Path: utzoo!yunexus!geac!syntron!jtsv16!uunet!ncrlnk!ncr-sd!hp-sdd!ucsdhub!ucsd!rutgers!att!ihlpl!knudsen
From: knudsen@ihlpl.ATT.COM (Knudsen)
Newsgroups: comp.lang.c
Subject: Re: Efficient coding considered harmful?
Summary: Why not portable?
Message-ID: <7421@ihlpl.ATT.COM>
Date: 28 Oct 88 18:17:03 GMT
Article-I.D.: ihlpl.7421
References: <3105@hubcap.UUCP> <34112@XAIT.XEROX.COM> <1700@dataio.Data-IO.COM> <8775@smoke.BRL.MIL>
Organization: AT&T Bell Laboratories - Naperville, Illinois
Lines: 14

In article <8775@smoke.BRL.MIL>, gwyn@smoke.BRL.MIL (Doug Gwyn ) writes:
> (But don't write something like
> 	for (p = &a[j]; --p >= a; )
> which is nonportable.)

Why not portable?  I know there are some weird architectures that
may treat pointers strangely.  But assuming that p is declared apointer
to the same type as a[], don't the official semantics of C
guarantee that the above code is valid?
What am I missing?
-- 
Mike Knudsen  Bell Labs(AT&T)   att!ihlpl!knudsen
"Lawyers are like nuclear bombs and PClones.  Nobody likes them,
but the other guy's got one, so I better get one too."