[erlang-patches] run_erl: propagate exit status

Sverker Eriksson <>
Tue Feb 4 18:45:54 CET 2014


Magnus ! ping.

Any interest in trying to get this two year old patch into OTP 17?

The feature of propagating exit status seems reasonable and useful.

/Sverker, Erlang/OTP


On 11/29/2011 05:19 PM, Sverker Eriksson wrote:
> Henrik:
>
> This  one should replace the current mh/run_erl-exit-status in pu:
>
> git fetch git://github.com/legoscia/otp.git run_erl_exit_status_simple
>
>
> Magnus:
>
> I got two objections on the the other version using select timeout.
>
> 1. You don't check if it actually was a timeout from select() before 
> doing "want_to_exit = 1".
> 2. No test that reproduces the more complicated case.
>
> /Sverker
>
>
> Magnus Henoch wrote:
>> Good catch, exit() is indeed not safe inside a signal handler, as it
>> flushes stdio buffers etc.
>>
>> I committed a new version that uses a select timeout:
>>
>> git fetch git://github.com/legoscia/otp.git run_erl_exit_status
>> https://github.com/legoscia/otp/commit/run_erl_exit_status
>>
>> But since I still haven't been able to reproduce the case that the
>> alarm is supposed to handle, I also committed a simpler change
>> that leaves the alarm signal as it used to be:
>>
>> git fetch git://github.com/legoscia/otp.git run_erl_exit_status_simple
>> https://github.com/legoscia/otp/commit/run_erl_exit_status_simple
>>
>> That change still gives the correct result with all invocations I've
>> tried.  It might be a safer bet...
>>
>> Regards,
>> Magnus
>>
>> ----- Original Message -----
>>> Patch review:
>>>
>>> Is it really right to call exit() from a signal handler like that.
>>> Wouldn't it be safer to use the select() timeout instead of alarm().
>>>
>>> Sorry for the late review, code stop is tomorrow for R15B.
>>>
>>> /Sverker, Erlang/OTP
>>>
>>>
>>> Magnus Henoch wrote:
>>>> Hi all,
>>>>
>>>> Here is a patch that makes run_erl return the exit status of its
>>>> child
>>>> process.  (Probably only useful when using run_erl without -daemon,
>>>> just for convenient logging.)
>>>>
>>>> I added a signal handler for SIGALRM, since that appeared to be one
>>>> of
>>>> the ways run_erl exits, but I haven't been able to trigger that in
>>>> my
>>>> testing (it always exits because it can't read from the child's
>>>> pty).
>>>> I would appreciate informed opinions about whether that part is
>>>> necessary and correct.
>>>>
>>>> git fetch git://github.com/legoscia/otp.git run_erl_exit_status
>>>> https://github.com/legoscia/otp/commit/29364cf9a6e1fcfd032503ff9888cffc4327b867 
>>>>
>>>>
>>>> Regards,
>>>> Magnus
>>>> _______________________________________________
>>>> erlang-patches mailing list
>>>> 
>>>> http://erlang.org/mailman/listinfo/erlang-patches
>>>>
>>
>
>



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