Xref: utzoo comp.arch:4878 comp.lang.c:10205
Path: utzoo!attcan!uunet!husc6!mailrus!nrl-cmf!ames!umd5!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: comp.arch,comp.lang.c
Subject: Re: negative addresses
Message-ID: <7916@brl-smoke.ARPA>
Date: 18 May 88 14:25:45 GMT
References: <2393@uvacs.CS.VIRGINIA.EDU> <21541@amdcad.AMD.COM> <1988May12.162906.16901@utzoo.uucp> <7881@brl-smoke.ARPA> <10001@tekecs.TEK.COM>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 14

In article <10001@tekecs.TEK.COM> andrew@frip.gwd.tek.com (Andrew Klossner) writes:
-Doug Gwyn (gwyn@brl-smoke.ARPA) writes:
->> Unfortunately, it is a real problem, because there are zillions of
->> programs that implicitly assume that [null] pointers are all-zeros.
-> I don't think this is true.  How about an example?
-		if (tbuf->c_ptr)
-		if (tbuf->c_ptr == NULL)
-		if (tp->t_rbuf.c_ptr) {
-		if (tp->t_tbuf.c_ptr) {

None of these are non-portable uses of C; none of them depend on
null pointers being represented by all-zero data.

I'm still waiting for an example...