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: <8723@smoke.BRL.MIL>
Date: 22 Oct 88 19:30:50 GMT
References: <10508@dartvax.Dartmouth.EDU> <7594@bloom-beacon.MIT.EDU>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 12

In article <7594@bloom-beacon.MIT.EDU> scs@adam.pika.mit.edu (Steve Summit) writes:
>If it is desirable for toupper to work correctly on characters
>that are nonalphabetic or already upper-case (I believe this
>property is called "idempotence," and as I said, it is a laudable
>goal), then the macro implementation has to be sacrificed, and
>toupper() made a proper function.

No, toupper() can be correctly implemented as a "safe" macro,
at least in an environment where all locales use character sets
that fit in 8-bit bytes.  Think about how other <ctype.h>
functions are typically implemented as safe macros and you
should be able to see how toupper() could be so done.