do not export kernel's NULL #define to userspace

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>

do not export kernel's NULL #define to userspace
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>
Lubos Lunak · Linus Torvalds
1 parent 668ce0ac70
Showing 1 changed file with 2 additions and 6 deletions Side-by-side Diff
include/linux/stddef.h
@@ -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,
...	...	@@ -3,14 +3,10 @@
3	3
4	4	#include <linux/compiler.h>
5	5
	6	+#ifdef __KERNEL__
	7	+
6	8	#undef NULL
7		-#if defined(__cplusplus)
8		-#define NULL 0
9		-#else
10	9	#define NULL ((void *)0)
11		-#endif
12		-
13		-#ifdef __KERNEL__
14	10
15	11	enum {
16	12	false = 0,