Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!nuchat!moray!urchin!p6.f506.n106.z1.fidonet.org!Bob.Stout
From: Bob.Stout@p6.f506.n106.z1.fidonet.org (Bob Stout)
Newsgroups: comp.lang.c
Subject: Re: index and rindex question...
Message-ID: <11716.25C6818B@urchin.fidonet.org>
Date: 30 Jan 90 16:11:39 GMT
Sender: ufgate@urchin.fidonet.org (newsout1.26)
Organization: FidoNet node 1:106/506.6 - Fulcrum's Edge, Spring TX
Lines: 15

In an article of <27 Jan 90 02:04:19 GMT>, (Conor P. Cahill) writes:

 >They are equivalent to the system V functions strchr() and strrchr(),
 >respectively.

  Both the strchr() and strrchr() functions made it into the ANSI spec while  
index() and rindex() didn't. I believe this was because the latter two  
functions on some systems return an int offset of the character rather than a  
pointer to it. 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.