casting shared_ptr while preserving use_count..

From: John Liberty (libertyj_at_[hidden])
Date: 2001-11-09 01:26:49

I'd like to essentially downcast (to derived) from a base class with 
virtual methods while preserving (and incrementing) the use_count..

for an upcast, I can simply assign a shared_ptr<Child> to 
shared_ptr<Parent>. But for the downcast, I need to incorporate a 
dynamic_cast<childType> to get what I want..

With an older compiler that didn't like member templates, the boost 
conf would leave the internal pointer and use count as public, so I 
wrote my own casting function.. 
However, the newer compiler doesn't give this public access, so I may 
be stuck without modifying the header...

any thoughts?