Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83; site mcgill-vision.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!allegra!mit-eddie!genrad!panda!talcott!harvard!seismo!cmcl2!philabs!micomvax!musocs!mcgill-vision!mouse
From: mouse@mcgill-vision.UUCP (der Mouse)
Newsgroups: net.lang.c
Subject: Re: how has C bitten you?
Message-ID: <132@mcgill-vision.UUCP>
Date: Fri, 23-Aug-85 04:34:51 EDT
Article-I.D.: mcgill-v.132
Posted: Fri Aug 23 04:34:51 1985
Date-Received: Sun, 25-Aug-85 02:13:27 EDT
References: <228@investor.UUCP>
Organization: McGill University, Montreal
Lines: 21


  [ ... ]
>	if(telno){		/*  should be if(*telno)  */
  [ ... ]

> Print statements showed the telno was being handed to the routine,
> but the if said nothing was there.  Turns out, on my system, the
> address of telno is NULL.  I needed to check the contents not the
> address!

Gee....and I thought a zero pointer was guaranteed not to point to
anything valid (K&R says this).  Or is NULL not a zero?!  No, you
are comparing to 0 not NULL.
-- 
					der Mouse

{ihnp4,decvax,akgua,etc}!utcsri!mcgill-vision!mouse
philabs!micomvax!musocs!mcgill-vision!mouse

Hacker: One responsible for destroying /
Wizard: One responsible for recovering it afterward