Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!seas.gwu.edu!xc215119
From: xc215119@seas.gwu.edu (David E. O'Brien)
Newsgroups: comp.lang.c
Subject: Re: What does ANSI C say about short circuit evaluation?
Message-ID: <3229@sparko.gwu.edu>
Date: 26 May 91 02:05:47 GMT
References: <1991May22.092404.25297@ucthpx.uct.ac.za>
Reply-To: xc215119@seas.gwu.edu ()
Organization: The George Washington University, Washington D.C.
Lines: 18

In article <1991May22.092404.25297@ucthpx.uct.ac.za> gram@uctcs.uucp (Graham Wheeler) writes:
>The following question has caused a bit of debate here in the last couple of
>days. There are two parts:
>
>i) Does ANSI C say that compilers can rearrange the order of expression 
>	evaluation?
>
>ii) Does it say that Boolean expressions must be evaluated with short-
>	circuit evaluation?
>

Yes, ANSI C requires boolean short circuiting and that the C compiler must
process if(...) in the order from left to right.  In fact you can read this
from K & R 2nd ed.  They even say that many, many C programmers DEPEND on
this fact and in your life as a programmer you are probably going to come
upon some code that depends on this, so get used to it.

-- David O'Brien