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From: jordan@aerospace.aero.org (Larry M. Jordan)
Newsgroups: comp.lang.c++
Subject: Calling virtual functions INDIRECTLY from constructors
Message-ID: <94876@aerospace.AERO.ORG>
Date: 18 Dec 90 20:58:33 GMT
Sender: news@aerospace.aero.org
Reply-To: jordan@antares.UUCP (Larry M. Jordan)
Organization: The Aerospace Corporation, El Segundo, CA
Lines: 50

Should there also be a loss of "virtualness" when virtual
member functions are called INDIRECTLY from a constructor?  


Consider the following:

#include <stdio.h>

static void say(char *s) { printf("%s\n", s); }


struct C0 {
	virtual void f() { say("C0 init"); }
	virtual void g() { f(); }
	C0() { g(); }
};

struct C1 : C0 {
	virtual void f() { say("C1 init"); }
	virtual void g() { f(); }
	C1() { g(); }
};


main()
{
	C0 aC0;
	C1 aC1;
}




I was expecting:

	C0 init
	C1 init
	C1 init

But got (from Zortech v2.1):

	C0 init
	C0 init
	C1 init


This seems like an amazing sleight of hand.  How do you suppose it's done?


-- Larry Jordan