How to use toupper()

[Wayne A. Throop]

> karl at haddock.ima.isc.com (Karl Heuer)
>> msb at 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