[C++-sig] Question regarding protected destructor

[David Abrahams]

From: "gideon may" <gideon at computer.org>

> Unfortunately I'm unable to change the code, it's a library which is in
> constant
> flux. All the class(es) destructors are protected since it has it's own
> reference
> counting and memory management.

Oh! in that case...

> I looked into the HeldType but I'm not sure
> it is of any help to me.

Yes, it should be! You need to make a smart pointer class (template) which
you can use as HeldType.

> The classes I would like to use with boost are part
> of
> a large class hierarchy, each of them derived from a base class with the
> protected destructor. The library which I am trying to wrap is the
> OpenSceneGraph (http://www.openscenegraph.org/).

If you supply a smart pointer template, say, "scene_graph_ptr<T>", which
does the reference-counting, you can pass that as HeldType. The only other
requirement is that you supply a nested typedef in your smart pointer:

    typedef T element_type;

so that pointee<T> knows what type it's pointing at.

Now you can wrap functions which accept T cv*, T cv&, and
scene_graph_ptr<T> arguments.

HTH,
Dave