Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!umd5!ncifcrf!nlm-mcs!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: comp.lang.c
Subject: Re: Structure pointer question
Message-ID: <8185@brl-smoke.ARPA>
Date: 29 Jun 88 17:00:38 GMT
References: <361@teletron.uucp> <8074@brl-smoke.arpa> <4524@haddock.isc.com> <5925@aw.sei.cmu.edu> <389@proxftl.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) )
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 8

In article <389@proxftl.UUCP> bill@proxftl.UUCP (T. William Wells) writes:
>The C standard should make that explicit, don't you think?

It's been known for many years that the logic of C requires that
structure pointers all "smell the same" in a certain sense (for
example, in the context of sizeof).  However, they definitely do
NOT have to have the same representation.  For example, in a C
interpreter they could contain tag information that could be used to
distinguish between them (presumably to detect usage errors).