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From: karl@haddock.ima.isc.com (Karl Heuer)
Newsgroups: comp.lang.c
Subject: Re: index and rindex question...
Message-ID: <15826@haddock.ima.isc.com>
Date: 1 Feb 90 16:33:33 GMT
References: <11716.25C6818B@urchin.fidonet.org>
Reply-To: karl@haddock.ima.isc.com (Karl Heuer)
Organization: Interactive Systems, Cambridge, MA 02138-5302
Lines: 13

In article <11716.25C6818B@urchin.fidonet.org> Bob.Stout@p6.f506.n106.z1.fidonet.org (Bob Stout) writes:
>Based on this usage, I use:
>#define index(s,c)  ((strchr((s),(c))) ? (size_t)(strchr((s),(c))-(s)) : -1)
>#define rindex(s,c) ((strrchr((s),(c))) ? (size_t)(strrchr((s),(c))-(s)) : -1)
>
>Note that these are *not* safe macros since the `s' argument may be
>evaluated three times and the `c' argument twice.

They also do twice as much work, and would be confusing to anyone who expects
those names to have the V7/BSD semantics.  Wouldn't it be simpler to just use
strchr and strrchr, which should be present in any modern system?

Karl W. Z. Heuer (karl@ima.ima.isc.com or harvard!ima!karl), The Walking Lint