Hello all,I'm trying to use ptr_set with my class Hierarchy.Base is an abstract base class with a bunch of pure virtual functions.I've some derived classes with those virtual functions defined in them.I'm using this Base class hierarchy in another class (say Other).So I've declared a member variable of Other asptr_set<Base> m_items ;this works fine on linux with gcc-4.2 but with VS2005, I'm getting a compilation error, saying that It cannot instantiate base class as it is having pure virtual functions.Am I doing some thing wrong here ?Surya