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Groups > comp.lang.python > #91957

Re: fork/exec & close file descriptors

From Marko Rauhamaa <marko@pacujo.net>
Newsgroups comp.lang.python
Subject Re: fork/exec & close file descriptors
Date 2015-06-03 16:08 +0300
Organization A noiseless patient Spider
Message-ID <87wpzl3pnn.fsf@elektro.pacujo.net> (permalink)
References (7 earlier) <877frl6xxj.fsf@elektro.pacujo.net> <mkmhus$1sr$1@speranza.aioe.org> <556eee15$0$12975$c3e8da3$5496439d@news.astraweb.com> <878uc1567j.fsf@elektro.pacujo.net> <mailman.104.1433336055.13271.python-list@python.org>

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random832@fastmail.us:

> Why does the child process need to report the error at all? The parent
> process will find out naturally when *it* tries to close the same file
> descriptor.

That's not how it goes.

File descriptors are reference counted in the Linux kernel. Closes are
no-ops except for the last one that brings the reference count to zero.

If the parent should close the file before the child, no error is
returned to the parent.


Marko

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Re: fork/exec & close file descriptors Skip Montanaro <skip.montanaro@gmail.com> - 2015-06-02 08:58 -0500
  Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-02 18:28 +0300
    Re: fork/exec & close file descriptors Skip Montanaro <skip.montanaro@gmail.com> - 2015-06-02 10:42 -0500
      Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-02 19:24 +0300
        Re: fork/exec & close file descriptors Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2015-06-02 16:37 +0000
    Re: fork/exec & close file descriptors MrJean1 <MrJean1@gmail.com> - 2015-06-12 13:43 -0700
  Re: fork/exec & close file descriptors Alain Ketterlin <alain@universite-de-strasbourg.fr.invalid> - 2015-06-02 17:59 +0200
    Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-02 23:05 +0300
      Re: fork/exec & close file descriptors Alain Ketterlin <alain@universite-de-strasbourg.fr.invalid> - 2015-06-02 23:06 +0200
        Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-03 01:24 +0300
          Re: fork/exec & close file descriptors Alain Ketterlin <alain@universite-de-strasbourg.fr.invalid> - 2015-06-03 09:21 +0200
            Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-03 10:41 +0300
              Re: fork/exec & close file descriptors alister <alister.nospam.ware@ntlworld.com> - 2015-06-03 09:38 +0000
                Re: fork/exec & close file descriptors Steven D'Aprano <steve@pearwood.info> - 2015-06-03 22:07 +1000
                Re: fork/exec & close file descriptors alister <alister.nospam.ware@ntlworld.com> - 2015-06-03 12:18 +0000
                Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-03 15:27 +0300
                Re: fork/exec & close file descriptors alister <alister.nospam.ware@ntlworld.com> - 2015-06-03 13:05 +0000
                Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-03 17:49 +0300
                Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-03 15:25 +0300
                Re: fork/exec & close file descriptors random832@fastmail.us - 2015-06-03 08:54 -0400
                Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-03 16:08 +0300
                Re: fork/exec & close file descriptors random832@fastmail.us - 2015-06-03 09:21 -0400
                Re: fork/exec & close file descriptors Chris Angelico <rosuav@gmail.com> - 2015-06-03 23:32 +1000
                Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-03 16:33 +0300
                Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-03 17:43 +0300
                Re: fork/exec & close file descriptors random832@fastmail.us - 2015-06-03 16:08 -0400
                Re: fork/exec & close file descriptors Marko Rauhamaa <marko@pacujo.net> - 2015-06-04 00:09 +0300
                Re: fork/exec & close file descriptors random832@fastmail.us - 2015-06-03 16:07 -0400
                Re: fork/exec & close file descriptors Chris Angelico <rosuav@gmail.com> - 2015-06-04 07:54 +1000
        Re: fork/exec & close file descriptors Chris Angelico <rosuav@gmail.com> - 2015-06-03 09:54 +1000
          Re: fork/exec & close file descriptors Alain Ketterlin <alain@universite-de-strasbourg.fr.invalid> - 2015-06-03 09:11 +0200
            Re: fork/exec & close file descriptors random832@fastmail.us - 2015-06-03 08:21 -0400
              Re: fork/exec & close file descriptors Alain Ketterlin <alain@universite-de-strasbourg.fr.invalid> - 2015-06-03 15:16 +0200
        Re: fork/exec & close file descriptors Skip Montanaro <skip.montanaro@gmail.com> - 2015-06-02 20:21 -0500

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