[boost] Construct weak_ptr from intrusive_ptr?

From: Hickman, Greg (greg.hickman_at_[hidden])
Date: 2002-12-09 14:56:32

I notice that a shared_ptr can be constructed directly from an
intrusive_ptr, but a weak_ptr cannot.  Is there some reason why we wouldn't
want to add the appropriate constructor to weak_ptr?

-Greg Hickman