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From: vishniac@wanginst.UUCP (Ephraim Vishniac)
Newsgroups: net.lang.c
Subject: Re: Re: if (p), where p is a pointer
Message-ID: <1083@wanginst.UUCP>
Date: Fri, 13-Sep-85 08:06:20 EDT
Article-I.D.: wanginst.1083
Posted: Fri Sep 13 08:06:20 1985
Date-Received: Sat, 14-Sep-85 03:55:53 EDT
References: <118@mit-hector.UUCP> <4300@alice.UUCP>
Organization: Wang Institute, Tyngsboro, Ma.  01879
Lines: 21

> > With all this talk about NULL pointers not necessarily being equal to 0,
> > I'm no longer sure what is and isn't portable code.  An C idiom I see 
> > (and write) frequently is
> >	<some type> *ptr;
> >	...
> >	if (ptr)
> >	   <statement>
> > Will this work correctly on a machine where NULL is not 0?
> 
> No, you don't need to say NULL explicitly.  The relevant rules are:

	1. You should only make explicit comparisons in your code *only* where
	   absolutely necessary.  Not only does this save at least 1% in
	   editing keystrokes, but it deters nosy people from reading (or,
	   at least, from understanding) your code.

The way I see it, portability is not the essential issue here: *clarity* is.
-- 
Ephraim Vishniac
  [apollo, bbncca, cadmus, decvax, harvard, linus, masscomp]!wanginst!vishniac
  vishniac%Wang-Inst@Csnet-Relay