man4/lp.4

   1 '\" t
   2 .\" Copyright (c) Michael Haardt (michael@cantor.informatik.rwth-aachen.de), Sun Jan 15 19:16:33 1995
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  24 .\" Modified, Sun Feb 26 15:02:58 1995, faith@cs.unc.edu
  25 .TH LP 4 1995-01-15 "Linux" "Linux Programmer's Manual"
  26 .SH NAME
  27 lp \- line printer devices
  28 .SH SYNOPSIS
  29 .B #include <linux/lp.h>
  30 .SH CONFIGURATION
  31 \fBlp\fP[0\(en2] are character devices for the parallel line printers;
  32 they have major number 6 and minor number 0\(en2.
  33 The minor numbers
  34 correspond to the printer port base addresses 0x03bc, 0x0378 and 0x0278.
  35 Usually they have mode 220 and are owned by root and group lp.
  36 You can use printer ports either with polling or with interrupts.
  37 Interrupts are recommended when high traffic is expected, for example,
  38 for laser printers.
  39 For usual dot matrix printers polling will usually be enough.
  40 The default is polling.
  41 .SH DESCRIPTION
  42 The following
  43 .BR ioctl (2)
  44 calls are supported:
  45 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPTIME, int \fP\fIarg\fP\fB)\fP"
  46 Sets the amount of time that the driver sleeps before rechecking the printer
  47 when the printer's buffer appears to be filled to \fIarg\fP.
  48 If you have a fast printer, decrease this number;
  49 if you have a slow printer then increase it.
  50 This is in hundredths of a second, the default 2
  51 being 0.02 seconds.
  52 It only influences the polling driver.
  53 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPCHAR, int \fP\fIarg\fP\fB)\fP"
  54 Sets the maximum number of busy-wait iterations which the polling driver does
  55 while waiting for the printer to get ready for receiving a character to
  56 \fIarg\fP.
  57 If printing is too slow, increase this number; if the
  58 system gets too slow, decrease this number.
  59 The default is 1000.
  60 It only influences the polling driver.
  61 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPABORT, int \fP\fIarg\fP\fB)\fP"
  62 If \fIarg\fP is 0, the printer driver will retry on errors, otherwise
  63 it will abort.
  64 The default is 0.
  65 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPABORTOPEN, int \fP\fIarg\fP\fB)\fP"
  66 If \fIarg\fP is 0,
  67 .BR open (2)
  68 will be aborted on error, otherwise error will be ignored.
  69 The default is to ignore it.
  70 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPCAREFUL, int \fP\fIarg\fP\fB)\fP"
  71 If \fIarg\fP is 0, then the out-of-paper, offline and error signals are
  72 required to be false on all writes, otherwise they are ignored.
  73 The default is to ignore them.
  74 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPWAIT, int \fP\fIarg\fP\fB)\fP"
  75 Sets the number of busy waiting iterations to wait before strobing the
  76 printer to accept a just-written character, and the number of iterations to
  77 wait before turning the strobe off again,
  78 to \fIarg\fP.
  79 The specification says this time should be 0.5
  80 microseconds, but experience has shown the delay caused by the code is
  81 already enough.
  82 For that reason, the default value is 0.
  83 This is used for both the polling and the interrupt driver.
  84 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPSETIRQ, int \fP\fIarg\fP\fB)\fP"
  85 This
  86 .BR ioctl (2)
  87 requires superuser privileges.
  88 It takes an int containing the new IRQ as argument.
  89 As a side effect, the printer will be reset.
  90 When \fIarg\fP is 0, the polling driver will be used, which is also default.
  91 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPGETIRQ, int *\fP\fIarg\fP\fB)\fP"
  92 Stores the currently used IRQ in \fIarg\fP.
  93 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPGETSTATUS, int *\fP\fIarg\fP\fB)\fP"
  94 Stores the value of the status port in \fIarg\fP.
  95 The bits have the following meaning:
  96 .TS
  97 l l.
  98 LP_PBUSY        inverted busy input, active high
  99 LP_PACK unchanged acknowledge input, active low
 100 LP_POUTPA       unchanged out-of-paper input, active high
 101 LP_PSELECD      unchanged selected input, active high
 102 LP_PERRORP      unchanged error input, active low
 103 .TE
 104 .sp
 105 Refer to your printer manual for the meaning of the signals.
 106 Note that undocumented bits may also be set, depending on your printer.
 107 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPRESET)\fP"
 108 Resets the printer.
 109 No argument is used.
 110 .SH FILES
 111 /dev/lp*
 112 .\" .SH AUTHORS
 113 .\" The printer driver was originally written by Jim Weigand and Linus
 114 .\" Torvalds.
 115 .\" It was further improved by Michael K.\& Johnson.
 116 .\" The interrupt code was written by Nigel Gamble.
 117 .\" Alan Cox modularized it.
 118 .\" LPCAREFUL, LPABORT, LPGETSTATUS were added by Chris Metcalf.
 119 .SH "SEE ALSO"
 120 .BR chmod (1),
 121 .BR chown (1),
 122 .BR mknod (1),
 123 .BR lpcntl (8),
 124 .BR tunelp (8)