Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!nrl-cmf!cmcl2!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn )
Newsgroups: comp.lang.c
Subject: Re: getch() and getche() in MSC 4.0
Message-ID: <8719@smoke.BRL.MIL>
Date: 22 Oct 88 19:07:34 GMT
References: <10508@dartvax.Dartmouth.EDU>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 7

In article <10508@dartvax.Dartmouth.EDU> jalphin@prism.clemson.edu writes:
>	c = toupper(getch());

The problem is almost certainly due to toupper() being implemented as an
"unsafe" macro, i.e. one that evaluates its argument more than once, so
that if the argument has side-effects the result is different from what
a function toupper() would have done.  Obviously getch() has side-effects.