svn commit: r187895 - head/sys/sys

[Roman Divacky]

Author: rdivacky
Date: Thu Jan 29 16:51:09 2009
New Revision: 187895
URL: http://svn.freebsd.org/changeset/base/187895

Log:
  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)

Modified:
  head/sys/sys/_null.h

Modified: head/sys/sys/_null.h
==============================================================================
--- head/sys/sys/_null.h	Thu Jan 29 16:47:15 2009	(r187894)
+++ head/sys/sys/_null.h	Thu Jan 29 16:51:09 2009	(r187895)
@@ -31,11 +31,15 @@
 #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