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From: qwerty@drutx.UUCP
Newsgroups: net.unix,net.ai,net.wanted
Subject: Re: need xlisp help
Message-ID: <1181@drutx.UUCP>
Date: Fri, 28-Sep-84 10:03:54 EDT
Article-I.D.: drutx.1181
Posted: Fri Sep 28 10:03:54 1984
Date-Received: Sat, 29-Sep-84 10:32:02 EDT
References: <331@hoxna.UUCP>
Organization: AT&T Information Systems Laboratories, Denver
Lines: 2

index == strchr, rindex == strrchr, identical declaration and arguments.
That's Berkley vs Sys V kind of thing I believe.