clang/lib/Headers/stddef.h

   1 /*===---- stddef.h - Basic type definitions --------------------------------===
   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
  10 #if !defined(__STDDEF_H) || defined(__need_ptrdiff_t) ||                       \
  11     defined(__need_size_t) || defined(__need_wchar_t) ||                       \
  12     defined(__need_NULL) || defined(__need_wint_t)
  13
  14 #if !defined(__need_ptrdiff_t) && !defined(__need_size_t) &&                   \
  15     !defined(__need_wchar_t) && !defined(__need_NULL) &&                       \
  16     !defined(__need_wint_t)
  17 /* Always define miscellaneous pieces when modules are available. */
  18 #if !__has_feature(modules)
  19 #define __STDDEF_H
  20 #endif
  21 #define __need_ptrdiff_t
  22 #define __need_size_t
  23 #define __need_wchar_t
  24 #define __need_NULL
  25 #define __need_STDDEF_H_misc
  26 /* __need_wint_t is intentionally not defined here. */
  27 #endif
  28
  29 #if defined(__need_ptrdiff_t)
  30 #if !defined(_PTRDIFF_T) || __has_feature(modules)
  31 /* Always define ptrdiff_t when modules are available. */
  32 #if !__has_feature(modules)
  33 #define _PTRDIFF_T
  34 #endif
  35 typedef __PTRDIFF_TYPE__ ptrdiff_t;
  36 #endif
  37 #undef __need_ptrdiff_t
  38 #endif /* defined(__need_ptrdiff_t) */
  39
  40 #if defined(__need_size_t)
  41 #if !defined(_SIZE_T) || __has_feature(modules)
  42 /* Always define size_t when modules are available. */
  43 #if !__has_feature(modules)
  44 #define _SIZE_T
  45 #endif
  46 typedef __SIZE_TYPE__ size_t;
  47 #endif
  48 #undef __need_size_t
  49 #endif /*defined(__need_size_t) */
  50
  51 #if defined(__need_STDDEF_H_misc)
  52 /* ISO9899:2011 7.20 (C11 Annex K): Define rsize_t if __STDC_WANT_LIB_EXT1__ is
  53  * enabled. */
  54 #if (defined(__STDC_WANT_LIB_EXT1__) && __STDC_WANT_LIB_EXT1__ >= 1 && \
  55      !defined(_RSIZE_T)) || __has_feature(modules)
  56 /* Always define rsize_t when modules are available. */
  57 #if !__has_feature(modules)
  58 #define _RSIZE_T
  59 #endif
  60 typedef __SIZE_TYPE__ rsize_t;
  61 #endif
  62 #endif /* defined(__need_STDDEF_H_misc) */
  63
  64 #if defined(__need_wchar_t)
  65 #if !defined(__cplusplus) || (defined(_MSC_VER) && !_NATIVE_WCHAR_T_DEFINED)
  66 /* Always define wchar_t when modules are available. */
  67 #if !defined(_WCHAR_T) || __has_feature(modules)
  68 #if !__has_feature(modules)
  69 #define _WCHAR_T
  70 #if defined(_MSC_EXTENSIONS)
  71 #define _WCHAR_T_DEFINED
  72 #endif
  73 #endif
  74 typedef __WCHAR_TYPE__ wchar_t;
  75 #endif
  76 #endif
  77 #undef __need_wchar_t
  78 #endif /* defined(__need_wchar_t) */
  79
  80 #if defined(__need_NULL)
  81 #undef NULL
  82 #ifdef __cplusplus
  83 #  if !defined(__MINGW32__) && !defined(_MSC_VER)
  84 #    define NULL __null
  85 #  else
  86 #    define NULL 0
  87 #  endif
  88 #else
  89 #  define NULL ((void*)0)
  90 #endif
  91 #ifdef __cplusplus
  92 #if defined(_MSC_EXTENSIONS) && defined(_NATIVE_NULLPTR_SUPPORTED)
  93 namespace std { typedef decltype(nullptr) nullptr_t; }
  94 using ::std::nullptr_t;
  95 #endif
  96 #endif
  97 #undef __need_NULL
  98 #endif /* defined(__need_NULL) */
  99
 100 /* FIXME: This is using the placeholder dates Clang produces for these macros
 101    in C2x mode; switch to the correct values once they've been published. */
 102 #if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202000L
 103 typedef typeof(nullptr) nullptr_t;
 104 #endif /* defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202000L */
 105
 106 #if defined(__need_STDDEF_H_misc) && defined(__STDC_VERSION__) &&              \
 107     __STDC_VERSION__ >= 202000L
 108 #define unreachable() __builtin_unreachable()
 109 #endif /* defined(__need_STDDEF_H_misc) && >= C23 */
 110
 111 #if defined(__need_STDDEF_H_misc)
 112 #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) ||              \
 113     (defined(__cplusplus) && __cplusplus >= 201103L)
 114 #include "__stddef_max_align_t.h"
 115 #endif
 116 #define offsetof(t, d) __builtin_offsetof(t, d)
 117 #undef __need_STDDEF_H_misc
 118 #endif  /* defined(__need_STDDEF_H_misc) */
 119
 120 /* Some C libraries expect to see a wint_t here. Others (notably MinGW) will use
 121 __WINT_TYPE__ directly; accommodate both by requiring __need_wint_t */
 122 #if defined(__need_wint_t)
 123 /* Always define wint_t when modules are available. */
 124 #if !defined(_WINT_T) || __has_feature(modules)
 125 #if !__has_feature(modules)
 126 #define _WINT_T
 127 #endif
 128 typedef __WINT_TYPE__ wint_t;
 129 #endif
 130 #undef __need_wint_t
 131 #endif /* __need_wint_t */
 132
 133 #endif