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From: salomon@ccu.umanitoba.ca (Dan Salomon)
Newsgroups: comp.lang.c
Subject: Re: Is there a good example of how toupper() works?
Message-ID: <1990Oct17.190701.21304@ccu.umanitoba.ca>
Date: 17 Oct 90 19:07:01 GMT
References: <2466@ux.acs.umn.edu> <wb76pN600awOE3SaQz@andrew.cmu.edu>
Organization: University of Manitoba, Winnipeg, Canada
Lines: 20

In article <wb76pN600awOE3SaQz@andrew.cmu.edu> jh4o+@andrew.cmu.edu (Jeffrey T. Hutzelman) writes:
>Try this one:
>
>void strupper(char *str)
>{
>for (;*str!='\0';str++)
>	*str=toupper(*str);
>}

There is a problem with this solution on some systems.
Berkeley UNIX BSD 4.3 requires that the parameter of toupper
be a lowercase letter.  The result is undefined if it is not.
Therefore the test using islower may be necessary on some systems.
This makes toupper pretty useless in portable programs, but
those are the breaks.
-- 

Dan Salomon -- salomon@ccu.UManitoba.CA
               Dept. of Computer Science / University of Manitoba
	       Winnipeg, Manitoba  R3T 2N2 / (204) 275-6682