Section (4) lp
Name
lp — line printer devices
Synopsis
#include <linux/lp.h>
CONFIGURATION
lp
[0–2] are character
devices for the parallel line printers; they have major
number 6 and minor number 0–2. The minor numbers
correspond to the printer port base addresses 0x03bc, 0x0378
and 0x0278. Usually they have mode 220 and are owned by root
and group lp. You can use printer ports either with polling
or with interrupts. Interrupts are recommended when high
traffic is expected, for example, for laser printers. For
typical dot matrix printers, polling will usually be enough.
The default is polling.
DESCRIPTION
The following ioctl(2) calls are supported:
- int
ioctl(int
fd
, LPTIME, intarg
) -
Sets the amount of time that the driver sleeps before rechecking the printer when the printer_zsingle_quotesz_s buffer appears to be filled to
arg
. If you have a fast printer, decrease this number; if you have a slow printer, then increase it. This is in hundredths of a second, the default 2 being 0.02 seconds. It influences only the polling driver. - int
ioctl(int
fd
, LPCHAR, intarg
) -
Sets the maximum number of busy-wait iterations which the polling driver does while waiting for the printer to get ready for receiving a character to
arg
. If printing is too slow, increase this number; if the system gets too slow, decrease this number. The default is 1000. It influences only the polling driver. - int
ioctl(int
fd
, LPABORT, intarg
) -
If
arg
is 0, the printer driver will retry on errors, otherwise it will abort. The default is 0. - int
ioctl(int
fd
, LPABORTOPEN, intarg
) -
If
arg
is 0, open(2) will be aborted on error, otherwise error will be ignored. The default is to ignore it. - int
ioctl(int
fd
, LPCAREFUL, intarg
) -
If
arg
is 0, then the out-of-paper, offline, and error signals are required to be false on all writes, otherwise they are ignored. The default is to ignore them. - int
ioctl(int
fd
, LPWAIT, intarg
) -
Sets the number of busy waiting iterations to wait before strobing the printer to accept a just-written character, and the number of iterations to wait before turning the strobe off again, to
arg
. The specification says this time should be 0.5 microseconds, but experience has shown the delay caused by the code is already enough. For that reason, the default value is 0. This is used for both the polling and the interrupt driver. - int
ioctl(int
fd
, LPSETIRQ, intarg
) -
This ioctl(2) requires superuser privileges. It takes an int containing the new IRQ as argument. As a side effect, the printer will be reset. When
arg
is 0, the polling driver will be used, which is also default. - int
ioctl(int
fd
, LPGETIRQ, int *arg
) -
Stores the currently used IRQ in
arg
. - int
ioctl(int
fd
, LPGETSTATUS, int *arg
) -
Stores the value of the status port in
arg
. The bits have the following meaning:
LP_PBUSY | inverted busy input, active high |
LP_PACK | unchanged acknowledge input, active low |
LP_POUTPA | unchanged out-of-paper input, active high |
LP_PSELECD | unchanged selected input, active high |
LP_PERRORP | unchanged error input, active low |
-
Refer to your printer manual for the meaning of the signals. Note that undocumented bits may also be set, depending on your printer.
- int ioctl(int
fd
, LPRESET) -
Resets the printer. No argument is used.
- int ioctl(int
COLOPHON
This page is part of release 5.04 of the Linux man-pages
project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
t Copyright (c) Michael Haardt (michaelcantor.informatik.rwth-aachen.de), Sun Jan 15 19:16:33 1995 %%%LICENSE_START(GPLv2+_DOC_FULL) This is free documentation; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU General Public License_zsingle_quotesz_s references to object code and executables are to be interpreted as the output of any document formatting or typesetting system, including intermediate and printed output. This manual is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this manual; if not, see <http://www.gnu.org/licenses/>. %%%LICENSE_END Modified, Sun Feb 26 15:02:58 1995, faithcs.unc.edu |