man/backend.man - platform/external/libcups - Git at Google

 .\"
 .\" "$Id: backend.man 6649 2007-07-11 21:46:42Z mike $"
 .\"
 .\"   Backend man page for the Common UNIX Printing System (CUPS).
 .\"
 .\"   Copyright 2007 by Apple Inc.
 .\"   Copyright 1997-2006 by Easy Software Products.
 .\"
 .\"   These coded instructions, statements, and computer programs are the
 .\"   property of Apple Inc. and are protected by Federal copyright
 .\"   law.  Distribution and use rights are outlined in the file "LICENSE.txt"
 .\"   which should have been included with this file.  If this file is
 .\"   file is missing or damaged, see the license at "http://www.cups.org/".
 .\"
 .TH backend 7 "Common UNIX Printing System" "20 March 2006" "Apple Inc."

 .SH NAME
 backend \- cups backend transmission interfaces

 .SH SYNOPSIS
 .B backend
 .br
 .B backend
 job user title num-copies options [
 .I filename
 ]

 .SH DESCRIPTION
 Backends are a special type of \fIfilter(7)\fR which is used to
 send print data to and discover different devices on the system.

 .LP
 Like filters, backends must be capable of reading from a filename
 on the command-line or from the standard input, copying the
 standard input to a temporary file as required by the physical
 interface.

 .LP
 The command name (argv[0]) is set to the device URI of the
 destination printer. Starting with CUPS 1.1.22, any
 authentication information in argv[0] is removed, so
 backend developers are urged to use the DEVICE_URI environment
 variable whenever authentication information is required. The
 CUPS API includes a \fIcupsBackendDeviceURI\fR function for
 retrieving the correct device URI.

 .LP
 Back-channel data from the device should be relayed to the job
 filters by writing to file descriptor 3. The CUPS API includes
 the \fIcupsBackChannelWrite\fR function for this purpose.

 .SH DEVICE DISCOVERY
 When run with no arguments, the backend should list the devices
 and schemes it supports or is advertising to stdout. The output
 consists of zero or more lines consisting of any of the following
 forms:

 .nf
     device-class scheme "Unknown" "device-info"
     device-class device-uri "device-make-and-model" "device-info"
     device-class device-uri "device-make-and-model" "device-info" "device-id"
 .fi

 .LP
 The \fIdevice-class\fR field is one of the following values:

 .TP 5
 direct
 .br
 The device-uri refers to a specific direct-access device with no
 options, such as a parallel, USB, or SCSI device.

 .TP 5
 file
 .br
 The device-uri refers to a file on disk.

 .TP 5
 network
 .br
 The device-uri refers to a networked device and conforms to the
 general form for network URIs.

 .TP 5
 serial
 .br
 The device-uri refers to a serial device with configurable baud
 rate and other options. If the device-uri contains a baud value,
 it represents the maximum baud rate supported by the device.

 .LP
 The \fIscheme\fR field provides the URI scheme that is supported
 by the backend. Backends should use this form only when the
 backend supports any URI using that scheme. The \fIdevice-uri\fR
 field specifies the full URI to use when communicating with the
 device.

 .LP
 The \fIdevice-make-and-model\fR field specifies the make and
 model of the device, e.g. "Acme Foojet 2000". If the make and
 model is not known, you must report "Unknown".

 .LP
 The \fIdevice-info\fR field specifies additional information
 about the device. Typically this includes the make and model
 along with the port number or network address, e.g. "Acme Foojet
 2000 USB #1".

 .LP
 The optional \fIdevice-id\fR field specifies the IEEE-1284 device
 ID string for the device, which is used to select a matching
 driver.

 .SH PERMISSIONS
 Backends without world execute permissions are run as the root
 user. Otherwise, the backend is run using the unprivileged user
 account, typically "lp".

 .SH EXIT CODES
 The following exit codes are defined for backends; C API
 constants defined in the <cups/backend.h> header file are defined
 in parenthesis:

 .TP 5
 0 (CUPS_BACKEND_OK)
 .br
 The print file was successfully transmitted to the device or
 remote server.

 .TP 5
 1 (CUPS_BACKEND_FAILED)
 .br
 The print file was not successfully transmitted to the device or
 remote server. The scheduler will respond to this by canceling
 the job, retrying the job, or stopping the queue depending on the
 state of the error-policy attribute.

 .TP 5
 2 (CUPS_BACKEND_AUTH_REQUIRED)
 .br
 The print file was not successfully transmitted because valid
 authentication information is required. The scheduler will
 respond to this by holding the job and adding the
 authentication-required job-reasons keyword.

 .TP 5
 3 (CUPS_BACKEND_HOLD)
 .br
 The print file was not successfully transmitted because it cannot
 be printed at this time. The scheduler will respond to this by
 holding the job.

 .TP 5
 4 (CUPS_BACKEND_STOP)
 .br
 The print file was not successfully transmitted because it cannot
 be printed at this time. The scheduler will respond to this by
 stopping the queue.

 .TP 5
 5 (CUPS_BACKEND_CANCEL)
 .br
 The print file was not successfully transmitted because one or
 more attributes are not supported. The scheduler will respond to
 this by canceling the job.

 .PP
 All other exit code values are reserved.

 .SH SEE ALSO
 \fIcupsd(8)\fR, \fIcupsd.conf(5)\fR, \fIfilter(7)\fR
 .br
 http://localhost:631/help

 .SH COPYRIGHT
 Copyright 2007 by Apple Inc.
 .\"
 .\" End of "$Id: backend.man 6649 2007-07-11 21:46:42Z mike $".
 .\"
	.\"
	.\" "$Id: backend.man 6649 2007-07-11 21:46:42Z mike $"
	.\"
	.\" Backend man page for the Common UNIX Printing System (CUPS).
	.\"
	.\" Copyright 2007 by Apple Inc.
	.\" Copyright 1997-2006 by Easy Software Products.
	.\"
	.\" These coded instructions, statements, and computer programs are the
	.\" property of Apple Inc. and are protected by Federal copyright
	.\" law. Distribution and use rights are outlined in the file "LICENSE.txt"
	.\" which should have been included with this file. If this file is
	.\" file is missing or damaged, see the license at "http://www.cups.org/".
	.\"
	.TH backend 7 "Common UNIX Printing System" "20 March 2006" "Apple Inc."

	.SH NAME
	backend \- cups backend transmission interfaces

	.SH SYNOPSIS
	.B backend
	.br
	.B backend
	job user title num-copies options [
	.I filename
	]

	.SH DESCRIPTION
	Backends are a special type of \fIfilter(7)\fR which is used to
	send print data to and discover different devices on the system.

	.LP
	Like filters, backends must be capable of reading from a filename
	on the command-line or from the standard input, copying the
	standard input to a temporary file as required by the physical
	interface.

	.LP
	The command name (argv[0]) is set to the device URI of the
	destination printer. Starting with CUPS 1.1.22, any
	authentication information in argv[0] is removed, so
	backend developers are urged to use the DEVICE_URI environment
	variable whenever authentication information is required. The
	CUPS API includes a \fIcupsBackendDeviceURI\fR function for
	retrieving the correct device URI.

	.LP
	Back-channel data from the device should be relayed to the job
	filters by writing to file descriptor 3. The CUPS API includes
	the \fIcupsBackChannelWrite\fR function for this purpose.

	.SH DEVICE DISCOVERY
	When run with no arguments, the backend should list the devices
	and schemes it supports or is advertising to stdout. The output
	consists of zero or more lines consisting of any of the following
	forms:

	.nf
	device-class scheme "Unknown" "device-info"
	device-class device-uri "device-make-and-model" "device-info"
	device-class device-uri "device-make-and-model" "device-info" "device-id"
	.fi

	.LP
	The \fIdevice-class\fR field is one of the following values:

	.TP 5
	direct
	.br
	The device-uri refers to a specific direct-access device with no
	options, such as a parallel, USB, or SCSI device.

	.TP 5
	file
	.br
	The device-uri refers to a file on disk.

	.TP 5
	network
	.br
	The device-uri refers to a networked device and conforms to the
	general form for network URIs.

	.TP 5
	serial
	.br
	The device-uri refers to a serial device with configurable baud
	rate and other options. If the device-uri contains a baud value,
	it represents the maximum baud rate supported by the device.

	.LP
	The \fIscheme\fR field provides the URI scheme that is supported
	by the backend. Backends should use this form only when the
	backend supports any URI using that scheme. The \fIdevice-uri\fR
	field specifies the full URI to use when communicating with the
	device.

	.LP
	The \fIdevice-make-and-model\fR field specifies the make and
	model of the device, e.g. "Acme Foojet 2000". If the make and
	model is not known, you must report "Unknown".

	.LP
	The \fIdevice-info\fR field specifies additional information
	about the device. Typically this includes the make and model
	along with the port number or network address, e.g. "Acme Foojet
	2000 USB #1".

	.LP
	The optional \fIdevice-id\fR field specifies the IEEE-1284 device
	ID string for the device, which is used to select a matching
	driver.

	.SH PERMISSIONS
	Backends without world execute permissions are run as the root
	user. Otherwise, the backend is run using the unprivileged user
	account, typically "lp".

	.SH EXIT CODES
	The following exit codes are defined for backends; C API
	constants defined in the <cups/backend.h> header file are defined
	in parenthesis:

	.TP 5
	0 (CUPS_BACKEND_OK)
	.br
	The print file was successfully transmitted to the device or
	remote server.

	.TP 5
	1 (CUPS_BACKEND_FAILED)
	.br
	The print file was not successfully transmitted to the device or
	remote server. The scheduler will respond to this by canceling
	the job, retrying the job, or stopping the queue depending on the
	state of the error-policy attribute.

	.TP 5
	2 (CUPS_BACKEND_AUTH_REQUIRED)
	.br
	The print file was not successfully transmitted because valid
	authentication information is required. The scheduler will
	respond to this by holding the job and adding the
	authentication-required job-reasons keyword.

	.TP 5
	3 (CUPS_BACKEND_HOLD)
	.br
	The print file was not successfully transmitted because it cannot
	be printed at this time. The scheduler will respond to this by
	holding the job.

	.TP 5
	4 (CUPS_BACKEND_STOP)
	.br
	The print file was not successfully transmitted because it cannot
	be printed at this time. The scheduler will respond to this by
	stopping the queue.

	.TP 5
	5 (CUPS_BACKEND_CANCEL)
	.br
	The print file was not successfully transmitted because one or
	more attributes are not supported. The scheduler will respond to
	this by canceling the job.

	.PP
	All other exit code values are reserved.

	.SH SEE ALSO
	\fIcupsd(8)\fR, \fIcupsd.conf(5)\fR, \fIfilter(7)\fR
	.br
	http://localhost:631/help

	.SH COPYRIGHT
	Copyright 2007 by Apple Inc.
	.\"
	.\" End of "$Id: backend.man 6649 2007-07-11 21:46:42Z mike $".
	.\"