clang/lib/Headers/stddef.h

/*===---- stddef.h - Basic type definitions --------------------------------===
 *
 * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 * See https://llvm.org/LICENSE.txt for license information.
 * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 *
 *===-----------------------------------------------------------------------===
 */

/*
 * This header is designed to be included multiple times. If any of the __need_
 * macros are defined, then only that subset of interfaces are provided. This
 * can be useful for POSIX headers that need to not expose all of stddef.h, but
 * need to use some of its interfaces. Otherwise this header provides all of
 * the expected interfaces.
 *
 * When clang modules are enabled, this header is a textual header to support
 * the multiple include behavior. As such, it doesn't directly declare anything
 * so that it doesn't add duplicate declarations to all of its includers'
 * modules.
 */
#if defined(__MVS__) && __has_include_next(<stddef.h>)
#undef __need_ptrdiff_t
#undef __need_size_t
#undef __need_rsize_t
#undef __need_wchar_t
#undef __need_NULL
#undef __need_nullptr_t
#undef __need_unreachable
#undef __need_max_align_t
#undef __need_offsetof
#undef __need_wint_t
#include <__stddef_header_macro.h>
#include_next <stddef.h>

#else

#if !defined(__need_ptrdiff_t) && !defined(__need_size_t) &&                   \
    !defined(__need_rsize_t) && !defined(__need_wchar_t) &&                    \
    !defined(__need_NULL) && !defined(__need_nullptr_t) &&                     \
    !defined(__need_unreachable) && !defined(__need_max_align_t) &&            \
    !defined(__need_offsetof) && !defined(__need_wint_t)
#define __need_ptrdiff_t
#define __need_size_t
/* ISO9899:2011 7.20 (C11 Annex K): Define rsize_t if __STDC_WANT_LIB_EXT1__ is
 * enabled. */
#if defined(__STDC_WANT_LIB_EXT1__) && __STDC_WANT_LIB_EXT1__ >= 1
#define __need_rsize_t
#endif
#define __need_wchar_t
#if !defined(__STDDEF_H) || __has_feature(modules)
/*
 * __stddef_null.h is special when building without modules: if __need_NULL is
 * set, then it will unconditionally redefine NULL. To avoid stepping on client
 * definitions of NULL, __need_NULL should only be set the first time this
 * header is included, that is when __STDDEF_H is not defined. However, when
 * building with modules, this header is a textual header and needs to
 * unconditionally include __stdef_null.h to support multiple submodules
 * exporting _Builtin_stddef.null. Take module SM with submodules A and B, whose
 * headers both include stddef.h When SM.A builds, __STDDEF_H will be defined.
 * When SM.B builds, the definition from SM.A will leak when building without
 * local submodule visibility. stddef.h wouldn't include __stddef_null.h, and
 * SM.B wouldn't import _Builtin_stddef.null, and SM.B's `export *` wouldn't
 * export NULL as expected. When building with modules, always include
 * __stddef_null.h so that everything works as expected.
 */
#define __need_NULL
#endif
#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L) ||              \
    defined(__cplusplus)
#define __need_nullptr_t
#endif
#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L
#define __need_unreachable
#endif
#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) ||              \
    (defined(__cplusplus) && __cplusplus >= 201103L)
#define __need_max_align_t
#endif
#define __need_offsetof
/* wint_t is provided by <wchar.h> and not <stddef.h>. It's here
 * for compatibility, but must be explicitly requested. Therefore
 * __need_wint_t is intentionally not defined here. */
#include <__stddef_header_macro.h>
#endif

#if defined(__need_ptrdiff_t)
#include <__stddef_ptrdiff_t.h>
#undef __need_ptrdiff_t
#endif /* defined(__need_ptrdiff_t) */

#if defined(__need_size_t)
#include <__stddef_size_t.h>
#undef __need_size_t
#endif /*defined(__need_size_t) */

#if defined(__need_rsize_t)
#include <__stddef_rsize_t.h>
#undef __need_rsize_t
#endif /* defined(__need_rsize_t) */

#if defined(__need_wchar_t)
#include <__stddef_wchar_t.h>
#undef __need_wchar_t
#endif /* defined(__need_wchar_t) */

#if defined(__need_NULL)
#include <__stddef_null.h>
#undef __need_NULL
#endif /* defined(__need_NULL) */

#if defined(__need_nullptr_t)
#include <__stddef_nullptr_t.h>
#undef __need_nullptr_t
#endif /* defined(__need_nullptr_t) */

#if defined(__need_unreachable)
#include <__stddef_unreachable.h>
#undef __need_unreachable
#endif /* defined(__need_unreachable) */

#if defined(__need_max_align_t)
#include <__stddef_max_align_t.h>
#undef __need_max_align_t
#endif /* defined(__need_max_align_t) */

#if defined(__need_offsetof)
#include <__stddef_offsetof.h>
#undef __need_offsetof
#endif /* defined(__need_offsetof) */

/* Some C libraries expect to see a wint_t here. Others (notably MinGW) will use
__WINT_TYPE__ directly; accommodate both by requiring __need_wint_t */
#if defined(__need_wint_t)
#include <__stddef_wint_t.h>
#undef __need_wint_t
#endif /* __need_wint_t */

#endif /* __MVS__ */