Enable IRQ Bit of Parallel Port is zero after unmasking Interrupt

[Alexander Sommerkorn]

Hello there,

I'm trying to use the parallel port interrupt to get a signal from
another pc. I pretty much stick to the following example but it won't
work in my case: http://psy.swan.ac.uk/staff/carter/qnx/tut_nto_parintr.htm

After receiving an interrupt an unmasking it, Bit 4 of the Control
Port happens to be 0 again inspite of the fact that I activated it at
paralell port initialization. Did anyone experience the same problem?

When I set the Bit high after unmasking another strange thing happens.
One interruptevent after another is triggered as long as the ACK-line
is low. When it turns high one more interrupt occurs and after that no
more interrupts occur.

I know perhaps this is not quite the perfect place to post my
question, if anyone knows a better forum please let me know.

best regards,
Alex