include/sys/cdefs.h

   1 /*      $NetBSD: cdefs.h,v 1.81 2010/12/25 22:30:52 joerg Exp $ */
   2
   3 /*
   4  * Copyright (c) 1991, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Berkeley Software Design, Inc.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      @(#)cdefs.h     8.8 (Berkeley) 1/9/95
  35  */
  36
  37 #ifndef _SYS_CDEFS_H_
  38 #define _SYS_CDEFS_H_
  39
  40 /*
  41  * Macro to test if we're using a GNU C compiler of a specific vintage
  42  * or later, for e.g. features that appeared in a particular version
  43  * of GNU C.  Usage:
  44  *
  45  *      #if __GNUC_PREREQ__(major, minor)
  46  *      ...cool feature...
  47  *      #else
  48  *      ...delete feature...
  49  *      #endif
  50  */
  51 #ifdef __GNUC__
  52 #define __GNUC_PREREQ__(x, y)                                           \
  53         ((__GNUC__ == (x) && __GNUC_MINOR__ >= (y)) ||                  \
  54          (__GNUC__ > (x)))
  55 #else
  56 #define __GNUC_PREREQ__(x, y)   0
  57 #endif
  58
  59 #include <machine/cdefs.h>
  60 #ifdef __ELF__
  61 #include <sys/cdefs_elf.h>
  62 #else
  63 #include <sys/cdefs_aout.h>
  64 #endif
  65
  66 /*
  67  * The __CONCAT macro is used to concatenate parts of symbol names, e.g.
  68  * with "#define OLD(foo) __CONCAT(old,foo)", OLD(foo) produces oldfoo.
  69  * The __CONCAT macro is a bit tricky -- make sure you don't put spaces
  70  * in between its arguments.  __CONCAT can also concatenate double-quoted
  71  * strings produced by the __STRING macro, but this only works with ANSI C.
  72  */
  73
  74 #define ___STRING(x)    __STRING(x)
  75 #define ___CONCAT(x,y)  __CONCAT(x,y)
  76
  77 #if __STDC__ || defined(__cplusplus)
  78 #define __P(protos)     protos          /* full-blown ANSI C */
  79 #define __CONCAT(x,y)   x ## y
  80 #define __STRING(x)     #x
  81
  82 #define __const         const           /* define reserved names to standard */
  83 #define __signed        signed
  84 #define __volatile      volatile
  85 #if defined(__cplusplus) || defined(__PCC__)
  86 #define __inline        inline          /* convert to C++/C99 keyword */
  87 #else
  88 #if !defined(__GNUC__) && !defined(__lint__)
  89 #define __inline                        /* delete GCC keyword */
  90 #endif /* !__GNUC__  && !__lint__ */
  91 #endif /* !__cplusplus */
  92
  93 #else   /* !(__STDC__ || __cplusplus) */
  94 #define __P(protos)     ()              /* traditional C preprocessor */
  95 #define __CONCAT(x,y)   x/**/y
  96 #define __STRING(x)     "x"
  97
  98 #ifndef __GNUC__
  99 #define __const                         /* delete pseudo-ANSI C keywords */
 100 #define __inline
 101 #define __signed
 102 #define __volatile
 103 #endif  /* !__GNUC__ */
 104
 105 /*
 106  * In non-ANSI C environments, new programs will want ANSI-only C keywords
 107  * deleted from the program and old programs will want them left alone.
 108  * Programs using the ANSI C keywords const, inline etc. as normal
 109  * identifiers should define -DNO_ANSI_KEYWORDS.
 110  */
 111 #ifndef NO_ANSI_KEYWORDS
 112 #define const           __const         /* convert ANSI C keywords */
 113 #define inline          __inline
 114 #define signed          __signed
 115 #define volatile        __volatile
 116 #endif /* !NO_ANSI_KEYWORDS */
 117 #endif  /* !(__STDC__ || __cplusplus) */
 118
 119 /*
 120  * Used for internal auditing of the NetBSD source tree.
 121  */
 122 #ifdef __AUDIT__
 123 #define __aconst        __const
 124 #else
 125 #define __aconst
 126 #endif
 127
 128 /*
 129  * The following macro is used to remove const cast-away warnings
 130  * from gcc -Wcast-qual; it should be used with caution because it
 131  * can hide valid errors; in particular most valid uses are in
 132  * situations where the API requires it, not to cast away string
 133  * constants. We don't use *intptr_t on purpose here and we are
 134  * explicit about unsigned long so that we don't have additional
 135  * dependencies.
 136  */
 137 #define __UNCONST(a)    ((void *)(unsigned long)(const void *)(a))
 138
 139 /*
 140  * The following macro is used to remove the volatile cast-away warnings
 141  * from gcc -Wcast-qual; as above it should be used with caution
 142  * because it can hide valid errors or warnings.  Valid uses include
 143  * making it possible to pass a volatile pointer to memset().
 144  * For the same reasons as above, we use unsigned long and not intptr_t.
 145  */
 146 #define __UNVOLATILE(a) ((void *)(unsigned long)(volatile void *)(a))
 147
 148 /*
 149  * GCC2 provides __extension__ to suppress warnings for various GNU C
 150  * language extensions under "-ansi -pedantic".
 151  */
 152 #if !__GNUC_PREREQ__(2, 0)
 153 #define __extension__           /* delete __extension__ if non-gcc or gcc1 */
 154 #endif
 155
 156 /*
 157  * GCC1 and some versions of GCC2 declare dead (non-returning) and
 158  * pure (no side effects) functions using "volatile" and "const";
 159  * unfortunately, these then cause warnings under "-ansi -pedantic".
 160  * GCC2 uses a new, peculiar __attribute__((attrs)) style.  All of
 161  * these work for GNU C++ (modulo a slight glitch in the C++ grammar
 162  * in the distribution version of 2.5.5).
 163  *
 164  * GCC defines a pure function as depending only on its arguments and
 165  * global variables.  Typical examples are strlen and sqrt.
 166  *
 167  * GCC defines a const function as depending only on its arguments.
 168  * Therefore calling a const function again with identical arguments
 169  * will always produce the same result.
 170  *
 171  * Rounding modes for floating point operations are considered global
 172  * variables and prevent sqrt from being a const function.
 173  *
 174  * Calls to const functions can be optimised away and moved around
 175  * without limitations.
 176  */
 177 #if !__GNUC_PREREQ__(2, 0)
 178 #define __attribute__(x)
 179 #endif
 180
 181 #if __GNUC_PREREQ__(2, 5)
 182 #define __dead          __attribute__((__noreturn__))
 183 #elif defined(__GNUC__)
 184 #define __dead          __volatile
 185 #else
 186 #define __dead
 187 #endif
 188
 189 #if __GNUC_PREREQ__(2, 96)
 190 #define __pure          __attribute__((__pure__))
 191 #elif defined(__GNUC__)
 192 #define __pure          __const
 193 #else
 194 #define __pure
 195 #endif
 196
 197 #if __GNUC_PREREQ__(2, 5)
 198 #define __constfunc     __attribute__((__const__))
 199 #else
 200 #define __constfunc
 201 #endif
 202
 203 #if __GNUC_PREREQ__(3, 0)
 204 #define __noinline      __attribute__((__noinline__))
 205 #else
 206 #define __noinline      /* nothing */
 207 #endif
 208
 209 #if __GNUC_PREREQ__(2, 7)
 210 #define __unused        __attribute__((__unused__))
 211 #else
 212 #define __unused        /* delete */
 213 #endif
 214
 215 #if __GNUC_PREREQ__(3, 1)
 216 #define __used          __attribute__((__used__))
 217 #else
 218 #define __used          __unused
 219 #endif
 220
 221 #if defined(__cplusplus)
 222 #define __BEGIN_EXTERN_C        extern "C" {
 223 #define __END_EXTERN_C          }
 224 #define __static_cast(x,y)      static_cast<x>(y)
 225 #else
 226 #define __BEGIN_EXTERN_C
 227 #define __END_EXTERN_C
 228 #define __static_cast(x,y)      (x)y
 229 #endif
 230
 231 #if __GNUC_PREREQ__(4, 0)
 232 #  define __dso_public  __attribute__((__visibility__("default")))
 233 #  define __dso_hidden  __attribute__((__visibility__("hidden")))
 234 #  define __BEGIN_PUBLIC_DECLS  \
 235         _Pragma("GCC visibility push(default)") __BEGIN_EXTERN_C
 236 #  define __END_PUBLIC_DECLS    __END_EXTERN_C _Pragma("GCC visibility pop")
 237 #  define __BEGIN_HIDDEN_DECLS  \
 238         _Pragma("GCC visibility push(hidden)") __BEGIN_EXTERN_C
 239 #  define __END_HIDDEN_DECLS    __END_EXTERN_C _Pragma("GCC visibility pop")
 240 #else
 241 #  define __dso_public
 242 #  define __dso_hidden
 243 #  define __BEGIN_PUBLIC_DECLS  __BEGIN_EXTERN_C
 244 #  define __END_PUBLIC_DECLS    __END_EXTERN_C
 245 #  define __BEGIN_HIDDEN_DECLS  __BEGIN_EXTERN_C
 246 #  define __END_HIDDEN_DECLS    __END_EXTERN_C
 247 #endif
 248
 249 #define __BEGIN_DECLS           __BEGIN_PUBLIC_DECLS
 250 #define __END_DECLS             __END_PUBLIC_DECLS
 251
 252 /*
 253  * Non-static C99 inline functions are optional bodies.  They don't
 254  * create global symbols if not used, but can be replaced if desirable.
 255  * This differs from the behavior of GCC before version 4.3.  The nearest
 256  * equivalent for older GCC is `extern inline'.  For newer GCC, use the
 257  * gnu_inline attribute additionally to get the old behavior.
 258  *
 259  * For C99 compilers other than GCC, the C99 behavior is expected.
 260  */
 261 #if defined(__GNUC__) && defined(__GNUC_STDC_INLINE__)
 262 #define __c99inline     extern __attribute__((__gnu_inline__)) __inline
 263 #elif defined(__GNUC__)
 264 #define __c99inline     extern __inline
 265 #elif defined(__STDC_VERSION__)
 266 #define __c99inline     __inline
 267 #endif
 268
 269 #if defined(__lint__)
 270 #define __packed        __packed
 271 #define __aligned(x)    /* delete */
 272 #define __section(x)    /* delete */
 273 #elif __GNUC_PREREQ__(2, 7)
 274 #define __packed        __attribute__((__packed__))
 275 #define __aligned(x)    __attribute__((__aligned__(x)))
 276 #define __section(x)    __attribute__((__section__(x)))
 277 #elif defined(__PCC__)
 278 #define __packed        _Pragma("packed 1")
 279 #define __aligned(x)    _Pragma("aligned " __STRING(x))
 280 #define __section(x)    _Pragma("section " ## x)
 281 #else
 282 #define __packed        error: no __packed for this compiler
 283 #define __aligned(x)    error: no __aligned for this compiler
 284 #define __section(x)    error: no __section for this compiler
 285 #endif
 286
 287 /*
 288  * C99 defines the restrict type qualifier keyword, which was made available
 289  * in GCC 2.92.
 290  */
 291 #if defined(__lint__)
 292 #define __restrict      /* delete __restrict when not supported */
 293 #elif __STDC_VERSION__ >= 199901L
 294 #define __restrict      restrict
 295 #elif !__GNUC_PREREQ__(2, 92)
 296 #define __restrict      /* delete __restrict when not supported */
 297 #endif
 298
 299 /*
 300  * C99 defines __func__ predefined identifier, which was made available
 301  * in GCC 2.95.
 302  */
 303 #if !(__STDC_VERSION__ >= 199901L)
 304 #if __GNUC_PREREQ__(2, 6)
 305 #define __func__        __PRETTY_FUNCTION__
 306 #elif __GNUC_PREREQ__(2, 4)
 307 #define __func__        __FUNCTION__
 308 #else
 309 #define __func__        ""
 310 #endif
 311 #endif /* !(__STDC_VERSION__ >= 199901L) */
 312
 313 #if defined(_KERNEL)
 314 #if defined(NO_KERNEL_RCSIDS)
 315 #undef __KERNEL_RCSID
 316 #define __KERNEL_RCSID(_n, _s)          /* nothing */
 317 #endif /* NO_KERNEL_RCSIDS */
 318 #endif /* _KERNEL */
 319
 320 #if !defined(_STANDALONE) && !defined(_KERNEL)
 321 #if defined(__GNUC__) || defined(__PCC__)
 322 #define __RENAME(x)     ___RENAME(x)
 323 #else
 324 #ifdef __lint__
 325 #define __RENAME(x)     __symbolrename(x)
 326 #else
 327 #error "No function renaming possible"
 328 #endif /* __lint__ */
 329 #endif /* __GNUC__ */
 330 #else /* _STANDALONE || _KERNEL */
 331 #define __RENAME(x)     no renaming in kernel or standalone environment
 332 #endif
 333
 334 /*
 335  * A barrier to stop the optimizer from moving code or assume live
 336  * register values. This is gcc specific, the version is more or less
 337  * arbitrary, might work with older compilers.
 338  */
 339 #if __GNUC_PREREQ__(2, 95)
 340 #define __insn_barrier()        __asm __volatile("":::"memory")
 341 #else
 342 #define __insn_barrier()        /* */
 343 #endif
 344
 345 /*
 346  * GNU C version 2.96 adds explicit branch prediction so that
 347  * the CPU back-end can hint the processor and also so that
 348  * code blocks can be reordered such that the predicted path
 349  * sees a more linear flow, thus improving cache behavior, etc.
 350  *
 351  * The following two macros provide us with a way to use this
 352  * compiler feature.  Use __predict_true() if you expect the expression
 353  * to evaluate to true, and __predict_false() if you expect the
 354  * expression to evaluate to false.
 355  *
 356  * A few notes about usage:
 357  *
 358  *      * Generally, __predict_false() error condition checks (unless
 359  *        you have some _strong_ reason to do otherwise, in which case
 360  *        document it), and/or __predict_true() `no-error' condition
 361  *        checks, assuming you want to optimize for the no-error case.
 362  *
 363  *      * Other than that, if you don't know the likelihood of a test
 364  *        succeeding from empirical or other `hard' evidence, don't
 365  *        make predictions.
 366  *
 367  *      * These are meant to be used in places that are run `a lot'.
 368  *        It is wasteful to make predictions in code that is run
 369  *        seldomly (e.g. at subsystem initialization time) as the
 370  *        basic block reordering that this affects can often generate
 371  *        larger code.
 372  */
 373 #if __GNUC_PREREQ__(2, 96)
 374 #define __predict_true(exp)     __builtin_expect((exp) != 0, 1)
 375 #define __predict_false(exp)    __builtin_expect((exp) != 0, 0)
 376 #else
 377 #define __predict_true(exp)     (exp)
 378 #define __predict_false(exp)    (exp)
 379 #endif
 380
 381 /*
 382  * Compiler-dependent macros to declare that functions take printf-like
 383  * or scanf-like arguments.  They are null except for versions of gcc
 384  * that are known to support the features properly (old versions of gcc-2
 385  * didn't permit keeping the keywords out of the application namespace).
 386  */
 387 #if __GNUC_PREREQ__(2, 7)
 388 #define __printflike(fmtarg, firstvararg)       \
 389             __attribute__((__format__ (__printf__, fmtarg, firstvararg)))
 390 #define __scanflike(fmtarg, firstvararg)        \
 391             __attribute__((__format__ (__scanf__, fmtarg, firstvararg)))
 392 #define __format_arg(fmtarg)    __attribute__((__format_arg__ (fmtarg)))
 393 #else
 394 #define __printflike(fmtarg, firstvararg)       /* nothing */
 395 #define __scanflike(fmtarg, firstvararg)        /* nothing */
 396 #define __format_arg(fmtarg)                    /* nothing */
 397 #endif
 398
 399 /*
 400  * Macros for manipulating "link sets".  Link sets are arrays of pointers
 401  * to objects, which are gathered up by the linker.
 402  *
 403  * Object format-specific code has provided us with the following macros:
 404  *
 405  *      __link_set_add_text(set, sym)
 406  *              Add a reference to the .text symbol `sym' to `set'.
 407  *
 408  *      __link_set_add_rodata(set, sym)
 409  *              Add a reference to the .rodata symbol `sym' to `set'.
 410  *
 411  *      __link_set_add_data(set, sym)
 412  *              Add a reference to the .data symbol `sym' to `set'.
 413  *
 414  *      __link_set_add_bss(set, sym)
 415  *              Add a reference to the .bss symbol `sym' to `set'.
 416  *
 417  *      __link_set_decl(set, ptype)
 418  *              Provide an extern declaration of the set `set', which
 419  *              contains an array of the pointer type `ptype'.  This
 420  *              macro must be used by any code which wishes to reference
 421  *              the elements of a link set.
 422  *
 423  *      __link_set_start(set)
 424  *              This points to the first slot in the link set.
 425  *
 426  *      __link_set_end(set)
 427  *              This points to the (non-existent) slot after the last
 428  *              entry in the link set.
 429  *
 430  *      __link_set_count(set)
 431  *              Count the number of entries in link set `set'.
 432  *
 433  * In addition, we provide the following macros for accessing link sets:
 434  *
 435  *      __link_set_foreach(pvar, set)
 436  *              Iterate over the link set `set'.  Because a link set is
 437  *              an array of pointers, pvar must be declared as "type **pvar",
 438  *              and the actual entry accessed as "*pvar".
 439  *
 440  *      __link_set_entry(set, idx)
 441  *              Access the link set entry at index `idx' from set `set'.
 442  */
 443 #define __link_set_foreach(pvar, set)                                   \
 444         for (pvar = __link_set_start(set); pvar < __link_set_end(set); pvar++)
 445
 446 #define __link_set_entry(set, idx)      (__link_set_begin(set)[idx])
 447
 448 /*
 449  * Return the number of elements in a statically-allocated array,
 450  * __x.
 451  */
 452 #define __arraycount(__x)       (sizeof(__x) / sizeof(__x[0]))
 453
 454 /* __BIT(n): nth bit, where __BIT(0) == 0x1. */
 455 #define __BIT(__n)      \
 456     (((uintmax_t)(__n) >= NBBY * sizeof(uintmax_t)) ? 0 : ((uintmax_t)1 << (uintmax_t)(__n)))
 457
 458 /* __BITS(m, n): bits m through n, m < n. */
 459 #define __BITS(__m, __n)        \
 460         ((__BIT(MAX((__m), (__n)) + 1) - 1) ^ (__BIT(MIN((__m), (__n))) - 1))
 461
 462 /* find least significant bit that is set */
 463 #define __LOWEST_SET_BIT(__mask) ((((__mask) - 1) & (__mask)) ^ (__mask))
 464
 465 #define __PRIuBIT       PRIuMAX
 466 #define __PRIuBITS      __PRIuBIT
 467
 468 #define __PRIxBIT       PRIxMAX
 469 #define __PRIxBITS      __PRIxBIT
 470
 471 #define __SHIFTOUT(__x, __mask) (((__x) & (__mask)) / __LOWEST_SET_BIT(__mask))
 472 #define __SHIFTIN(__x, __mask) ((__x) * __LOWEST_SET_BIT(__mask))
 473 #define __SHIFTOUT_MASK(__mask) __SHIFTOUT((__mask), (__mask))
 474
 475 /*
 476  * Only to be used in other headers that are included from both c or c++
 477  * NOT to be used in code.
 478  */
 479 #ifdef __cplusplus
 480 #define __CAST(__dt, __st)      static_cast<__dt>(__st)
 481 #else
 482 #define __CAST(__dt, __st)      ((__dt)(__st))
 483 #endif
 484
 485 #ifdef _MINIX
 486 /* If compiling in Minix tree, Minix ANSI definitions are always useful. */
 487 #endif
 488
 489 #endif /* !_SYS_CDEFS_H_ */