Re: select() on FIFOs

Anthony Barbachan (barbacha@Hinako.AMBusiness.com)
Thu, 24 Dec 1998 20:43:21 -0500

Open the fifo in Read/Write mode (O_RDWR). This will work around the
problem as a reader will always exist for your fifo. The problem is that
once the first reader closes the fifo your read handle of the fifo is set to
readonly.

-----Original Message-----
From: Martynas Kunigelis <mkunigelis@alna.lt>
To: linux-kernel@vger.rutgers.edu <linux-kernel@vger.rutgers.edu>
Date: Thursday, December 24, 1998 9:43 AM
Subject: select() on FIFOs

>Hello,
>
>I am trying to write a pseudo client/server program, where clients talk
>to the server through a named pipe. In the server, I intended to have
>the FIFO open in O_NONBLOCK mode, and then use select() to check when
>there's data to read. However, when a client opens the communication
>FIFO, writes some data to it and then closes it, all subsequent select()
>calls in the server return, saying that there is data to read in the
>FIFO. However, there's no data to read, and the server gets stuck in a
>loop:
>
> select() returns 1
> read() returns 0
>
>What is the correct solution? I can get it to work having the server
>open() and close() the FIFO in blocking mode for each session, but this
>does not appeal to me. I wish a had the Stevens book... :) (Ah, and
>input multiplexing is not a problem as the clients will never write to
>the FIFO concurrently).
>
>Please CC: me on all replies, as I'm not subscribed to the list.
>Thanks in advance and merry Christmas to everyone!
>
>-Martynas
>
>-
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