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From: bruce@seismo.gps.caltech.edu (Bruce Worden)
Newsgroups: comp.lang.c
Subject: Re: Is there a good example of how toupper() works?
Message-ID: <1990Oct18.182650.7188@nntp-server.caltech.edu>
Date: 18 Oct 90 18:26:50 GMT
References: <1990Oct17.170914.683@wpi.WPI.EDU> <11021@hubcap.clemson.edu>
Sender: bruce@seismo.gps.caltech.edu (Bruce Worden)
Organization: California Institute of Technology, CA
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svissag@hubcap.clemson.edu (Steve L Vissage II) writes:
>From article <1990Oct17.170914.683@wpi.WPI.EDU>, by profesor@wpi.WPI.EDU (Matthew E Cross):
>> Nope, won't work - the return value of 'toupper' is undefined if the input is
>> not a lowercase character.
>  
>So define your own toupper() macro.  That's what I did.
>#define toupper(ch) ((ch<123 && ch>96) ? ch-32 : ch)
> [ ... ]

I wouldn't recommend defining a macro with the same name as a library
function.  And from what I remember from the `toupper()' and `tolower()'
discussion here about three months ago, I think it was generally agreed 
that a macro that evaluates its argument three times must be used with 
great caution ( toupper(getchar()) can happen, e.g.), and that the simple 
subtraction ( ch-32 ) and comparisons ( ch<123, ch>96) are inherently
non-portable.

P.S. I, among others, missed the *duh = "hello"; bug.  My apologies.
--------------------------------------------------------------------------
C. Bruce Worden                            bruce@seismo.gps.caltech.edu
252-21 Seismological Laboratory, Caltech, Pasadena, CA 91125