Path: utzoo!mnetor!uunet!husc6!yale!cmcl2!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: comp.lang.c
Subject: Re: Dereferencing zero
Message-ID: <7063@brl-smoke.ARPA>
Date: 13 Jan 88 05:39:33 GMT
References: <3306@ihlpf.ATT.COM> <7010@brl-smoke.ARPA> <1561@rtech.UUCP> <2953@zeus.TEK.COM>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 12

In article <2953@zeus.TEK.COM> dant@tekla.UUCP (Dan Tilque) writes:
>	struct system_vectors	*svp;
>	svp = 0;
>	(svp->whatever_vector)();

If you really have to do something like this, odds are your compiler
will support it.  However, be aware that you have really, according
to the proposed C standard, made `svp' a null pointer by the assignment,
and an implementation may represent null pointers specially.  There are
many reasons for that that I don't want to get into.  Just remember that
the C standard does not guarantee that you can ever use 0 as the address
of an object (quite the contrary), but some implementations may permit it.