Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!sharkey!mcf!mibte!gamma!thumper!ulysses!andante!alice!ark
From: ark@alice.UUCP (Andrew Koenig)
Newsgroups: comp.lang.c
Subject: Re: use of if (!cptr) and if (cptr), where cptr is a *
Keywords: * != int
Message-ID: <9626@alice.UUCP>
Date: 17 Jul 89 18:55:36 GMT
References: <10099@mpx2.mpx.com>
Organization: AT&T Bell Laboratories, Liberty Corner NJ
Lines: 26

In article <10099@mpx2.mpx.com>, erik@mpx2.mpx.com (Erik Murrey) writes:

> char	*cptr, *malloc();	/* ok, so maybe malloc is void * by now... */

> x()
> {
> 	cptr= malloc(...);
> 	if (!cptr)
> 		fatal("cannot malloc");
> 	...
> }

No problem.

The folowing expressions are all equivalent in this context:

	!cptr
	cptr==0
	cptr==NULL
	cptr==(char *)0
	cptr==(char *)NULL

Which one you use is a matter of personal taste and style.
-- 
				--Andrew Koenig
				  ark@europa.att.com