clang/lib/Headers/__stddef_null.h

   1 /*===---- __stddef_null.h - Definition of NULL -----------------------------===
   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(NULL) || !__building_module(_Builtin_stddef)
  11
  12 /* linux/stddef.h will define NULL to 0. glibc (and other) headers then define
  13  * __need_NULL and rely on stddef.h to redefine NULL to the correct value again.
  14  * Modules don't support redefining macros like that, but support that pattern
  15  * in the non-modules case.
  16  */
  17 #undef NULL
  18
  19 #ifdef __cplusplus
  20 #if !defined(__MINGW32__) && !defined(_MSC_VER)
  21 #define NULL __null
  22 #else
  23 #define NULL 0
  24 #endif
  25 #else
  26 #define NULL ((void*)0)
  27 #endif
  28
  29 #endif