[erlang-questions] port_close/1 problem

Serge Aleynikov <>
Wed Oct 31 14:05:50 CET 2007

I reread this email and realized that I forgot to mention the fact that 
in my understanding port_close/1 merely closes its end of the pipe used 
to communicate with the port process.  So in this case if the running 
port program is in the middle of a blocking call it won't detect the 
closing of the file descriptor it uses to communicate with Erlang and 
will continue running.  So if I wanted to kill that port by sending an 
appropriate signal from Erlang how can I determine the OS pid of the port?

The obvious answer is to communicate that OS pid back to Erlang through 
the pipe, but in this particular case it takes over two to three minutes 
before the port loads all components and starts reading its end of the 
pipe, and I'd like to be able to kill it prior to that.

Any suggestions?


Serge Aleynikov wrote:
> Hi,
> I am having a problem shutting down a port program started using 
> open_port({spawn, Exe}, [binary, {packet, 2}, nouse_stdio, exit_status]).
> When the owner Pid dies or explicitly calls port_close(Port) the linked 
> OS process remains running.  It is a 3rd party binary interpreter.  Is 
> it because it might be intercepting SIGINT or some other signals?
> Is there a way to figure out it's OS pid and shut it down or is there a 
> "proper" way of killing it from within the emulator?  (doing 
> os:cmd("pkill ExeName") is not an option as there might be many 
> instances of ExeName running.  I looked through port_info/1 options but 
> don't see a way of determining port's OS pid.
> Serge
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