anchor.diff:      
   
   %% "Beates" the heart once.
  -send_heart_beat(#state{port=Port, callback=Cb}) ->
  +send_heart_beat(#state{port=Port, callback=Cb, options=Opts}) ->
  +    ok = check_system(Opts),
       ok = check_callback(Cb),
       Port ! {self(), {command, [?HEART_BEAT]}}.
   
  
positive.code: 	{'EXIT', Port, Reason} when Reason =/= badsig ->
  	    exit(normal)
      end.
  
  do_cycle_port_program(Caller, Parent, #state{port=Port} = S) ->
      unregister(?HEART_PORT_NAME),
  
negative.code:     case catch start_portprogram() of
  	{ok, Port} ->
  	    Starter ! {ok, self()},
  	    loop(Parent, #state{port=Port, cmd=[], options=[]});
  	no_heart ->
  	    Starter ! {no_heart, self()};
  	error ->
  