bug in assignment containing side-effect

Article View: gnu.gcc.bug

Article #451

#451

From: Paul SPEE
Date: Tue, 11 Jul 1989 05:36

26 lines
956 bytes

I was pointed out the following bug:

#include <ctype.h>

char	*string = "aBcDeF";

main()
{
     char *p = string;

     printf("%s\n", string);
     while (*p)
     {
	  *p++ = islower(*p) ? toupper(*p) : *p;
     }
     printf("%s\n", string);
}

SUN cc result:		gcc v1.22 result:
aBcDeF			aBcDeF
ABCDEF			BCDEF

The cause is that gcc evaluates the lhs first. Is this fixed in later
version or is this ANSI behavior?

Paul Spee	- spee%qmflp.junet@RELAY.CS.NET

Technical Details

Message-ID: <366@qmfl.qmflp.JUNET>

Path:

arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!gatech!tut.cis.ohio-state.edu!cs.utexas.edu!pp!milano!bigtex!rena!kogwy!ccut!titcca!anprda!qmfl!spee

Show Full Headers

Complete Article Headers

Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!gatech!tut.cis.ohio-state.edu!cs.utexas.edu!pp!milano!bigtex!rena!kogwy!ccut!titcca!anprda!qmfl!spee
From: spee@qmfl.qmflp.JUNET (Paul SPEE)
Newsgroups: gnu.gcc.bug
Subject: bug in assignment containing side-effect
Message-ID: <366@qmfl.qmflp.JUNET>
Date: 11 Jul 89 05:36:53 GMT
Reply-To: spee%qmflp.junet@RELAY.CS.NET (Paul SPEE)
Organization: Quantum Magneto Flux Logic Project, Tsukiji, Tokyo
Lines: 26