Path: utzoo!mnetor!uunet!husc6!cmcl2!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: comp.lang.c
Subject: Re: `noalias' vs `register'
Message-ID: <6868@brl-smoke.ARPA>
Date: 18 Dec 87 22:37:48 GMT
References: <9817@mimsy.UUCP> <47000026@uxe.cso.uiuc.edu>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 17

In article <47000026@uxe.cso.uiuc.edu> mcdonald@uxe.cso.uiuc.edu writes:
>      int *xxxx;
>                int r;
>                xxxx = &r;
>What would happen if I had said " noalias int r" ? From what has been said,
>I have no earthly idea. ( Is it an error? If the compiler could recognize it
>as an error, why have it?)

About the only error concerning "noalias" you would ever be likely to
get would be an attempt to assign a pointer to noalias object into a
pointer to plain object without using an explicit cast.  (This may
manifest itself as a function parameter type mismatch also.)  The
other direction is legal and safe.

You can always take the address of a noalias object with &, obtaining
a pointer to noalias object thereby; it would be the attempt to assign
the pointer to a pointer to plain object that would generate the error.