Im very new to boost, and have just started to intergrate the shared_ptr smart pointer into one of my applications. I am storing a lot of pointers (to objects) in a std::vector. typedef boost::shared_ptr<CMyClass> my_shared_ptr; typedef std::vector<my_shared_ptr> my_shared_ptr_vector; What i need to do is to additionally store a reference to the same objects (in the vector) in a CListCtrl (MFC). The CListCtrl allows you to associate a pointer with each item (row) in the list control. Before i used shared_ptr i used to add the data as below: CMyClass pItem = new CMyClass(); my_vector->push_back(pItem); CListCtrl::SetItemData->SetItemData(iItemNumber, (DWORD)pItem); Now using shared_ptr (see below) i get a compiler error saying that it cannot convert from my_shared_ptr to DWORD. my_shared_ptr myPtr (new CMyClass(); my_shared_ptr_vector->push_back(myPtr); CListCtrl::SetItemData->SetItemData(iItemNumber, reinterpret_cast<DWORD_PTR>(myPtr)); My second question is if i was able to add the item data as ... CListCtrl::SetItemData->SetItemData(iItemNumber, reinterpret_cast<DWORD_PTR>(myPtr)); ...would the internal reference counter be incremented in shared_ptr? My vector may be destroyed before my CListCtrl and I dont want the item data to be deleted until both are out of scope. Thanks Andy