Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10 5/3/83; site bbncca.ARPA
Path: utzoo!linus!vaxine!wjh12!bbncca!keesan
From: keesan@bbncca.ARPA (Morris Keesan)
Newsgroups: net.lang.c
Subject: Re: Question about toupper and tolower
Message-ID: <300@bbncca.ARPA>
Date: Thu, 10-Nov-83 15:34:15 EST
Article-I.D.: bbncca.300
Posted: Thu Nov 10 15:34:15 1983
Date-Received: Fri, 11-Nov-83 23:36:08 EST
References: <1764@fortune.UUCP>
Organization: Bolt, Beranek and Newman, Cambridge, Ma.
Lines: 10

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The definitions of toupper and tolower on BBN UNIX systems were changed nearly
three years ago to leave the character in the desired case if it already is.
It doesn't appear to have broken anything in that amount of time.  Incidentally,
the efficient way to do this is NOT to build a definition that looks like
(isupper(c)?(c):toupper(c)), but simply to replace the addition and subtraction
operations with bitwise AND and OR operators to turn on or off the ASCII
lower-case bit.
						Morris M. Keesan
						decvax!bbncca!keesan