use of if (!cptr) and if (cptr), where cptr is a *

Andrew Koenig ark at alice.UUCP
Tue Jul 18 04:55:36 AEST 1989


In article <10099 at mpx2.mpx.com>, erik at 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 at europa.att.com



More information about the Comp.lang.c mailing list