Xref: utzoo comp.lang.c:8428 comp.unix.questions:6173
Path: utzoo!mnetor!uunet!husc6!cmcl2!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: comp.lang.c,comp.unix.questions
Subject: Re: BSD C compiler bug
Message-ID: <7519@brl-smoke.ARPA>
Date: 22 Mar 88 18:49:39 GMT
References: <570@mtxinu.UUCP> <10747@mimsy.UUCP> <7507@brl-smoke.ARPA> <10754@mimsy.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 10

In article <10754@mimsy.UUCP> chris@mimsy.UUCP (Chris Torek) writes:
>Constant expressions have *everything* to do with it!

Ok, I see now.  The relevant factor is that integer-to-pointer
conversion does not occur automatically for assignment, except
in the case that the RHS is a null pointer constant, and as
you correctly observer, (0,0) is not a valid null pointer constant,
because the comma operator is not allowed in constant expressions
(except within the operand of sizeof).  I'm not sure why that
constraint was imposed; it doesn't seem necessary.