Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!deb
From: deb@svax.cs.cornell.edu (David Baraff)
Newsgroups: comp.lang.c++
Subject: Lvalue checking for operator= ??
Message-ID: <33433@cornell.UUCP>
Date: 21 Oct 89 20:17:21 GMT
Sender: nobody@cornell.UUCP
Reply-To: deb@svax.cs.cornell.edu (David Baraff)
Organization: Cornell Univ. CS Dept, Ithaca NY
Lines: 19

Suppose you have a standard matrix class, which implements '+',
and also has its own assignment operator defined i.e.

	matrix &matrix::operator= (matrix &m)

exists. Then,

	matrix	a, b, c;

		...

	a+b = c;

appears to be legal. (As least it compiled under 1.2.) Is it legal under
2.0 ? What does it really mean? Shouldn't  the '=' operator be forced
to only accept an lvalue as its left-hand operand?

	David Baraff
	deb@svax.cs.cornell.edu