Re: socket.h patch -- right way

Khimenko Victor (khim@sch57.msk.ru)
Thu, 30 Apr 1998 02:18:51 +0400 (MSD)

29-Apr-98 13:21 you wrote:
>
> A struct cmsghdr * is returned, so we shouldn't return (void*)NULL but
> (struct cmsghdr*) NULL . This only matter in C++, I guess.
>
This is not matter even for C++ :-)) Since NULL is 0 in C++ and 0 in C++ could
be AUTOMATICALLY casted to ANY pointer. This is true for ANSI C++ standard and
for gcc/pgcc/egcs... Unfortunatelly sched.h define NULL as ((void *) 0) even in
C++ :-(( May be better use the following patch (since NULL defined as
((void *) 0) will not good for C++ anyway)?:

--- include/linux/fs.h Tue Apr 21 03:02:37 1998
+++ include/linux/fs.h Thu Apr 30 02:28:27 1998
@@ -61,7 +61,11 @@
#define WRITEA 3 /* write-ahead - don't block if no resources */

#ifndef NULL
+#ifdef __cplusplus
+#define NULL 0
+#else
#define NULL ((void *) 0)
+#endif
#endif

#define NIL_FILP ((struct file *)0)
--- include/linux/posix_types.h Tue Dec 9 11:07:19 1997
+++ include/linux/posix_types.h Thu Apr 30 02:31:02 1998
@@ -8,7 +8,11 @@
*/

#ifndef NULL
+#ifdef __cplusplus
+# define NULL 0
+#else
# define NULL ((void *) 0)
+#endif
#endif

/*
--- include/linux/sched.h Tue Apr 21 03:02:38 1998
+++ include/linux/sched.h Thu Apr 30 02:28:14 1998
@@ -99,7 +99,11 @@
};

#ifndef NULL
+#ifdef __cplusplus
+#define NULL 0
+#else
#define NULL ((void *) 0)
+#endif
#endif

#ifdef __KERNEL__
--- include/linux/stddef.h Sat Nov 23 13:29:04 1996
+++ include/linux/stddef.h Thu Apr 30 02:29:44 1998
@@ -2,7 +2,11 @@
#define _LINUX_STDDEF_H

#undef NULL
+#ifdef __cplusplus
+#define NULL 0
+#else
#define NULL ((void *)0)
+#endif

#undef offsetof
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
--- include/linux/string.h Sat Apr 4 06:05:41 1998
+++ include/linux/string.h Thu Apr 30 02:29:03 1998
@@ -4,7 +4,11 @@
#include <linux/types.h> /* for size_t */

#ifndef NULL
+#ifdef __cplusplus
+#define NULL 0
+#else
#define NULL ((void *) 0)
+#endif
#endif

#ifdef __cplusplus

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