Might I recommend adding a note to the documentation? It is not really intuitive that each child should need to close the end of the pipe it isn't using (especially since it is possible to create a child that has no explicit access to that end of the pipe, even though it has inherited the file descriptor).
2011/7/4 Charles-François Natali
<report@bugs.python.org>
Charles-François Natali <neologix@free.fr> added the comment:
That's because the other end of the pipe (p1) is open in the child process (FDs are inherited on fork()).
Just add
p1.close()
at the beginning of fn() and you'll get EOF.
Closing as invalid.
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nosy: +neologix
resolution: -> invalid
stage: -> committed/rejected
status: open -> closed