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From: mouse@mcgill-vision.UUCP
Newsgroups: comp.lang.c
Subject: Re: Use of NULL as a pointer in C
Message-ID: <559@mcgill-vision.UUCP>
Date: Sat, 22-Nov-86 17:47:27 EST
Article-I.D.: mcgill-v.559
Posted: Sat Nov 22 17:47:27 1986
Date-Received: Mon, 24-Nov-86 19:29:08 EST
References: <1376@batcomputer.TN.CORNELL.EDU> <8957@sun.uucp> <250@rabbit1.UUCP>
Organization: McGill University, Montreal
Lines: 30

In article <250@rabbit1.UUCP>, barber@rabbit1.UUCP (Steve Barber) writes:
> The use of the identifier NULL, as defined by stdio.h in all UNIXes
> I've ever seen [...], by itself as any kind of pointer, is a
> non-portable usage and as such is incorrect [...]

Nearly.  It *is* portable to write (assuming NULL is 0, as it is on our
system)
	ptr_var = NULL;
or
	if (ptr_expr == NULL)
(or !=).  It is *not* portable to write
	setbuf(stdout,NULL); /* should be (char *)NULL */
(even aside from the issue of setbuf()'s portability).

> When writing code, bite the bullet and type those extra 8 or so
> characters [...]: (char *) NULL, (int *) NULL, or [whatever].

I prefer to simply never use NULL.  I write my code with zeros.  This
way I don't get bitten when porting to a system where some well-meaning
clod with the famous "little learning" decided to "avoid" the "problem"
and make NULL ((char *)0).

					der Mouse

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