Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!mailrus!ncar!ico!haddock!karl
From: karl@haddock.ima.isc.com (Karl Heuer)
Newsgroups: comp.lang.c
Subject: Re: Operations on pointers to void.
Message-ID: <17443@haddock.ima.isc.com>
Date: 17 Aug 90 00:47:03 GMT
References: <482@array.UUCP> <1990Aug12.231202.23826@druid.uucp> <174@srchtec.UUCP> <1990Aug16.014947.1999@druid.uucp>
Reply-To: karl@kelp.ima.isc.com (Karl Heuer)
Organization: Interactive Systems, Cambridge, MA 02138-5302
Lines: 13

In article <1990Aug16.014947.1999@druid.uucp> darcy@druid.uucp (D'Arcy J.M. Cain) writes:
>If the language supported pointer arithmetic on void * this would be
>possible.  Note that GNU C does support it and I can't see any harm in it.

The potential harm is when somebody writes code like
	vp = (struct foo *)vp;
	... ++vp ...
without realizing that it doesn't do what was intended.  (Somebody *did*
recently post code much like this, in fact.)  This type of error will be
caught by the ANSI rule, which makes sense because `void' is an incomplete
type of undefined size.

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