Although I have been using shared_ptr's for a while, I still get a bit confused with polymorphic stuff ...no change there. An pseudocode example: Class A { }; Class B : public A { DoStuff1(); DoStuff2(); DoStuff3(); DoStuff4() }; // MyFunction handles A and classes derived from A MyFunction(shared_ptr<A>) { }; Main() { shared_ptr<A> poly<new B); // OK so far MyFunction(poly); // Still OK - // OK, done this, but now if I want to call a load of stuff in an instance of B // I either have to make a load of pointer casts (because poly is an A) dynamic_pointer_cast<B>(poly)->DoStuff1(); dynamic_pointer_cast<B>(poly)->DoStuff2(); dynamic_pointer_cast<B>(poly)->DoStuff3(); dynamic_pointer_cast<B>(poly)->DoStuff4(); // Or this? shared_ptr<B> tmp = dynamic_pointer_cast<B>(poly); // is this right? // I have to create a new pointer? tmp->DoStuff1(); tmp->DoStuff2(); tmp->DoStuff3(); tmp->DoStuff4(); } So, the quesiton is one of efficiency - if I was using pointers, I would just new a B and assign to a B* variable, then pass in to the function which would use it as an A - no temp required. With above a new tmp pointer seems to be required - am I right or have I missed something blindingly obvious. James This message (including any attachments) contains confidential and/or proprietary information intended only for the addressee. Any unauthorized disclosure, copying, distribution or reliance on the contents of this information is strictly prohibited and may constitute a violation of law. If you are not the intended recipient, please notify the sender immediately by responding to this e-mail, and delete the message from your system. If you have any questions about this e-mail please notify the sender immediately.