This library is intended to be used by applications that need to
communicate with (or at least identify) devices that are attached via a
parallel port.

For Linux, there are some wrinkles in communicating with devices on
parallel ports (see /usr/share/doc/packages/libieee1284/README). The
aim of this library is to take all the worry about these wrinkles from
the application. It figures out which method is appropriate for the
currently running kernel. For instance, if the application wants to
know the device ID of a device on a particular port, it asks the
library for the the device ID. The library then figures out if it is
available via /proc (in any of the possible locations) and, if not,
tries asking the device itself. If /dev/parport0 is not available for
use, it tries ioperm; if that fails, it tries /dev/port. The
application does not have to care.