Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84; site brl-tgr.ARPA
Path: utzoo!linus!philabs!cmcl2!seismo!brl-tgr!gwyn
From: gwyn@brl-tgr.ARPA (Doug Gwyn <gwyn>)
Newsgroups: net.lang.c
Subject: Re: if(p)
Message-ID: <1965@brl-tgr.ARPA>
Date: Mon, 7-Oct-85 19:21:18 EDT
Article-I.D.: brl-tgr.1965
Posted: Mon Oct  7 19:21:18 1985
Date-Received: Wed, 9-Oct-85 06:32:18 EDT
References: <1960@brl-tgr.ARPA>
Organization: Ballistic Research Lab
Lines: 18

>     Section 9.3 Conditional statement:
> 	if ( expression ) statement
> 	if ( expression ) statement else statement
>     In both cases the expression is evaluated and if it is non-zero,
                                                    ^^^^^^^^^^^^^^^^^
This implies a comparison against 0.  Therefore if "expression" is a
pointer, this is comparison of a pointer with 0, which is the special
case previously discussed.  There is no concept of "evaluates to zero"
independently of "comparison with zero".

>     the first substatement is executed.  In the second case the second
>     substatement is executed if the expression is 0.

Don't take K&R too much as gospel.  It is an excellent book,
but it really did not try to specify everything to the level
that a language lawyer would want.  (X3J11 is trying to do that.)
K&R has to be read with the attitude of extracting the "spirit"
of the language from what is implied as well as from what is said.