[PARPORT] Timeout on write

From: Brad Pepers (brad@linuxcanada.com)
Date: Wed Oct 10 2001 - 13:05:25 EDT

  • Next message: Tim Waugh: "Re: [PARPORT] Timeout on write"

    With the latest Linux kernels (using 2.4.10 right now), I can't seem to find
    a way to make a write fail if there is no parallel port device. For example
    I have a Epson TM-T88 printer on the parallel port and I send a status
    request to it every few seconds. If the printer gets turned off I want the
    write to just fail immediately. In the past I could use "tunelp -a on" to
    get this behaviour but it doesn't seem to work anymore.

    Anything I can do to help get this working again? Am I doing something
    wrong? This is really required to use point-of-sale printers on Linux since
    the software can't just halt when a user turns a printer off so I would
    really like to get it fixed!

    PS: once I get past this problem with writes, I will need to see if I can
    also make sure reads work properly. What I need is non-blocking behaviour.
    I will request a read for a few bytes but if there aren't enough available
    (or none), I want it to just return back that it read 0 is how ever many
    bytes were available. Does the printer driver handle the non-blocked flag

    Brad Pepers

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