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From: chris@mimsy.umd.edu (Chris Torek)
Newsgroups: comp.lang.c
Subject: Re: sizeof a struc field
Message-ID: <20369@mimsy.umd.edu>
Date: 24 Oct 89 18:35:41 GMT
References: <7710@microsoft.UUCP> <11316@smoke.BRL.MIL> <7685@cdis-1.uucp> <1423@crdos1.crd.ge.COM>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 20

>In article <2488@munnari.oz.au> ok@cs.mu.oz.au (Richard O'Keefe) writes:
>>... isn't the actual restriction that the argument of "sizeof" must be
>>an L-value in ANSI C? ... ((struct foo*)NULL)->field is not an L-value.

In article <1423@crdos1.crd.ge.COM> davidsen@crdos1.crd.ge.COM
(Wm E Davidsen Jr) writes:
>The standard says that you may take the sizeof an array, so the
>expression most definitely does not have to be an lvalue. You can also
>take sizeof something const.

According to the standard, arrays and consts are `non modifiable
lvalue's (which rather contradicts the original meaning of l-value!).

Anyway, I happen to think that `sizeof(*(type *)junk)' and similar
constructs ought to be acceptable for any parse-able, cast-able `junk'.
The standard happens to disagree.  This is Just One Of Those Things.
-- 
`They were supposed to be green.'
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@cs.umd.edu	Path:	uunet!mimsy!chris