Path: utzoo!mnetor!uunet!husc6!sri-unix!quintus!sun!decwrl!pyramid!prls!philabs!pwa-b!mmintl!franka
From: franka@mmintl.UUCP (Frank Adams)
Newsgroups: comp.lang.c
Subject: Re: Why NULL is 0
Message-ID: <2771@mmintl.UUCP>
Date: 17 Mar 88 15:46:18 GMT
References: <10576@mimsy.UUCP> <124@polygen.UUCP> <800@zippy.eecs.umich.edu>
Reply-To: franka@mmintl.UUCP (Frank Adams)
Organization: Ashton-Tate Corporation, East Hartford Development Center
Lines: 17

In article <800@zippy.eecs.umich.edu> janc@palam.eecs.umich.edu (Jan Wolter) writes:
>As I read K&R, a null pointer is only produced when a *constant* 0 is assigned
>to a pointer.  When an integer is assigned to a zero, K&R seems to suggest
>that a bitwise copy is done, which may not be the same thing at all.  This
>seems to be the only case in C where "a=(b=c)" is not equivalent to "a=c,b=c".

It isn't.  Try:

double d;
int i;
d = (i = 1.5);

In general, "a=(b=c)" is eqivalent to "b=c,a=b".
-- 

Frank Adams                           ihnp4!philabs!pwa-b!mmintl!franka
Ashton-Tate          52 Oakland Ave North         E. Hartford, CT 06108