Change the definition of NULL on ia64 (for LP64 compilations) from

an int constant to a long constant. This change improves consistency
in the following two ways:
1. The first 8 arguments are always passed in registers on ia64, which
   by virtue of the generated code implicitly widens ints to longs and
   allows the use of an 32-bit integral type for 64-bit arguments.
   Subsequent arguments are passed onto the memory stack, which does
   not exhibit the same behaviour and consequently do not allow this.
   In practice this means that variadic functions taking pointers
   and given NULL (without cast) work as long as the NULL is passed
   in one of the first 8 arguments. A SIGSEGV is more likely the
   result if such would be done for stack-based arguments. This is
   due to the fact that the upper 4 bytes remain undefined.
2. All 64-bit platforms that FreeBSD supports, with the obvious
   exception of ia64, allow 32-bit integral types (specifically NULL)
   when 64-bit pointers are expected in variadic functions by way of
   how the compiler generates code. As such, code that works correctly
   (whether rightfully so or not) on any platform other than ia64, may
   fail on ia64.

To more easily allow tweaking of the definition of NULL, this commit
removes the 12 definitions in the various headers and puts it in a
new header that can be included whenever NULL is to be made visible.

This commit fixes GNOME, emacs, xemacs and a whole bunch of ports
that I don't particularly care about at this time...

1 files changed, 2 insertions, 4 deletions

diff --git a/include/dirent.h b/include/dirent.h
index f6e4ccd..d686daf 100644
--- a/include/dirent.h
+++ b/include/dirent.h
@@ -54,6 +54,8 @@
 
 #if __BSD_VISIBLE
 
+#include <sys/_null.h>
+
 /* definitions for library routines operating on directories. */
 #define	DIRBLKSIZ	1024
 
@@ -81,10 +83,6 @@ typedef struct _dirdesc {
 #define DTF_REWIND	0x0004	/* rewind after reading union stack */
 #define __DTF_READALL	0x0008	/* everything has been read */
 
-#ifndef NULL
-#define	NULL	0
-#endif
-
 #else /* !__BSD_VISIBLE */
 
 typedef	void *	DIR;