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From: walter@hpclwjm.HP.COM (Walter Murray)
Newsgroups: comp.lang.c
Subject: Re: Re: use of if (!cptr) and if (cptr), where cptr is a *)
Message-ID: <660046@hpclwjm.HP.COM>
Date: 26 Jul 89 16:44:37 GMT
References: <10099@mpx2.mpx.com>
Organization: Hewlett-Packard Calif. Language Lab
Lines: 17

Jeff Leyser writes:

> OK, this may be meaningless, but out of curiosity is:
> 	if (cptr == (int) 0)
> illegal C, or simply compleat garbage?

It's perfectly legal, if a little misleading.  As a further
examle of the latitude you have in writing a null pointer
constant, the following would also be legal.

   if (cptr == (signed short)0.3+sizeof(char)-'\1'
	       +sizeof((long int*)myfunc()+3,000)-sizeof'M');

I think any ANSI-conforming compiler will accept this statement.

Walter Murray
Not speaking for Hewlett-Packard or X3J11