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 /* 11 * This header is designed to be included multiple times. If any of the __need_ 12 * macros are defined, then only that subset of interfaces are provided. This 13 * can be useful for POSIX headers that need to not expose all of stddef.h, but 14 * need to use some of its interfaces. Otherwise this header provides all of 15 * the expected interfaces. 16 * 17 * When clang modules are enabled, this header is a textual header. It ignores 18 * its header guard so that multiple submodules can export its interfaces. 19 * Take module SM with submodules A and B, whose headers both include stddef.h 20 * When SM.A builds, __STDDEF_H will be defined. When SM.B builds, the 21 * definition from SM.A will leak when building without local submodule 22 * visibility. stddef.h wouldn't include any of its implementation headers, and 23 * SM.B wouldn't import any of the stddef modules, and SM.B's `export *` 24 * wouldn't export any stddef interfaces as expected. However, since stddef.h 25 * ignores its header guard when building with modules, it all works as 26 * expected. 27 * 28 * When clang modules are not enabled, the header guards can function in the 29 * normal simple fashion. 30 */ 31 #if !defined(__STDDEF_H) || __has_feature(modules) || \ 32 (defined(__STDC_WANT_LIB_EXT1__) && __STDC_WANT_LIB_EXT1__ >= 1) || \ 33 defined(__need_ptrdiff_t) || defined(__need_size_t) || \ 34 defined(__need_rsize_t) || defined(__need_wchar_t) || \ 35 defined(__need_NULL) || defined(__need_nullptr_t) || \ 36 defined(__need_unreachable) || defined(__need_max_align_t) || \ 37 defined(__need_offsetof) || defined(__need_wint_t) 38 39 #if !defined(__need_ptrdiff_t) && !defined(__need_size_t) && \ 40 !defined(__need_rsize_t) && !defined(__need_wchar_t) && \ 41 !defined(__need_NULL) && !defined(__need_nullptr_t) && \ 42 !defined(__need_unreachable) && !defined(__need_max_align_t) && \ 43 !defined(__need_offsetof) && !defined(__need_wint_t) 44 #define __STDDEF_H 45 #define __need_ptrdiff_t 46 #define __need_size_t 47 /* ISO9899:2011 7.20 (C11 Annex K): Define rsize_t if __STDC_WANT_LIB_EXT1__ is 48 * enabled. */ 49 #if defined(__STDC_WANT_LIB_EXT1__) && __STDC_WANT_LIB_EXT1__ >= 1 50 #define __need_rsize_t 51 #endif 52 #define __need_wchar_t 53 #define __need_NULL 54 #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L) || \ 55 defined(__cplusplus) 56 #define __need_nullptr_t 57 #endif 58 #if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L 59 #define __need_unreachable 60 #endif 61 #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) || \ 62 (defined(__cplusplus) && __cplusplus >= 201103L) 63 #define __need_max_align_t 64 #endif 65 #define __need_offsetof 66 /* wint_t is provided by <wchar.h> and not <stddef.h>. It's here 67 * for compatibility, but must be explicitly requested. Therefore 68 * __need_wint_t is intentionally not defined here. */ 69 #endif 70 71 #if defined(__need_ptrdiff_t) 72 #include <__stddef_ptrdiff_t.h> 73 #undef __need_ptrdiff_t 74 #endif /* defined(__need_ptrdiff_t) */ 75 76 #if defined(__need_size_t) 77 #include <__stddef_size_t.h> 78 #undef __need_size_t 79 #endif /*defined(__need_size_t) */ 80 81 #if defined(__need_rsize_t) 82 #include <__stddef_rsize_t.h> 83 #undef __need_rsize_t 84 #endif /* defined(__need_rsize_t) */ 85 86 #if defined(__need_wchar_t) 87 #include <__stddef_wchar_t.h> 88 #undef __need_wchar_t 89 #endif /* defined(__need_wchar_t) */ 90 91 #if defined(__need_NULL) 92 #include <__stddef_null.h> 93 #undef __need_NULL 94 #endif /* defined(__need_NULL) */ 95 96 #if defined(__need_nullptr_t) 97 #include <__stddef_nullptr_t.h> 98 #undef __need_nullptr_t 99 #endif /* defined(__need_nullptr_t) */ 100 101 #if defined(__need_unreachable) 102 #include <__stddef_unreachable.h> 103 #undef __need_unreachable 104 #endif /* defined(__need_unreachable) */ 105 106 #if defined(__need_max_align_t) 107 #include <__stddef_max_align_t.h> 108 #undef __need_max_align_t 109 #endif /* defined(__need_max_align_t) */ 110 111 #if defined(__need_offsetof) 112 #include <__stddef_offsetof.h> 113 #undef __need_offsetof 114 #endif /* defined(__need_offsetof) */ 115 116 /* Some C libraries expect to see a wint_t here. Others (notably MinGW) will use 117 __WINT_TYPE__ directly; accommodate both by requiring __need_wint_t */ 118 #if defined(__need_wint_t) 119 #include <__stddef_wint_t.h> 120 #undef __need_wint_t 121 #endif /* __need_wint_t */ 122 123 #endif 124