Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!helios!bcm!shell!shell!rjohnson
From: rjohnson@shell.com (Roy Johnson)
Newsgroups: comp.lang.c
Subject: Re: increment casted void pointer  --  ANSI?
Message-ID: <RJOHNSON.91Mar28112705@olorin.shell.com>
Date: 28 Mar 91 17:27:05 GMT
References: <4142@rwthinf.UUCP> <1991Mar8.165300.11692@zoo.toronto.edu>
	<288@nazgul.UUCP> <15589@smoke.brl.mil>
Sender: usenet@shell.shell.com (USENET News System)
Organization: Shell Development Company, Bellaire Research Center, Houston, TX
Lines: 39
In-Reply-To: gwyn@smoke.brl.mil's message of 26 Mar 91 22:22:11 GMT

In article <15589@smoke.brl.mil> gwyn@smoke.brl.mil (Doug Gwyn) writes:
> In article <288@nazgul.UUCP> bright@nazgul.UUCP (Walter Bright) writes:
> -In article <1991Mar8.165300.11692@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes:
> -The usual to do a 'type paint', which is to change the type of an object
> -without changing the bit pattern, is to:
> -	*(newtype *)&(object)

> A strictly conforming method is to use a union type.

So can you do

otype object;
newtype feech;

feech = ((union { newtype n; otype o;})object).n;

or

union {
  newtype n;
  otype   o;
} typeunion;

feech = ((union typeunion)object).n;

or do you have to do

union typeunion blah;

blah.o = object;
feech = blah.n;

?

Just what can we get away with, here?
--
======= !{sun,psuvax1,bcm,rice,decwrl,cs.utexas.edu}!shell!rjohnson =======
Feel free to correct me, but don't preface your correction with "BZZT!"
Roy Johnson, Shell Development Company