clang/lib/Headers/limits.h

   1 /*===---- limits.h - Standard header for integer sizes --------------------===*\
   2  *
   3  * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4  * See https://llvm.org/LICENSE.txt for license information.
   5  * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6  *
   7 \*===----------------------------------------------------------------------===*/
   8
   9 #ifndef __CLANG_LIMITS_H
  10 #define __CLANG_LIMITS_H
  11
  12 /* The system's limits.h may, in turn, try to #include_next GCC's limits.h.
  13    Avert this #include_next madness. */
  14 #if defined __GNUC__ && !defined _GCC_LIMITS_H_
  15 #define _GCC_LIMITS_H_
  16 #endif
  17
  18 /* System headers include a number of constants from POSIX in <limits.h>.
  19    Include it if we're hosted. */
  20 #if __STDC_HOSTED__ && __has_include_next(<limits.h>)
  21 #include_next <limits.h>
  22 #endif
  23
  24 /* Many system headers try to "help us out" by defining these.  No really, we
  25    know how big each datatype is. */
  26 #undef  SCHAR_MIN
  27 #undef  SCHAR_MAX
  28 #undef  UCHAR_MAX
  29 #undef  SHRT_MIN
  30 #undef  SHRT_MAX
  31 #undef  USHRT_MAX
  32 #undef  INT_MIN
  33 #undef  INT_MAX
  34 #undef  UINT_MAX
  35 #undef  LONG_MIN
  36 #undef  LONG_MAX
  37 #undef  ULONG_MAX
  38
  39 #undef  CHAR_BIT
  40 #undef  CHAR_MIN
  41 #undef  CHAR_MAX
  42
  43 /* C90/99 5.2.4.2.1 */
  44 #define SCHAR_MAX __SCHAR_MAX__
  45 #define SHRT_MAX  __SHRT_MAX__
  46 #define INT_MAX   __INT_MAX__
  47 #define LONG_MAX  __LONG_MAX__
  48
  49 #define SCHAR_MIN (-__SCHAR_MAX__-1)
  50 #define SHRT_MIN  (-__SHRT_MAX__ -1)
  51 #define INT_MIN   (-__INT_MAX__  -1)
  52 #define LONG_MIN  (-__LONG_MAX__ -1L)
  53
  54 #define UCHAR_MAX (__SCHAR_MAX__*2  +1)
  55 #if __SHRT_WIDTH__ < __INT_WIDTH__
  56 #define USHRT_MAX (__SHRT_MAX__ * 2 + 1)
  57 #else
  58 #define USHRT_MAX (__SHRT_MAX__ * 2U + 1U)
  59 #endif
  60 #define UINT_MAX  (__INT_MAX__  *2U +1U)
  61 #define ULONG_MAX (__LONG_MAX__ *2UL+1UL)
  62
  63 #ifndef MB_LEN_MAX
  64 #define MB_LEN_MAX 1
  65 #endif
  66
  67 #define CHAR_BIT  __CHAR_BIT__
  68
  69 /* C2x 5.2.4.2.1 */
  70 /* FIXME: This is using the placeholder dates Clang produces for these macros
  71    in C2x mode; switch to the correct values once they've been published. */
  72 #if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202000L
  73 #define BOOL_WIDTH   __BOOL_WIDTH__
  74 #define CHAR_WIDTH   CHAR_BIT
  75 #define SCHAR_WIDTH  CHAR_BIT
  76 #define UCHAR_WIDTH  CHAR_BIT
  77 #define USHRT_WIDTH  __SHRT_WIDTH__
  78 #define SHRT_WIDTH   __SHRT_WIDTH__
  79 #define UINT_WIDTH   __INT_WIDTH__
  80 #define INT_WIDTH    __INT_WIDTH__
  81 #define ULONG_WIDTH  __LONG_WIDTH__
  82 #define LONG_WIDTH   __LONG_WIDTH__
  83 #define ULLONG_WIDTH __LLONG_WIDTH__
  84 #define LLONG_WIDTH  __LLONG_WIDTH__
  85
  86 #define BITINT_MAXWIDTH __BITINT_MAXWIDTH__
  87 #endif
  88
  89 #ifdef __CHAR_UNSIGNED__  /* -funsigned-char */
  90 #define CHAR_MIN 0
  91 #define CHAR_MAX UCHAR_MAX
  92 #else
  93 #define CHAR_MIN SCHAR_MIN
  94 #define CHAR_MAX __SCHAR_MAX__
  95 #endif
  96
  97 /* C99 5.2.4.2.1: Added long long.
  98    C++11 18.3.3.2: same contents as the Standard C Library header <limits.h>.
  99  */
 100 #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) ||              \
 101     (defined(__cplusplus) && __cplusplus >= 201103L)
 102
 103 #undef  LLONG_MIN
 104 #undef  LLONG_MAX
 105 #undef  ULLONG_MAX
 106
 107 #define LLONG_MAX  __LONG_LONG_MAX__
 108 #define LLONG_MIN  (-__LONG_LONG_MAX__-1LL)
 109 #define ULLONG_MAX (__LONG_LONG_MAX__*2ULL+1ULL)
 110 #endif
 111
 112 /* LONG_LONG_MIN/LONG_LONG_MAX/ULONG_LONG_MAX are a GNU extension.  It's too bad
 113    that we don't have something like #pragma poison that could be used to
 114    deprecate a macro - the code should just use LLONG_MAX and friends.
 115  */
 116 #if defined(__GNU_LIBRARY__) ? defined(__USE_GNU) : !defined(__STRICT_ANSI__)
 117
 118 #undef   LONG_LONG_MIN
 119 #undef   LONG_LONG_MAX
 120 #undef   ULONG_LONG_MAX
 121
 122 #define LONG_LONG_MAX  __LONG_LONG_MAX__
 123 #define LONG_LONG_MIN  (-__LONG_LONG_MAX__-1LL)
 124 #define ULONG_LONG_MAX (__LONG_LONG_MAX__*2ULL+1ULL)
 125 #endif
 126
 127 #endif /* __CLANG_LIMITS_H */