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Re: Pass data to a subprocess

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Date Wed, 01 Aug 2012 16:42:44 +0200
From Laszlo Nagy <gandalf@shopzeus.com>
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Subject Re: Pass data to a subprocess
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>>> Yes, I think that is correct.
>> I don't understand why detaching a child process on Linux/Unix would
>> make IPC stop working.  Can somebody explain?
>>
> It is implemented with shared memory. I think (although I'm not 100% 
> sure) that shared memory is created *and freed up* (shm_unlink() 
> system call) by the parent process. It makes sense, because the child 
> processes will surely die with the parent. If you detach a child 
> process, then it won't be killed with its original parent. But the 
> shared memory will be freed by the original parent process anyway. I 
> suspect that the child that has mapped that shared memory segment will 
> try to access a freed up resource, do a segfault or something similar.
So detaching the child process will not make IPC stop working. But 
exiting from the original parent process will. (And why else would you 
detach the child?)

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Thread

Re: Pass data to a subprocess Laszlo Nagy <gandalf@shopzeus.com> - 2012-08-01 10:19 +0200
  Re: Pass data to a subprocess Roy Smith <roy@panix.com> - 2012-08-01 06:59 -0400
    Re: Pass data to a subprocess Laszlo Nagy <gandalf@shopzeus.com> - 2012-08-01 13:07 +0200
    Re: Pass data to a subprocess Laszlo Nagy <gandalf@shopzeus.com> - 2012-08-01 13:26 +0200
    Re: Pass data to a subprocess andrea crotti <andrea.crotti.0@gmail.com> - 2012-08-01 14:25 +0100
    Re: Pass data to a subprocess Roy Smith <roy@panix.com> - 2012-08-01 15:07 -0400
  Re: Pass data to a subprocess Grant Edwards <invalid@invalid.invalid> - 2012-08-01 14:16 +0000
    Re: Pass data to a subprocess Laszlo Nagy <gandalf@shopzeus.com> - 2012-08-01 16:32 +0200
      Re: Pass data to a subprocess Grant Edwards <invalid@invalid.invalid> - 2012-08-01 19:48 +0000
        Re: Pass data to a subprocess Laszlo Nagy <gandalf@shopzeus.com> - 2012-08-02 08:10 +0200
          Re: Pass data to a subprocess Grant Edwards <invalid@invalid.invalid> - 2012-08-02 14:29 +0000
        Re: Pass data to a subprocess Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-02 13:21 -0400
    Re: Pass data to a subprocess Laszlo Nagy <gandalf@shopzeus.com> - 2012-08-01 16:42 +0200
    Re: Pass data to a subprocess andrea crotti <andrea.crotti.0@gmail.com> - 2012-08-01 16:24 +0100

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