standards/50889: NULL defined as 0 instead of (void *)0

[M. Warner Losh]

In message: <20030421104840.GA92922 at falcon.midgard.homeip.net>
            Erik Trulsson <ertr1013 at student.uu.se> writes:
: On Mon, Apr 21, 2003 at 02:01:06AM -0600, M. Warner Losh wrote:
: > I have a #define in my tree that I switch back and forth from time to
: > time:
: > 
: > #if defined(_cplusplus) || !defined(_NULL_VOID)
: > #define NULL 0L
: 
: Why not just plain 0?
: I think either will work fine so it doesn't matter really matter much
: but I am a bit curious.

Strange, but legal, to catch more issues.

: > #else
: > #define NULL (void *) 0
: 
: Won't work correctly.  You need to use ((void*)0) instead with the
: extra parenthesis.  Otherwise expressions like 'sizeof NULL' will fail
: to compile.

Yes, I didn't cut and paste, but rather typed from memory.

Warner