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. It ignores
 * its header guard so that multiple submodules can export its interfaces.
 * 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 any of its implementation headers, and
 * SM.B wouldn't import any of the stddef modules, and SM.B's `export *`
 * wouldn't export any stddef interfaces as expected. However, since stddef.h
 * ignores its header guard when building with modules, it all works as
 * expected.
 *
 * When clang modules are not enabled, the header guards can function in the
 * normal simple fashion.
 */
#if !defined(__STDDEF_H) || __has_feature(modules) ||                          \
    (defined(__STDC_WANT_LIB_EXT1__) && __STDC_WANT_LIB_EXT1__ >= 1) ||        \
    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)

#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 __STDDEF_H
#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
#define __need_NULL
#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. */
#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