namespace boost {
  namespace dataflow {
    namespace utility {
      template<typename MemFn, typename T> 
        boost::function< typename member_function_signature< MemFn >::type > 
        bind_mem_fn(MemFn, T &);
      template<typename MemFn, typename T> 
        boost::function< typename member_function_signature< MemFn >::type > 
        bind_mem_fn_flexible(MemFn, const T &);
    }
  }
}