Path: utzoo!attcan!uunet!microsoft!jimad
From: jimad@microsoft.UUCP (Jim ADCOCK)
Newsgroups: comp.lang.c++
Subject: Re: Copying objects
Message-ID: <55612@microsoft.UUCP>
Date: 3 Jul 90 17:15:57 GMT
References: <18753@well.sf.ca.us> <4853@darkstar.ucsc.edu>
Reply-To: jimad@microsoft.UUCP (Jim ADCOCK)
Distribution: comp
Organization: Microsoft Corp., Redmond WA
Lines: 41

In article <4853@darkstar.ucsc.edu> ericg@ucschu.ucsc.edu (Eric Goodman) writes:
>A virtual overloaded operator= should work (I'm assuming that virtual 
>operators are legal); 

Virtual overloaded operators are legal -- except operators new and delete.
This is all neatly summerized in a table on page 306 of ARM.

Interestingly, operator= has the unique characteristic of being
virtual but not inherited!  Can someone explain what this is suppose
to mean? -- When I try the example below on my local compilers, it appears
that virtual B& B::operator=(const B&) *is* being inherited. ???

extern "C"
{
#include "stdio.h"
}

class B
{
public:
	virtual B& operator=(const B&);
};
B& B::operator=(const B&) 
{ static int i=0; printf("%lX B::op=\n", (long)&i); return *this; }

class D : public B
{
public:
	int i;
};

main()
{
	B& b1 = *new B;
	B& b2 = *new B;
	D& d1 = *new D;
	D& d2 = *new D;
	b1 = b1;
	d1 = d2;
	b1 = d1;
}