[erlang-questions] Can not kill the registered process

[Felix Gallo]

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
>
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