[vox-tech] Receiving an interrupt from a parallel port using xlib

[Bill Kendrick]

On Tue, Mar 16, 2004 at 02:58:29PM +1100, Julie Russell wrote:
> Hi everyone,
> 
> I have written an application in xlib that currently takes an xevent and
> processes it from the keyboard. Due to changes in hardware constraints I now
> have to take that event from a parallel port by receiving an interrupt. Does
> anyone know how if you can receive this signal using x libraries, or the
> best way to talk to the port via x?

This is beyond the scope of Xlib itself.  X doesn't go much further than
your mouse/keyboard/videocard.  :^)

Of course, that's not stopping you from using some /other/ libraries to
talk to the parallel port within the same (Xlib-based) application. :^)


Unfortunately, I've never done parallel port code, so I wouldn't know where
to begin, except I guess you want to talk to "/dev/lp0" or "/dev/lp1".


> I would like to implement this without
> making too many changes to the event handler and the architecture of the
> application.

Been a while since I did straight Xlib, but I suppose it could be possible
to have your own 'user-specified' events come in (and get handled by your
main event loop, just like the keyboard events that X gives you directly),
and have some code that 'pushes' events into the queue when parallel port
action happens.

I'm sure someone else here can explain all this better than I. ;^)

Good luck!

-bill!
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