Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!think!snorkelwacker!spdcc!ima!haddock!karl
From: karl@haddock.ima.isc.com (Karl Heuer)
Newsgroups: comp.lang.c
Subject: Re: DEFINITE bug in Turbo C 2.0 (WHO'S GOT THE BUG????)
Message-ID: <16269@haddock.ima.isc.com>
Date: 23 Mar 90 21:35:00 GMT
References: <802@zeusa.UUCP> <946@lectroid.sw.stratus.com> <16259@haddock.ima.isc.com> <1990Mar23.073923.6425@cs.eur.nl>
Reply-To: karl@haddock.ima.isc.com (Karl Heuer)
Organization: Interactive Systems, Cambridge, MA 02138-5302
Lines: 13

In article <1990Mar23.073923.6425@cs.eur.nl> reino@cs.eur.nl (Reino de Boer) writes:
>Now, this all depends on the relative precedence of "++" and "*", and
>that is all it should depend on.  Please correct me if I'm wrong

You're wrong.  For example, another valid computation of "x = ++a * ++a" is
"r1 = a+1; r2 = a+1; x = r1*r2; ++a; ++a;".  The only constraint on the timing
of side effects is that they must take place after the previous sequence point
and before the next one.

The bottom line is: that code does not produce a well-defined result.  Don't
write code like that.

Karl W. Z. Heuer (karl@ima.ima.isc.com or harvard!ima!karl), The Walking Lint