Path: utzoo!attcan!uunet!lll-winken!ames!xanth!mcnc!rti!xyzzy!throopw
From: throopw@xyzzy.UUCP (Wayne A. Throop)
Newsgroups: comp.lang.c
Subject: Re: How to use toupper()
Message-ID: <2792@xyzzy.UUCP>
Date: 12 Jan 89 20:01:56 GMT
References: <2537@xyzzy.UUCP> <189@becker.UUCP> <9256@smoke.BRL.MIL> <2581@ficc.uu.net> <1989Jan6.231955.7445@sq.uucp> <11391@haddock.ima.isc.com>
Organization: Data General, RTP NC.
Lines: 30

> karl@haddock.ima.isc.com (Karl Heuer)
>> msb@sq.com (Mark Brader)
>>The best you can do is to avoid "char" altogether and use "unsigned char".
>>You probably have to do it throughout the program, in fact.
> If the program has to be strictly conforming, you may be right.  (But then
> string literals, and functions that expect `char *' arguments, may screw
> things up; casting the pointers ought to be safe, though.)

If (ah say *IF*) it ought to be safe to cast pointers between (char *)
and (unsigned char *) types, why can't the problematical case conversion
be done like so:

        unsigned char *p;
        char *s;
        ...
        for( p=(unsigned char *)s; *p; ++p )
            *p = toupper( *p );

But on the other hand... if the above code is unsafe (and I see nothing
in dpANS which makes it safe), why would it be safe to use unsigned
characters hither and thither and simply cast pointers to these to
apply standard signed-character-expecting library routines to them?

(Gad, don't the simplest issues turn out to be cans of worms at times?)

--
"I really ought to do better next year."
"It's the 'ought' that counts."
                                        --- paraphrase of Bloom County
-- 
Wayne Throop      <the-known-world>!mcnc!rti!xyzzy!throopw