Path: utzoo!attcan!uunet!munnari.oz.au!mel.dit.csiro.au!yarra!melba.bby.oz.au!zvs
From: zvs@bby.oz.au (Zev Sero)
Newsgroups: comp.lang.c
Subject: Re: Is there a good example of how toupper() works?
Message-ID: <1990Nov12.005245.14069@melba.bby.oz.au>
Date: 12 Nov 90 00:52:45 GMT
References: <1990Oct17.170914.683@wpi.WPI.EDU> <11021@hubcap.clemson.edu>
	<152580@felix.UUCP> <1990Nov7.043705.15051@robot.in-berlin.de>
Sender: news@melba.bby.oz.au
Organization: Burdett, Buckeridge and Young Ltd.
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In-Reply-To: karl@robot.in-berlin.de's message of 7 Nov 90 04:37:05 GMT

>>>>> On 7 Nov 90 04:37:05 GMT, karl@robot.in-berlin.de (Karl-P. Huestegge) said:
Karl> One additional advice: Please don't use isascii() in text-functions,
Karl> because this forbits all international chars > 127. Use isprint()
Karl> instead (or whatever is appropriate).

Unfortunately, in many implementations, including SunOS, the only
ctype.h functions/macros that are guaranteed to work on chars >127 are
isascii and toascii.  If you want your code to work on such systems,
i.e. you are doing things like 
  c = isupper (c) ? tolower (c) : c;
which is unnecessary in standard C, then you must also use isascii.
  c = isascii (c) && isupper (c) ? tolower (c) : c;

To find out whether a character can safely be sent to a printer, in
such an implementation, you must use 
  if (isascii (c) && isprint (c))
otherwise, as I learned the hard way, your program will dump core.
---
                                Zev Sero  -  zvs@bby.oz.au
As I recall, zero was invented by Arabic mathematicians
thousands of years ago.  It's a pity it still frightens
or confuses people.           - Doug Gwyn