clang/lib/Headers/stdarg.h

   1 /*===---- stdarg.h - Variable argument handling ----------------------------===
   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 stdarg.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 stdarg.h
  20  * When SM.A builds, __STDARG_H will be defined. When SM.B builds, the
  21  * definition from SM.A will leak when building without local submodule
  22  * visibility. stdarg.h wouldn't include any of its implementation headers, and
  23  * SM.B wouldn't import any of the stdarg modules, and SM.B's `export *`
  24  * wouldn't export any stdarg interfaces as expected. However, since stdarg.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(__STDARG_H) || __has_feature(modules) ||                          \
  32     defined(__need___va_list) || defined(__need_va_list) ||                    \
  33     defined(__need_va_arg) || defined(__need___va_copy) ||                     \
  34     defined(__need_va_copy)
  35
  36 #if !defined(__need___va_list) && !defined(__need_va_list) &&                  \
  37     !defined(__need_va_arg) && !defined(__need___va_copy) &&                   \
  38     !defined(__need_va_copy)
  39 #define __STDARG_H
  40 #define __need___va_list
  41 #define __need_va_list
  42 #define __need_va_arg
  43 #define __need___va_copy
  44 /* GCC always defines __va_copy, but does not define va_copy unless in c99 mode
  45  * or -ansi is not specified, since it was not part of C90.
  46  */
  47 #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) ||              \
  48     (defined(__cplusplus) && __cplusplus >= 201103L) ||                        \
  49     !defined(__STRICT_ANSI__)
  50 #define __need_va_copy
  51 #endif
  52 #endif
  53
  54 #ifdef __need___va_list
  55 #include <__stdarg___gnuc_va_list.h>
  56 #undef __need___va_list
  57 #endif /* defined(__need___va_list) */
  58
  59 #ifdef __need_va_list
  60 #include <__stdarg_va_list.h>
  61 #undef __need_va_list
  62 #endif /* defined(__need_va_list) */
  63
  64 #ifdef __need_va_arg
  65 #include <__stdarg_va_arg.h>
  66 #undef __need_va_arg
  67 #endif /* defined(__need_va_arg) */
  68
  69 #ifdef __need___va_copy
  70 #include <__stdarg___va_copy.h>
  71 #undef __need___va_copy
  72 #endif /* defined(__need___va_copy) */
  73
  74 #ifdef __need_va_copy
  75 #include <__stdarg_va_copy.h>
  76 #undef __need_va_copy
  77 #endif /* defined(__need_va_copy) */
  78
  79 #endif