Xref: utzoo comp.unix.questions:15908 comp.lang.c:21136
Path: utzoo!attcan!uunet!wuarchive!brutus.cs.uiuc.edu!tut.cis.ohio-state.edu!att!chinet!john
From: john@chinet.chi.il.us (John Mundt)
Newsgroups: comp.unix.questions,comp.lang.c
Subject: Re: moving upper case names to lower case
Message-ID: <9346@chinet.chi.il.us>
Date: 24 Aug 89 16:58:40 GMT
References: <20672@adm.BRL.MIL> <9326@chinet.chi.il.us> <2336@oakhill.UUCP>
Reply-To: john@chinet.chi.il.us (John Mundt)
Followup-To: comp.unix.questions
Organization: Chinet - Public Access Unix
Lines: 29

In article <2336@oakhill.UUCP> stevenw@oakhill.UUCP (Steven Weintraub) writes:
>> 	while ((c = getchar()) != EOF)
>> 		putchar(tolower(c));
>I should point out there is a risk in using tolower like this.  Some
>machines define tolower as ((c)-'A'+'a') (like some sun systems).
>This works well if the character is an upper case letter but it will
>translate 'FOO.c' to 'fooN^C'.

Are you sure that tolower() and _tolower() aren't being confused?  The
latter is a macro that just takes a value and |= 040 to it to make it
lower case, since it requires that an upper case letter be sent to it.

tolower(), on the other hand, is a function that firsts checks to see if
the value sent to it is uppercase, and only then does it do anything.

Quoting from the man page, 

"..tolower has as a domain the rainge of getc(3S):  the integers from
-1 to 255.  If the argument of tolower represents an 
upper-case letter, the result is the corresponding lower-case letter.
All other arguments in the domain are returned unchanged."
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


-- 
---------------------
John Mundt   Teachers' Aide, Inc.  P.O. Box 1666  Highland Park, IL
john@chinet.chi.il.us
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