do not export kernel's NULL #define to userspace
authorLubos Lunak <l.lunak@suse.cz>
Wed, 21 Mar 2012 13:08:24 +0000 (14:08 +0100)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 14 Apr 2012 14:47:49 +0000 (07:47 -0700)
GCC's NULL is actually __null, which allows detecting some questionable
NULL usage and warn about it.  Moreover each platform/compiler should
have its own stddef.h anyway (which is different from linux/stddef.h).

So there's no good reason to leak kernel's NULL to userspace and
override what the compiler provides.

Signed-off-by: Luboš Luňák <l.lunak@suse.cz>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/stddef.h

index 6a40c76bdcf1a7732d71675d888e722aa0dc578c..1747b6787b9e90375827a9af75148bf420caf386 100644 (file)
@@ -3,14 +3,10 @@
 
 #include <linux/compiler.h>
 
+#ifdef __KERNEL__
+
 #undef NULL
-#if defined(__cplusplus)
-#define NULL 0
-#else
 #define NULL ((void *)0)
-#endif
-
-#ifdef __KERNEL__
 
 enum {
        false   = 0,