Path: utzoo!news-server.csri.toronto.edu!rutgers!cbmvax!uunet!tdatirv!sarima
From: sarima@tdatirv.UUCP (Stanley Friesen)
Newsgroups: comp.lang.c
Subject: Re: What's an LValue [was A quick question]
Message-ID: <175@tdatirv.UUCP>
Date: 14 Mar 91 16:16:39 GMT
References: <1991Mar12.030759.26698@nntp-server.caltech.edu> <31306@shamash.cdc.com> <1991Mar13.050555.26149@tandem.com>
Reply-To: sarima@tdatirv.UUCP (Stanley Friesen)
Organization: Teradata Corp., Irvine
Lines: 27

In article <1991Mar13.050555.26149@tandem.com> jimbo@tandem.com (Jim Lyon) writes:
<In article <31306@shamash.cdc.com> bls@u02.svl.cdc.com (Brian Scearce) writes:
<>0. variable names (excepting function, array and enum constant
<>   names) are lvalues.
<>1. e[k] is an lvalue, regardless of whether e and k are lvalues.
<>2. (e) is an lvalue iff e is.
<>3. e.name is an lvalue iff e is.
<>4. e->name is an lvalue regardless of whether e is an lvalue.
<>5. *e is an lvalue regardless of whether e is an lvalue.
<
<Rules (1) and (5) need to be further qualified.  e[k] and *e are
<lvalues regardless of whether e and k are lvalues, UNLESS the type
<of e[k] or *e is either Array... or Function...

Well, as I understand the ANSI definition of lvalue (different than the
K&R1 definition), the original rules are correct as stated.  It is just
that in that case the result is not a *modifiable* lvalue, and is converted
in all value contexts into a pointer to the object.

<For example, if A is declared as "int A[10][10]", then "A[5]"
<is not an lvalue, because the type of "A[5]" is "Array of int".

Or rather, by ANSI definitions, it *is* an lvalue that is immediately
converted into a non-lvalue pointer of type "Pointer to int".
-- 
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uunet!tdatirv!sarima				(Stanley Friesen)