man4/lp.4

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   2 .\" Copyright (c) Michael Haardt (michael@cantor.informatik.rwth-aachen.de),
   3 .\"     Sun Jan 15 19:16:33 1995
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  26 .\" Modified, Sun Feb 26 15:02:58 1995, faith@cs.unc.edu
  27 .TH LP 4 1995-01-15 "Linux" "Linux Programmer's Manual"
  28 .SH NAME
  29 lp \- line printer devices
  30 .SH SYNOPSIS
  31 .B #include <linux/lp.h>
  32 .SH CONFIGURATION
  33 \fBlp\fP[0\(en2] are character devices for the parallel line printers;
  34 they have major number 6 and minor number 0\(en2.
  35 The minor numbers
  36 correspond to the printer port base addresses 0x03bc, 0x0378 and 0x0278.
  37 Usually they have mode 220 and are owned by root and group lp.
  38 You can use printer ports either with polling or with interrupts.
  39 Interrupts are recommended when high traffic is expected, for example,
  40 for laser printers.
  41 For typical dot matrix printers, polling will usually be enough.
  42 The default is polling.
  43 .SH DESCRIPTION
  44 The following
  45 .BR ioctl (2)
  46 calls are supported:
  47 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPTIME, int \fP\fIarg\fP\fB)\fP"
  48 Sets the amount of time that the driver sleeps before rechecking the printer
  49 when the printer's buffer appears to be filled to
  50 .IR arg .
  51 If you have a fast printer, decrease this number;
  52 if you have a slow printer, then increase it.
  53 This is in hundredths of a second, the default 2
  54 being 0.02 seconds.
  55 It influences only the polling driver.
  56 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPCHAR, int \fP\fIarg\fP\fB)\fP"
  57 Sets the maximum number of busy-wait iterations which the polling driver does
  58 while waiting for the printer to get ready for receiving a character to
  59 .IR arg .
  60 If printing is too slow, increase this number; if the
  61 system gets too slow, decrease this number.
  62 The default is 1000.
  63 It influences only the polling driver.
  64 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPABORT, int \fP\fIarg\fP\fB)\fP"
  65 If
  66 .I arg
  67 is 0, the printer driver will retry on errors, otherwise
  68 it will abort.
  69 The default is 0.
  70 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPABORTOPEN, int \fP\fIarg\fP\fB)\fP"
  71 If
  72 .I arg
  73 is 0,
  74 .BR open (2)
  75 will be aborted on error, otherwise error will be ignored.
  76 The default is to ignore it.
  77 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPCAREFUL, int \fP\fIarg\fP\fB)\fP"
  78 If
  79 .I arg
  80 is 0, then the out-of-paper, offline and error signals are
  81 required to be false on all writes, otherwise they are ignored.
  82 The default is to ignore them.
  83 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPWAIT, int \fP\fIarg\fP\fB)\fP"
  84 Sets the number of busy waiting iterations to wait before strobing the
  85 printer to accept a just-written character, and the number of iterations to
  86 wait before turning the strobe off again,
  87 to
  88 .IR arg .
  89 The specification says this time should be 0.5
  90 microseconds, but experience has shown the delay caused by the code is
  91 already enough.
  92 For that reason, the default value is 0.
  93 This is used for both the polling and the interrupt driver.
  94 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPSETIRQ, int \fP\fIarg\fP\fB)\fP"
  95 This
  96 .BR ioctl (2)
  97 requires superuser privileges.
  98 It takes an
  99 .I int
 100 containing the new IRQ as argument.
 101 As a side effect, the printer will be reset.
 102 When
 103 .I arg
 104 is 0, the polling driver will be used, which is also default.
 105 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPGETIRQ, int *\fP\fIarg\fP\fB)\fP"
 106 Stores the currently used IRQ in
 107 .IR arg .
 108 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPGETSTATUS, int *\fP\fIarg\fP\fB)\fP"
 109 Stores the value of the status port in
 110 .IR arg .
 111 The bits have the following meaning:
 112 .TS
 113 l l.
 114 LP_PBUSY        inverted busy input, active high
 115 LP_PACK unchanged acknowledge input, active low
 116 LP_POUTPA       unchanged out-of-paper input, active high
 117 LP_PSELECD      unchanged selected input, active high
 118 LP_PERRORP      unchanged error input, active low
 119 .TE
 120 .sp
 121 Refer to your printer manual for the meaning of the signals.
 122 Note that undocumented bits may also be set, depending on your printer.
 123 .IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPRESET)\fP"
 124 Resets the printer.
 125 No argument is used.
 126 .SH FILES
 127 /dev/lp*
 128 .\" .SH AUTHORS
 129 .\" The printer driver was originally written by Jim Weigand and Linus
 130 .\" Torvalds.
 131 .\" It was further improved by Michael K.\& Johnson.
 132 .\" The interrupt code was written by Nigel Gamble.
 133 .\" Alan Cox modularized it.
 134 .\" LPCAREFUL, LPABORT, LPGETSTATUS were added by Chris Metcalf.
 135 .SH SEE ALSO
 136 .BR chmod (1),
 137 .BR chown (1),
 138 .BR mknod (1),
 139 .BR lpcntl (8),
 140 .BR tunelp (8)