Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!uunet!taumet!steve
From: steve@taumet.com (Stephen Clamage)
Newsgroups: comp.lang.c
Subject: Re: what is this supposed to do?
Keywords: left shift
Message-ID: <689@taumet.com>
Date: 24 Apr 91 15:08:45 GMT
References: <1991Apr22.225641.1122@midway.uchicago.edu>
Organization: Taumetric Corporation, San Diego
Lines: 16

langer@gibbs.uchicago.edu (Steve Langer) writes:

>What is the expected output from the following program? Is it defined?

>#include <stdio.h>
>main() {
>   printf("1 << 32 = %o\n", ((unsigned) 1) << 32);
>}

It is not defined, so the variation in outputs you got is legal.
In 3.3.7, the Standard says "If the value of the right operand
[of the shift operator] ... is greater than or equal to the width in
bits of the promoted left operand, the behavior is undefined."
-- 

Steve Clamage, TauMetric Corp, steve@taumet.com