[Linux-parport] libieee1284 open/claim gives ppdev error

christian.braun at ch.abb.com christian.braun at ch.abb.com
Wed Mar 17 16:52:08 GMT 2004

I've now reimplemented my program doing without the libieee1284 directly 
using ppdev instead. It now works, however only when I don't try to claim 
the port for exclusive usage. If I use

ioctl(portFileDescriptor, PPEXCL);

it will fail claiming the port afterwards with

ioctl(portFileDescriptor, PPCLAIM);

resulting in the same error message

"ppdev0: failed to register device!"

as I experienced earlier when I was using the libieee1284.
There is however no other program running at that time which I know of 
that uses the parallel port and could therefore block it.

What could that problem come from and how could I avoid it?

Thanks for your help!

Message from Tim Waugh <twaugh at redhat.com> received on 09.03.2004 17:07

09.03.2004 17:07

Tim Waugh <twaugh at redhat.com>

        To:     christian.braun at ch.abb.com
        cc:     Linux-parport at lists.infradead.org
        Subject:        Re: [Linux-parport] libieee1284 open/claim gives ppdev error

You can set the environment variable LIBIEEE1284_DEBUG (to anything)
to find out more about what the library is up to.


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