Re: [boost] Re: shared_ptr: unsafe, or am I crazy?

From: Larry Evans (jcampbell3_at_[hidden])
Date: 2002-01-21 10:05:00

David Abrahams wrote:

> ----- Original Message -----
> From: "Larry Evans" <jcampbell3_at_[hidden]>
>
> > Now, about counted_base.  Since one of the purposes of counted_base is to
> > overcome the lack of virtual DTOR, could John Maddox's is_polymorphic<>
> > trait be used to provide a specialized version of counted_base_impl
> without the
> > extra D del pointer?
>
> struct A {};
> struct B { virtual ~B(); };
>
> shared_ptr<B> x(new B());
> shared_ptr<A> y(x); // <--- what happens here?
>
> struct C { virtual void f(); }
> struct D : C { };
>
> shared_ptr<D> d(new D);
> shared_ptr<C> c(d); // <--- or here?

Your examples make it clear to me that the del pointer
can't be avoided.

Thanks.