SYNOPSIS

       #include <ieee1284.h>


       int ieee1284_get_irq_fd (struct parport *port);

       int ieee1284_clear_irq (struct parport *port, unsigned int *count);

DESCRIPTION

       If  the port has a configured interrupt line and the port type supports
       interrupt notification, it is possible to obtain a file descriptor that
       may  be used for select(2) or poll(2). Any event (readable, writable or
       exception) means that an interrupt has been  triggered.  No  operations
       other than select or poll may be performed on the file descriptor.


       The port must be open in order to call ieee1284_get_irq_fd, and must be
       claimed when using select or poll.


       The caller must not close the file descriptor, and may not  use  it  at
       all when the port is not claimed.


       When   an   interrupt   has   been   detected,  the  caller  must  call
       ieee1284_clear_irq to clear the interrupt condition, at which point the
       number  of  interrupts  raised  can be obtained by supplying a non-NULL
       count.

RETURN VALUE

       For ieee1284_get_irq_fd: If the return value is negative then it is  an
       error code listed below. Otherwise it is a valid file descriptor.


       E1284_NOTAVAIL
              No such file descriptor is available.


       E1284_INVALIDPORT
              The port parameter is invalid (for instance, perhaps the port is
              not open).



       For ieee1284_clear_irq:


       E1284_OK
              The interrupt has been cleared. If count was not NULL the  count
              of interrupts has been atomically stored to count and reset.

AUTHOR

       Tim Waugh <twaugh@redhat.com>.



                                                        IEEE1284_GET_IRQ_FD(3)