freebsd-skq/sys/sys/_null.h
Roman Divacky e9b123be77 Define NULL to be __null in a case of gnu c++. This makes sentinel attribute
work ok in C++. Note that we enable this only for gcc 4.x for any value
of x. The __null was introduced in gcc 4.1 (in fact it was commited
12 days after release of gcc 4.0) and as we have never released any version
of FreeBSD with gcc 4.0 nor ports support gcc 4.0.x this is a safe check.

Using __GNUC_PREREQ__ would require us to include cdefs.h in params.h so
we just check __GNUC__.

Approved by:	kib (mentor)
Tested by:	exp build of ports (done by pav)
Tested by:	make universe (done by me)
2009-01-29 16:51:09 +00:00

46 lines
1.6 KiB
C

/*-
* Copyright (c) 2003 Marcel Moolenaar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef NULL
#if defined(_KERNEL) || !defined(__cplusplus)
#define NULL ((void *)0)
#else
#if defined(__GNUG__) && defined(__GNUC__) && __GNUC__ >= 4
#define NULL __null
#else
#if defined(__LP64__)
#define NULL (0L)
#else
#define NULL 0
#endif /* __LP64__ */
#endif /* __GNUG__ */
#endif /* _KERNEL || !__cplusplus */
#endif