# File lib/core/selectable.rb, line 82
    def fileno(fd = DEFAULT)
      if fd == DEFAULT
        Cproton.pn_selectable_get_fd(@impl)
      elsif fd.nil?
        Cproton.pn_selectable_set_fd(@impl, Cproton::PN_INVALID_SOCKET)
      else
        Cproton.pn_selectable_set_fd(@impl, fd)
      end
    end