Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!rutgers!sri-spam!nike!oliveb!sun!guy
From: guy@sun.uucp (Guy Harris)
Newsgroups: net.unix-wizards
Subject: Re: Microport Unix -- Large Model Problems
Message-ID: <8946@sun.uucp>
Date: Wed, 5-Nov-86 14:41:45 EST
Article-I.D.: sun.8946
Posted: Wed Nov  5 14:41:45 1986
Date-Received: Wed, 5-Nov-86 22:44:26 EST
References: <188@vsedev.VSE.COM> <401@maynard.UUCP> <245@rabbit1.UUCP> <347@prairie.UUCP> <405@maynard.UUCP>
Distribution: net
Organization: Sun Microsystems, Inc.
Lines: 18

> I wonder why stdio.h doesn't just declare NULL as "(char *) 0", or,
> in the brave new world of ANSI X-whatever, "(void *) 0"?  This should
> do all the right things.

No, it shouldn't.  Passing a "(char *)0" to a routine that expects an "int
*" of some sort is NOT guaranteed to work.  If, in fact, you have a machine
on which "char *" is longer than "int *", it is very unlikely to work.

In the brave new world of ANSI X3J11, the right thing to do is to use
function prototypes; if you do this, almost all the 0's will be
automatically converted into null pointers of the appropriate type by the
compiler.  (It still won't work for "execl"; if you hack NULL to be
"(char *)0", it fixes *this* case, but it may not work for some routine that
expects an "(int *)0" at the end of its argument list.)
-- 
	Guy Harris
	{ihnp4, decvax, seismo, decwrl, ...}!sun!guy
	guy@sun.com (or guy@sun.arpa)