lp(7)                          DG/UX 5.4R3.00                          lp(7)


NAME
       lp - DGC AViiON family line printer special files

DESCRIPTION
       The character special device lp provides access to either Centronics-
       compatible parallel or standard parallel device interface to line
       printer devices.  The driver supports all current Data General
       printer models.

       The printer driver takes the characters written to it and sends them
       to the line printer hardware. If the printer hardware takes special
       action in response to particular characters output to the device,
       such as form feeds, the application may take advantage of these
       features by outputting the appropriate characters, but there are no
       dependencies on these features within the driver. The driver does not
       perform any special paper spacing or other forms control to handle
       paper folds, etc.

       The open system call performs appropriate device dependent checks to
       determine that the printer device is online and ready to print;
       i.e., the printer must be ready to accept characters and print them
       without further operator intervention.  If the printer is not ready,
       the error ENXIO is returned.  A printer is an exclusive open device;
       the error ENXIO is returned if an attempt is made to open a printer
       that is already open.

       For the close system call, user visible functionality is the same as
       for an ordinary disk file.

       The read system call is not supported.  The error ENODEV is always
       returned.

       For the write system call, the contents of the caller's buffer are
       sent to the physical line printer.  If an error occurs on the I/O,
       the error EIO is returned.  If the printer is off-line when a write
       is started, or goes off-line while a write is in progress, the system
       call will pend until the printer is on-line and the data is written.

       The printer driver supports both the Centronics-compatible parallel
       and standard parallel interfaces.  The user configures the hardware
       through the System Control Monitor (SCM).  Refer to Using the AViiON
       (Trademark) System Control Monitor (SCM) for more information.

       Select always returns READY for both read and write operations.

FILES
       /dev/lp*

SEE ALSO
       lp(1).







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