Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!yale!mintaka!spdcc!ima!haddock!karl
From: karl@haddock.ima.isc.com (Karl Heuer)
Newsgroups: comp.lang.c
Subject: Re: Is there a good example of how toupper() works?
Message-ID: <18575@haddock.ima.isc.com>
Date: 18 Oct 90 21:49:00 GMT
References: <2466@ux.acs.umn.edu> <wb76pN600awOE3SaQz@andrew.cmu.edu> <1990Oct17.170914.683@wpi.WPI.EDU>
Reply-To: karl@ima.isc.com (Karl Heuer)
Organization: Interactive Systems, Cambridge, MA 02138-5302
Lines: 22

In article <1990Oct17.170914.683@wpi.WPI.EDU> profesor@wpi.WPI.EDU (Matthew E Cross) writes:
>Nope, won't work - the return value of 'toupper' is undefined if the input is
>not a lowercase character.

Fixed in ANSI C.

For those who are using pre-ANSI systems where this doesn't hold, I recommend
coding in ANSI style, and writing your own ANSI-compatible headers and
libraries as needed.  This minimizes the trauma when you finally graduate to
ANSI C.  My personal ansi/ctype.h is:
	#include "/usr//include/ctype.h"
	#undef tolower
	#undef toupper
	#if defined(__STDC__)
	extern int toupper(int);
	extern int tolower(int);
	#else
	extern int toupper();
	extern int tolower();
	#endif

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