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From: karl@haddock.ISC.COM (Karl Heuer)
Newsgroups: comp.lang.c
Subject: Re: char (*a)[]  (was: Style [++i vs i++])
Message-ID: <931@haddock.ISC.COM>
Date: Wed, 12-Aug-87 17:30:17 EDT
Article-I.D.: haddock.931
Posted: Wed Aug 12 17:30:17 1987
Date-Received: Sat, 15-Aug-87 02:23:21 EDT
References: <8298@brl-adm.ARPA> <587@cblpe.ATT.COM> <189@xyzzy.UUCP> <1987Aug10.192923.7879@sq.uucp>
Reply-To: karl@haddock.ima.isc.com (Karl Heuer)
Organization: Interactive Systems, Boston
Lines: 14
Summary: NULL+1 is illegal

In article <1987Aug10.192923.7879@sq.uucp> msb@sq.UUCP (Mark Brader) writes:
>Wayne Throop writes:
>>... but *also* because it performs arithmetic on a null pointer, and
>>of course, this is illegal.)
>
>Um, I don't think so, Wayne; it's just that the result, if you indirect
>through such a pointer, is undefined.  K&R is silent on this, but ANSI
>3.3.6 seems pretty clear.

"A.6.2 Undefined behavior: ... A pointer that is not to a member of an array
object is added to or subtracted from" [Oct86 dpANS].  A null pointer is an
extreme example of this.

Karl W. Z. Heuer (ima!haddock!karl or karl@haddock.isc.com), The Walking Lint