ensure_started

Vladimir Sekissov <>
Mon Mar 24 16:12:18 CET 2003


Good day,


cpressey> I guess the lesson to take from this is that it's good coding style to
cpressey> always use a finite timeout when waiting for a reply from something you're
cpressey> not linked to, because that reply simply may never show up no matter how
cpressey> carefully you code the server... ?

I usually use erlang:monitor/2 in such cases. You don't need to use
timeout with it if you shure that process can only answer or die (no
hungs). Small example from code I use with mdisp:

%% We are implementing synchronous call to mdisp process,
%% it answers with its Pid and after with actual Result

disp_call(Name, Key, Args) ->
  mdisp_tt:send(Name, Key, {self(), continue, Args}),
  rec_answer(Key).

rec_answer(Key) ->
  receive
    {Key, iam, Pid} ->
      Ref = erlang:monitor(process, Pid),
      receive
	{'DOWN', Ref, _, _, Reson} ->
	  exit(Reson);
	{Key, Answer} ->
	  erlang:demonitor(Ref),
	  Answer
      end
  after 500 ->
      {error, {nothread, Key}}
  end.

Best Regards,
Vladimir Sekissov



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