Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!ico!ism780c!haddock!karl
From: karl@haddock.ima.isc.com (Karl Heuer)
Newsgroups: comp.lang.c
Subject: Re: checking for overflow in C
Message-ID: <13003@haddock.ima.isc.com>
Date: 8 May 89 22:30:53 GMT
References: <13367@dartvax.Dartmouth.EDU> <10218@smoke.BRL.MIL>
Reply-To: karl@haddock.ima.isc.com (Karl Heuer)
Organization: Interactive Systems, Boston
Lines: 13

In article <10218@smoke.BRL.MIL> gwyn@brl.arpa (Doug Gwyn) writes:
>In <13367@dartvax.Dartmouth.EDU> shallit@eleazar (Jeffrey Shallit) writes:
>>... enlighten me about the officially approved way of checking overflow when
>>multiplying two integers.
>
>How did you get your algorithm into the state where an overflow is
>even possible?

Let's take a concrete example.  How do you think one should code the
implementation of the ANSI C function strtol(), which is required to detect
integer overflow and return ERANGE in this case?

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