Re: [PARPORT] ppdev question

From: Fred Barnes (
Date: Thu Mar 01 2001 - 10:49:30 EST

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    > I am trying to use ppdev to ensure that my printer and my scanner share
    > correctly the parallel port. From the tests I done, it seems that ppdev lets you
    > claim the port even if it is used by lp.
    > For instance, the following program may be ran successfully when a printing
    > is in progress, while I expected it to fail with 'tp: cannot claim port':
    > <snip code>

    If I remember correctly, multiple things can use the parallel port
    concurrently, via the use of Tim's parport sharing stuff. To a certain
    extent, this should happen transparently. If you want absolute control
    of the parport, you have to issue the EXCL (exclusive) ioctl.

    Hope that helps,


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