNUC_MINOR__ together, and various
 107    wrappers around __attribute__.  Also, __extension__ will be #defined
 108    to nothing if it doesn't work.  See below.
 109
 110    This header also defines a lot of obsolete macros:
 111    CONST, VOLATILE, SIGNED, PROTO, EXFUN, DEFUN, DEFUN_VOID,
 112    AND, DOTS, NOARGS.  Don't use them.  */
 113
 114 #ifndef _ANSIDECL_H
 115 #define _ANSIDECL_H     1
 116
 117 /* Every source file includes this file,
 118    so they will all get the switch for lint.  */
 119 /* LINTLIBRARY */
 120
 121 /* Using MACRO(x,y) in cpp #if conditionals does not work with some
 122    older preprocessors.  Thus we can't define something like this:
 123
 124 #define HAVE_GCC_VERSION(MAJOR, MINOR) \
 125   (__GNUC__ > (MAJOR) || (__GNUC__ == (MAJOR) && __GNUC_MINOR__ >= (MINOR)))
 126
 127 and then test "#if HAVE_GCC_VERSION(2,7)".
 128
 129 So instead we use the macro below and test it against specific values.  */
 130
 131 /* This macro simplifies testing whether we are using gcc, and if it
 132    is of a particular minimum version. (Both major & minor numbers are
 133    significant.)  This macro will evaluate to 0 if we are not using
 134    gcc at all.  */
 135 #ifndef GCC_VERSION
 136 #define GCC_VERSION (__GNUC__ * 1000 + __GNUC_MINOR__)
 137 #endif /* GCC_VERSION */
 138
 139 #if defined (__STDC__) || defined (_AIX) || (defined (__mips) && defined (_SYSTYPE_SVR4)) || defined(_WIN32) || (defined(__alpha) && defined(__cplusplus))
 140 /* All known AIX compilers implement these things (but don't always
 141    define __STDC__).  The RISC/OS MIPS compiler defines these things
 142    in SVR4 mode, but does not define __STDC__.  */
 143 /* eraxxon@alumni.rice.edu: The Compaq C++ compiler, unlike many other
 144    C++ compilers, does not define __STDC__, though it acts as if this
 145    was so. (Verified versions: 5.7, 6.2, 6.3, 6.5) */
 146
 147 #define ANSI_PROTOTYPES 1
 148 #define PTR             void *
 149 #define PTRCONST        void *const
 150 #define LONG_DOUBLE     long double
 151
 152 /* PARAMS is often defined elsewhere (e.g. by libintl.h), so wrap it in
 153    a #ifndef.  */
 154 #ifndef PARAMS
 155 #define PARAMS(ARGS)            ARGS
 156 #endif
 157
 158 #define VPARAMS(ARGS)           ARGS
 159 #define VA_START(VA_LIST, VAR)  va_start(VA_LIST, VAR)
 160
 161 /* variadic function helper macros */
 162 /* "struct Qdmy" swallows the semicolon after VA_OPEN/VA_FIXEDARG's
 163    use without inhibiting further decls and without declaring an
 164    actual variable.  */
 165 #define VA_OPEN(AP, VAR)        { va_list AP; va_start(AP, VAR); { struct Qdmy
 166 #define VA_CLOSE(AP)            } va_end(AP); }
 167 #define VA_FIXEDARG(AP, T, N)   struct Qdmy
 168
 169 #undef const
 170 #undef volatile
 171 #undef signed
 172
 173 /* inline requires special treatment; it's in C99, and GCC >=2.7 supports
 174    it too, but it's not in C89.  */
 175 #undef inline
 176 #if __STDC_VERSION__ > 199901L
 177 /* it's a keyword */
 178 #else
 179 # if GCC_VERSION >= 2007
 180 #  define inline __inline__   /* __inline__ prevents -pedantic warnings */
 181 # else
 182 #  define inline  /* nothing */
 183 # endif
 184 #endif
 185
 186 /* These are obsolete.  Do not use.  */
 187 #ifndef IN_GCC
 188 #define CONST           const
 189 #define VOLATILE        volatile
 190 #define SIGNED          signed
 191
 192 #define PROTO(type, name, arglist)      type name arglist
 193 #define EXFUN(name, proto)              name proto
 194 #define DEFUN(name, arglist, args)      name(args)
 195 #define DEFUN_VOID(name)                name(void)
 196 #define AND             ,
 197 #define DOTS            , ...
 198 #define NOARGS          void
 199 #endif /* ! IN_GCC */
 200
 201 #else   /* Not ANSI C.  */
 202
 203 #undef  ANSI_PROTOTYPES
 204 #define PTR             char *
 205 #define PTRCONST        PTR
 206 #define LONG_DOUBLE     double
 207
 208 #define PARAMS(args)            ()
 209 #define VPARAMS(args)           (va_alist) va_dcl
 210 #define VA_START(va_list, var)  va_start(va_list)
 211
 212 #define VA_OPEN(AP, VAR)                { va_list AP; va_start(AP); { struct Qdmy
 213 #define VA_CLOSE(AP)                    } va_end(AP); }
 214 #define VA_FIXEDARG(AP, TYPE, NAME)     TYPE NAME = va_arg(AP, TYPE)
 215
 216 /* some systems define these in header files for non-ansi mode */
 217 #undef const
 218 #undef volatile
 219 #undef signed
 220 #undef inline
 221 #define const
 222 #define volatile
 223 #define signed
 224 #define inline
 225
 226 #ifndef IN_GCC
 227 #define CONST
 228 #define VOLATILE
 229 #define SIGNED
 230
 231 #define PROTO(type, name, arglist)      type name ()
 232 #define EXFUN(name, proto)              name()
 233 #define DEFUN(name, arglist, args)      name arglist args;
 234 #define DEFUN_VOID(name)                name()
 235 #define AND             ;
 236 #define DOTS
 237 #define NOARGS
 238 #endif /* ! IN_GCC */
 239
 240 #endif  /* ANSI C.  */
 241
 242 /* Define macros for some gcc attributes.  This permits us to use the
 243    macros freely, and know that they will come into play for the
 244    version of gcc in which they are supported.  */
 245
 246 #if (GCC_VERSION < 2007)
 247 # define __attribute__(x)
 248 #endif
 249
 250 /* Attribute __malloc__ on functions was valid as of gcc 2.96. */
 251 #ifndef ATTRIBUTE_MALLOC
 252 # if (GCC_VERSION >= 2096)
 253 #  define ATTRIBUTE_MALLOC __attribute__ ((__malloc__))
 254 # else
 255 #  define ATTRIBUTE_MALLOC
 256 # endif /* GNUC >= 2.96 */
 257 #endif /* ATTRIBUTE_MALLOC */
 258
 259 /* Attributes on labels were valid as of gcc 2.93. */
 260 #ifndef ATTRIBUTE_UNUSED_LABEL
 261 # if (!defined (__cplusplus) && GCC_VERSION >= 2093)
 262 #  define ATTRIBUTE_UNUSED_LABEL ATTRIBUTE_UNUSED
 263 # else
 264 #  define ATTRIBUTE_UNUSED_LABEL
 265 # endif /* !__cplusplus && GNUC >= 2.93 */
 266 #endif /* ATTRIBUTE_UNUSED_LABEL */
 267
 268 #ifndef ATTRIBUTE_UNUSED
 269 #define ATTRIBUTE_UNUSED __attribute__ ((__unused__))
 270 #endif /* ATTRIBUTE_UNUSED */
 271
 272 /* Before GCC 3.4, the C++ frontend couldn't parse attributes placed after the
 273    identifier name.  */
 274 #if ! defined(__cplusplus) || (GCC_VERSION >= 3004)
 275 # define ARG_UNUSED(NAME) NAME ATTRIBUTE_UNUSED
 276 #else /* !__cplusplus || GNUC >= 3.4 */
 277 # define ARG_UNUSED(NAME) NAME
 278 #endif /* !__cplusplus || GNUC >= 3.4 */
 279
 280 #ifndef ATTRIBUTE_NORETURN
 281 #define ATTRIBUTE_NORETURN __attribute__ ((__noreturn__))
 282 #endif /* ATTRIBUTE_NORETURN */
 283
 284 /* Attribute `nonnull' was valid as of gcc 3.3.  */
 285 #ifndef ATTRIBUTE_NONNULL
 286 # if (GCC_VERSION >= 3003)
 287 #  define ATTRIBUTE_NONNULL(m) __attribute__ ((__nonnull__ (m)))
 288 # else
 289 #  define ATTRIBUTE_NONNULL(m)
 290 # endif /* GNUC >= 3.3 */
 291 #endif /* ATTRIBUTE_NONNULL */
 292
 293 /* Attribute `pure' was valid as of gcc 3.0.  */
 294 #ifndef ATTRIBUTE_PURE
 295 # if (GCC_VERSION >= 3000)
 296 #  define ATTRIBUTE_PURE __attribute__ ((__pure__))
 297 # else
 298 #  define ATTRIBUTE_PURE
 299 # endif /* GNUC >= 3.0 */
 300 #endif /* ATTRIBUTE_PURE */
 301
 302 /* Use ATTRIBUTE_PRINTF when the format specifier must not be NULL.
 303    This was the case for the `printf' format attribute by itself
 304    before GCC 3.3, but as of 3.3 we need to add the `nonnull'
 305    attribute to retain this behavior.  */
 306 #ifndef ATTRIBUTE_PRINTF
 307 #define ATTRIBUTE_PRINTF(m, n) __attribute__ ((__format__ (__printf__, m, n))) ATTRIBUTE_NONNULL(m)
 308 #define ATTRIBUTE_PRINTF_1 ATTRIBUTE_PRINTF(1, 2)
 309 #define ATTRIBUTE_PRINTF_2 ATTRIBUTE_PRINTF(2, 3)
 310 #define ATTRIBUTE_PRINTF_3 ATTRIBUTE_PRINTF(3, 4)
 311 #define ATTRIBUTE_PRINTF_4 ATTRIBUTE_PRINTF(4, 5)
 312 #define ATTRIBUTE_PRINTF_5 ATTRIBUTE_PRINTF(5, 6)
 313 #endif /* ATTRIBUTE_PRINTF */
 314
 315 /* Use ATTRIBUTE_FPTR_PRINTF when the format attribute is to be set on
 316    a function pointer.  Format attributes were allowed on function
 317    pointers as of gcc 3.1.  */
 318 #ifndef ATTRIBUTE_FPTR_PRINTF
 319 # if (GCC_VERSION >= 3001)
 320 #  define ATTRIBUTE_FPTR_PRINTF(m, n) ATTRIBUTE_PRINTF(m, n)
 321 # else
 322 #  define ATTRIBUTE_FPTR_PRINTF(m, n)
 323 # endif /* GNUC >= 3.1 */
 324 # define ATTRIBUTE_FPTR_PRINTF_1 ATTRIBUTE_FPTR_PRINTF(1, 2)
 325 # define ATTRIBUTE_FPTR_PRINTF_2 ATTRIBUTE_FPTR_PRINTF(2, 3)
 326 # define ATTRIBUTE_FPTR_PRINTF_3 ATTRIBUTE_FPTR_PRINTF(3, 4)
 327 # define ATTRIBUTE_FPTR_PRINTF_4 ATTRIBUTE_FPTR_PRINTF(4, 5)
 328 # define ATTRIBUTE_FPTR_PRINTF_5 ATTRIBUTE_FPTR_PRINTF(5, 6)
 329 #endif /* ATTRIBUTE_FPTR_PRINTF */
 330
 331 /* Use ATTRIBUTE_NULL_PRINTF when the format specifier may be NULL.  A
 332    NULL format specifier was allowed as of gcc 3.3.  */
 333 #ifndef ATTRIBUTE_NULL_PRINTF
 334 # if (GCC_VERSION >= 3003)
 335 #  define ATTRIBUTE_NULL_PRINTF(m, n) __attribute__ ((__format__ (__printf__, m, n)))
 336 # else
 337 #  define ATTRIBUTE_NULL_PRINTF(m, n)
 338 # endif /* GNUC >= 3.3 */
 339 # define ATTRIBUTE_NULL_PRINTF_1 ATTRIBUTE_NULL_PRINTF(1, 2)
 340 # define ATTRIBUTE_NULL_PRINTF_2 ATTRIBUTE_NULL_PRINTF(2, 3)
 341 # define ATTRIBUTE_NULL_PRINTF_3 ATTRIBUTE_NULL_PRINTF(3, 4)
 342 # define ATTRIBUTE_NULL_PRINTF_4 ATTRIBUTE_NULL_PRINTF(4, 5)
 343 # define ATTRIBUTE_NULL_PRINTF_5 ATTRIBUTE_NULL_PRINTF(5, 6)
 344 #endif /* ATTRIBUTE_NULL_PRINTF */
 345
 346 /* Attribute `sentinel' was valid as of gcc 3.5.  */
 347 #ifndef ATTRIBUTE_SENTINEL
 348 # if (GCC_VERSION >= 3005)
 349 #  define ATTRIBUTE_SENTINEL __attribute__ ((__sentinel__))
 350 # else
 351 #  define ATTRIBUTE_SENTINEL
 352 # endif /* GNUC >= 3.5 */
 353 #endif /* ATTRIBUTE_SENTINEL */
 354
 355
 356 #ifndef ATTRIBUTE_ALIGNED_ALIGNOF
 357 # if (GCC_VERSION >= 3000)
 358 #  define ATTRIBUTE_ALIGNED_ALIGNOF(m) __attribute__ ((__aligned__ (__alignof__ (m))))
 359 # else
 360 #  define ATTRIBUTE_ALIGNED_ALIGNOF(m)
 361 # endif /* GNUC >= 3.0 */
 362 #endif /* ATTRIBUTE_ALIGNED_ALIGNOF */
 363
 364 /* Useful for structures whose layout must much some binary specification
 365    regardless of the alignment and padding qualities of the compiler.  */
 366 #ifndef ATTRIBUTE_PACKED
 367 # define ATTRIBUTE_PACKED __attribute__ ((packed))
 368 #endif
 369
 370 /* Attribute `hot' and `cold' was valid as of gcc 4.3.  */
 371 #ifndef ATTRIBUTE_COLD
 372 # if (GCC_VERSION >= 4003)
 373 #  define ATTRIBUTE_COLD __attribute__ ((__cold__))
 374 # else
 375 #  define ATTRIBUTE_COLD
 376 # endif /* GNUC >= 4.3 */
 377 #endif /* ATTRIBUTE_COLD */
 378 #ifndef ATTRIBUTE_HOT
 379 # if (GCC_VERSION >= 4003)
 380 #  define ATTRIBUTE_HOT __attribute__ ((__hot__))
 381 # else
 382 #  define ATTRIBUTE_HOT
 383 # endif /* GNUC >= 4.3 */
 384 #endif /* ATTRIBUTE_HOT */
 385
 386 /* We use __extension__ in some places to suppress -pedantic warnings
 387    about GCC extensions.  This feature didn't work properly before
 388    gcc 2.8.  */
 389 #if GCC_VERSION < 2008
 390 #define __extension__
 391 #endif
 392
 393 #endif  /* ansidecl.h   */