Path: utzoo!attcan!uunet!cbmvax!daveh
From: daveh@cbmvax.UUCP (Dave Haynie)
Newsgroups: comp.lang.c++
Subject: Virtual Destructors?
Message-ID: <5568@cbmvax.UUCP>
Date: 22 Dec 88 23:53:57 GMT
Organization: Commodore Technology, West Chester, PA
Lines: 46

I'm pretty new to this C++ game, but I've already run into something that
doesn't make sense.  Perhaps this is already fixed -- I'm using Lattice 
C++ V1.00 on the Amiga, which is based on cfront V1.1a.  In any case, I
can't figure out why in the world destructors aren't virtual.  Basically,
I have this situation that looks pretty much like the following:

	class A {
		...
		A(..) {...}
		~A( ) {...}
		...
	};

	class B : public A {
		...
		B(..) : (...) {...}
		~B( ) {...}
		...
	};

	... // Much later
	
	A tool;

	if (thing)
           tool = new A(...);
	else
	   tool = new B(...);

	... // Yet again even later

	delete tool;

No problem, except that when I delete tool, I always get A's destructor,
not B's.  Certainly I can take care of this problem by having each 
destructor call a virtual function which does the actual destroying, but
I can't think of any good reason for destructors to not be virtual.  Is
this really a problem, or am I missing something really obvious?




-- 
Dave Haynie  "The 32 Bit Guy"     Commodore-Amiga  "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: D-DAVE H     BIX: hazy
              Amiga -- It's not just a job, it's an obsession