Path: utzoo!mnetor!uunet!mcvax!ruuinf!piet
From: piet@ruuinf.UUCP (Piet van Oostrum)
Newsgroups: comp.lang.pascal
Subject: Re:  Global variables
Message-ID: <412@ruuinf.UUCP>
Date: 18 Apr 88 14:22:10 GMT
References: <12654@brl-adm.ARPA> <529@taux01.UUCP> <4770@aw.sei.cmu.edu> <277@csvax.liv.ac.uk>
Organization: Univ of Utrecht, Dept of CS
Lines: 16
In-reply-to: sqkeith@csvax.liv.ac.uk's message of 13 Apr 88 19:32:34 GMT

Posting-Front-End: GNU Emacs 18.47.9 of Mon Mar 21 1988 on ruuinf (hcx/ux)



In article <4770@aw.sei.cmu.edu>, firth@sei.cmu.edu (Robert Firth) writes:
>
> I don't think that's right.  For example, in Pascal, an explicit
> pointer (^Thing) cannot point anywhere except into the heap, ie
> at an object created by NEW.  It cannot alias any global variable.
> 
> That leaves only VAR parameters as potential aliases.  Even here,
> a VAR parameter of one type (VAR p: ThingA) cannot alias a global
> variable of any other type (VAR g: ThingB).

It can if one is a part (field, or array element) of the other.
-- 
Piet van Oostrum, Dept of Computer Science, University of Utrecht
Budapestlaan 6, P.O. Box 80.012, 3508 TA Utrecht, The Netherlands
Telephone: +31-30-531806              UUCP: ...!mcvax!ruuinf!piet