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To: linux-kernel@vger.kernel.org
From: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: Really odd behavior of overlapping named pipes?
Date: 26 Jan 2002 01:07:06 -0800
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Copyright: Copyright 2002 H. Peter Anvin - All Rights Reserved
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Followup to:  <20020126021610.YKAU20810.femail29.sdc1.sfba.home.com@there>
By author:    Rob Landley <landley@trommello.org>
In newsgroup: linux.dev.kernel
>
> You apparently can't share named pipe instances.  They short-circuit.  When I 
> open four command shells, do a mkfifo /tmp/fifo, and then do the following:
> 
> Shell one and two:
> 
> cat /tmp/mkfifo
> 
> Shell three and four:
> 
> cat > /tmp/mkfifo
> 
> Both of the write windows go into the FIRST read window.  The second read 
> window continues to block on the open, getting nothing.
> 

A pipe is *one* communications channel.

A socket is *a communications channel creator*.

It sounds like what you're expecting is what would happen if we
allowed open() on a Unix domain socket to do the obvious thing (can
we, pretty please?)

	-hpa
-- 
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."
http://www.zytor.com/~hpa/puzzle.txt	<amsp@zytor.com>
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