[erlang-questions] Can not kill the registered process

[Harit Himanshu]

and as per your suggestion Felix, I tried exit/2 as well, which seems to
work pretty well

1> c(error_handling).

{ok,error_handling}

2> error_handling:monitor_runner().

started new process <0.40.0> and reference #Ref<0.0.0.77>.

<0.39.0>

I am running.

I am running.

3> exit(whereis(runner), kill).

runner got killed, restarting.

started new process <0.43.0> and reference #Ref<0.0.0.87>.

true

I am running.

I am running.

4> exit(whereis(runner), kill).

runner got killed, restarting.

started new process <0.46.0> and reference #Ref<0.0.0.96>.

true

I am running.

I am running.

I am running.

I am running.

I am running.

I am running.

I am running.

I am running.

I am running.

5>

I am running.

I am running.

5> exit(whereis(runner), "kill you runner").

runner got killed, restarting.

started new process <0.49.0> and reference #Ref<0.0.0.114>.

true

I am running.

I am running.

Thank you for your help
+ Harit Himanshu

On Tue, Jan 13, 2015 at 2:33 PM, Harit Himanshu <
harit.subscriptions@REDACTED> wrote:

> you are right Felix, exit/1 did not help.
>
> Instead I tried timer:kill_after() and this seems to work as expected. I
> made no changes to code, only changed how to kill the registered process
> and it started to work
>
>
> 1> c(error_handling).
>
> {ok,error_handling}
>
> 2> error_handling:monitor_runner().
>
> started new process <0.40.0> and reference #Ref<0.0.0.77>.
>
> <0.39.0>
>
> I am running.
>
> I am running.
>
> I am running.
>
> I am running.
>
> 3> timer:kill_after(3000, whereis(runner)).
>
> {ok,{1421188290386972,#Ref<0.0.0.88>}}
>
> I am running.
>
> runner got killed, restarting.
>
> started new process <0.45.0> and reference #Ref<0.0.0.95>.
>
> I am running.
>
> I am running.
>
> I am running.
>
> 4> timer:kill_after(3000, whereis(runner)).
>
> {ok,{1421188310002128,#Ref<0.0.0.101>}}
>
> runner got killed, restarting.
>
> started new process <0.48.0> and reference #Ref<0.0.0.107>.
>
> I am running.
>
> I am running.
>
> 5>
>
> Thank you
> + Harit Himanshu
>
> On Tue, Jan 13, 2015 at 2:31 PM, Felix Gallo <felixgallo@REDACTED> wrote:
>
>> exit/1 doesn't do what you think it does.  Maybe try exit/2?
>>
>> On Tue, Jan 13, 2015 at 2:23 PM, Harit Himanshu <
>> harit.subscriptions@REDACTED> wrote:
>>
>>> The problem I am trying while learning from exercises from Joe's book is
>>>
>>> Write a function that creates a registered process that writes out "I’m
>>> still running" every five seconds. Write a function that monitors this
>>> process and restarts it if it dies. Start the global process and the
>>> monitor process. Kill the global process and check that it has been
>>> restarted by the monitor process.
>>>
>>> So I created the runner and monitor_runner as
>>>
>>> runner() ->
>>>   receive
>>>   after 5 * 1000 ->
>>>     io:format("I am running.~n"),
>>>     runner()
>>>   end.
>>>
>>> monitor_runner() ->
>>>   spawn(fun() ->
>>>     {Pid, Ref} = spawn_monitor(error_handling, runner, []),
>>>     io:format("started new process ~p and reference ~p.~n", [Pid, Ref]),
>>>     register(runner, Pid),
>>>     receive
>>>       {'DOWN', Ref, process, Pid, _Why} ->
>>>         io:format("runner got killed, restarting"),
>>>         monitor_runner();
>>>       X -> X
>>>     end
>>>   end).
>>>
>>>
>>> When I run this, I get
>>>
>>> 1> c(error_handling).
>>>
>>> {ok,error_handling}
>>>
>>> 2> Pid = error_handling:monitor_runner().
>>>
>>> started new process <0.40.0> and reference #Ref<0.0.0.77>.
>>>
>>> <0.39.0>
>>>
>>> I am running.
>>>
>>> 3>
>>>
>>> 3>
>>>
>>> I am running.
>>>
>>> 3> Pid.
>>>
>>> <0.39.0>
>>>
>>> I am running.
>>>
>>> I am running.
>>>
>>> I am running.
>>>
>>> I am running.
>>>
>>> I am running.
>>>
>>> 4> whereis(runner).
>>>
>>> <0.40.0>
>>>
>>> I am running.
>>>
>>> 6> exit(whereis(runner)).
>>>
>>> ** exception exit: <0.40.0>
>>>
>>> I am running.
>>>
>>> I am running.
>>>
>>> I am running.
>>>
>>> I am running.
>>>
>>> I am running.
>>>
>>> I am running.
>>>
>>> I am running.
>>>
>>> 7>
>>>
>>> *Problem?*
>>>  The runner is still running.
>>> 1.) Why is the process not getting killed?
>>> 2.) Why is it not caught by {'DOWN'....}
>>>
>>> What am I missing here?
>>>
>>> Thanks
>>> + Harit
>>>
>>> _______________________________________________
>>> erlang-questions mailing list
>>> erlang-questions@REDACTED
>>> http://erlang.org/mailman/listinfo/erlang-questions
>>>
>>>
>>
>
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