namespace boost {
  namespace signals {
    template<typename Signature, typename T> struct slot_selector;

    template<typename Signature, typename T> 
      struct is_component<slot_selector< Signature, T >>;
    template<typename Signature, typename T> 
      struct get_signal<slot_selector< Signature, T >>;
    template<typename Signature, typename T> 
      struct get_signal_type<slot_selector< Signature, T >>;
    template<typename Signature, typename T> 
      struct get_slot<Signature, slot_selector< Signature, T >>;

    // Allows arbitrary member functions to serve as slots. 
    template<typename Signature, typename T> 
      slot_selector< Signature, T > 
      make_slot_selector(unspecified func, T & object);
  }
}