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From: chris@mimsy.umd.edu (Chris Torek)
Newsgroups: comp.lang.c
Subject: Re: Array bounds checking with C????
Message-ID: <26216@mimsy.umd.edu>
Date: 27 Aug 90 10:39:09 GMT
References: <7611@ucdavis.ucdavis.edu> <26196@mimsy.umd.edu> <619.26d6cfb2@iccgcc.decnet.ab.com>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 19

In article <26196@mimsy.umd.edu> I wrote:
>>... it still objected to `&arr[sizeof arr/sizeof *arr]',
>>which is Officially Legal.

In article <619.26d6cfb2@iccgcc.decnet.ab.co> browns@iccgcc.decnet.ab.com
(Stan Brown, Oak Road Systems) writes:
>Just to stick in my $.02:
>
>int arr[4];
>
>sizeof arr/sizeof *arr is 4, so &arr[4] may not be legal.  Whether legal or
>not, the address is certainly outside the array.

See ANSI standard X3.159-1989, section 3.3.6, `additive operators'.
(I might have included this before but I was at home.)  As I said, it
is Officially Legal.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 405 2750)
Domain:	chris@cs.umd.edu	Path:	uunet!mimsy!chris