Question

I want to put any kind of Object (Object, Object etc.) into one shared_ptr. So I created base class and use shared_ptr.

But, how can I declare

T getMember();

within the base class so I can call ObjectBase.getMember?

class ObjectBase
{
public:
  //virtual getMember HOWTO?
};

template<typename T>
class Object : public ObjectBase
{
public:
  Object(T x):member(x) { }
  T getMember() { return member; }

private:
  T member;
};

Answer 1

You can’t. How should such a declaration look, that it can return all kinds of types? It’s just not possible. You’d have to cast the ObjectBase* to the correct Object<T>* and then use the getMember function. It’s only possible if all T share a common base class, so you could return a pointer to that. But that would put a strict constraint on T.