Path: utzoo!utgpu!attcan!uunet!husc6!mailrus!cornell!uw-beaver!fluke!ssc-vax!cxsea!blm
From: blm@cxsea.UUCP (Brian Matthews)
Newsgroups: comp.lang.c
Subject: Re: question about shift operator
Message-ID: <2553@cxsea.UUCP>
Date: 2 Nov 88 21:11:57 GMT
References: <786@gtx.com>
Reply-To: blm@cxsea.UUCP (Brian Matthews)
Distribution: na
Organization: Computer X Inc.
Lines: 19

Randy D. Miller (randy@gtx.UUCP) writes:
|I've seen conflicting information about the shift operator in cases
|where operand2 is exactly equal to the number of bits in the object.
|E.g., with a 32 bit int, what must the following do?
|     int n;
|     n <<= 32;
|K&R 1st ed. seems to indicate the operation is undefined, but does
|the proposed standard change this?  

From section 3.3.7 "Bitwise shift operators" of the ANSI draft standard,
in the first paragraph under Semantics:

"...If the value of the right operand is negative or greater than or
equal to the width in bits of the promoted left operand, the behavior is
undefined."

-- 
Brian L. Matthews  blm@cxsea.UUCP   ...{mnetor,uw-beaver!ssc-vax}!cxsea!blm
+1 206 251 6811    Computer X Inc. - a division of Motorola New Enterprises