Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!husc6!cmcl2!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: comp.lang.c,comp.unix.wizards
Subject: Re: pointer alignment when int != char *
Message-ID: <6357@brl-smoke.ARPA>
Date: Sat, 29-Aug-87 04:03:03 EDT
Article-I.D.: brl-smok.6357
Posted: Sat Aug 29 04:03:03 1987
Date-Received: Sun, 30-Aug-87 07:40:52 EDT
References: <493@its63b.ed.ac.uk> <6061@brl-smoke.ARPA> <3812@spool.WISC.EDU> <2130@umn-cs.UUCP>
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 15
Xref: mnetor comp.lang.c:4019 comp.unix.wizards:3968

In article <2130@umn-cs.UUCP>, randy@umn-cs.UUCP (Randy Orrison) writes:
> In article <483@mtxinu.UUCP> ed@mtxinu.UUCP (Ed Gould) writes:
> >Pointers may be subtracted *only* if they point to members of the same
> >array of elements.
> How is this determined?  example:
> strlen(s)
> 	return (c-s);

Obviously all characters in a string are in the same object (be it
(char []) or chunk of malloc()-allocated storage.  I don't recall if
the latter is covered by the draft proposed standard but it should be.

If some code violates the same-aggregate pointer constraint, the
behavior is unspecified.  It might work or it might not.  No portable
program should violate the constraint.