[pd] shell and ongoing processes

Yves Degoyon ydegoyon at free.fr
Sat May 25 18:27:01 CEST 2002

6 lines of codes were added to shell.c
to remove all these zombies.

about some definitions :

a zombie is a process that wants to terminate
but cannot warn its dead father,
so it is kept in system tables endlessly.

to clean up properly, the father's got to wait
the ending of its child before exiting.



Yves Degoyon wrote:

>>  yes, I am using netsend/receive, but the program on the other
>> end, piping the pdreceive into the program and forwarding the
>> output via pdsend back to PD, needs to be started. If this
>> were possible from shell, or otherwise from inside PD, then
>> I could have small units that started the piping chain within
>> the PD patch rather than having to start it myself from the command 
>> line.
> i've made a little test script ( here attached )
> that does the lauching of pdreceive
> and then communicates with pd.
> it DOES stay alive and the problem is rather
> that the process is not destroyed when i destroy
> the shell object, that's why <defunct> processes
> appear ( the father ( shell object ) is dead
> and the script is still alive ).
> then you cannot launch a new instance
> of your script if the former one holds
> an exclusive ressource ( like a port number ).
> in my example, this luckily works but
> this is surely unclean...
> cheers,
> yves

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