From mboxrd@z Thu Jan  1 00:00:00 1970
Message-Id: <200608312045.k7VKjsw01324@demeter.cs.utwente.nl>
To: Fans of the OS Plan 9 from Bell Labs <9fans@cse.psu.edu>
Subject: Re: [9fans] trying to understand how fork/pipe a filtering program
In-reply-to: Your message of "Thu, 31 Aug 2006 21:24:58 +0100."
	<43797a19394ce8f10a30710c76d1d46b@vitanuova.com> 
References: <43797a19394ce8f10a30710c76d1d46b@vitanuova.com> 
From: Axel Belinfante <Axel.Belinfante@cs.utwente.nl>
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Content-ID: <1318.1157057153.1@demeter.cs.utwente.nl.cs.utwente.nl>
Date: Thu, 31 Aug 2006 22:45:54 +0200
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> oops skim reading again!
> i'd thought i'd read "using two pipes unidirectionally *doesn't* make it work."
> so why can't you just use two pipes unidirectionally? you can't do anything
> else in this example, because by using the same pipe for input and output,
> the command itself keeps its own input open, and therefore never receives EOF.

seems it took me a while to realize that.


the funny thing is that, somehow, using the same pipe
for input and output does work (at least for me)
if in the parent I have an fprint or a sleep between
the writing+closing part and the reading part,
as in the message with which I started this thread.
that said, I'm much happier with the 'two unidirectional pipes' solution.

Axel.