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From: mccaugh@uiucdcsb.UUCP
Newsgroups: comp.lang.c
Subject: Re: structure enhancements
Message-ID: <165600018@uiucdcsb>
Date: Wed, 28-Oct-87 01:08:00 EST
Article-I.D.: uiucdcsb.165600018
Posted: Wed Oct 28 01:08:00 1987
Date-Received: Sat, 31-Oct-87 01:54:34 EST
References: <444@root44.co.uk>
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Nf-From: uiucdcsb.cs.uiuc.edu!mccaugh    Oct 28 00:08:00 1987


 This may not be possible. -> is the "indirect component selector" (recall '.'
 is the "direct" one) and according to Harbison & Steele, page 149: "The value
 (of an indirect component selection expression) is the named member of the
 union or structure and (so) is an LVALUE." But on page 184 appears the warn-
 ing that "the result of an assignment expression is NEVER an lvalue." (See
 also page 186.) We are speaking here of "compound" assignment expressions.
 Thus p -> n  must be an lvalue ("namely", n) while p ->= n cannot be. Again,
 if this is confusing, please read page 186 of H&S which admonishes that the
 resulting value stored in the left operand of a compound assignment (such as 
 p -> n in p ->= n) can NOT be an lvalue, which p -> n itself definitely is.

 mccaugh @ uiucmsl