namespace boost {
  namespace dataflow {
    namespace utility {
      template<typename Signature, typename T> 
        boost::function< Signature > 
        bind_mem_fn_overload(typename dataflow::utility::slot_type< Signature, T >::type, 
                             T &);
      template<typename Signature, typename T> 
        boost::function< Signature > 
        bind_mem_fn_const_overload(typename dataflow::utility::slot_type< Signature, const T >::type, 
                                   T &);
    }
  }
}