usr/src/uts/common/sys/null.h

   1 /*
   2  * This file and its contents are supplied under the terms of the
   3  * Common Development and Distribution License ("CDDL"), version 1.0.
   4  * You may only use this file in accordance with the terms of version
   5  * 1.0 of the CDDL.
   6  *
   7  * A full copy of the text of the CDDL should have accompanied this
   8  * source.  A copy of the CDDL is also available via the Internet at
   9  * http://www.illumos.org/license/CDDL.
  10  */
  11
  12 /*
  13  * Copyright 2014-2016 PALO, Richard.
  14  */
  15
  16 #ifndef _SYS_NULL_H
  17 #define _SYS_NULL_H
  18
  19 #include <sys/feature_tests.h>
  20
  21 #ifndef NULL
  22
  23 /*
  24  * POSIX.1-2008 requires that the NULL macro be cast to type void *.
  25  * Historically, this has not been done, so we only enable this in a
  26  * POSIX.1-2008 compilation environment.
  27  */
  28
  29 #if defined(_XPG7) && !defined(__cplusplus)
  30 #define NULL    ((void *)0)
  31 #else
  32
  33 /*
  34  * ISO C++ requires that the NULL macro be a constant integral type evaluating
  35  * to zero until C++11, and an integer or pointer literal with value zero from
  36  * C++11 onwards.
  37  */
  38
  39 #if defined(__cplusplus) && __cplusplus >= 201103L
  40 #define NULL    nullptr
  41 #else
  42 #if defined(_LP64)
  43 #define NULL    0L
  44 #else
  45 #define NULL    0
  46 #endif  /* _LP64 */
  47 #endif  /* C++11 */
  48 #endif  /* _XPG7 */
  49
  50 #endif  /* NULL */
  51
  52 #endif  /* _SYS_NULL_H */