</head>
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<!--
- "$Id: api-filter.shtml 5138 2006-02-21 10:49:06Z mike $"
+ "$Id: api-filter.shtml 6649 2007-07-11 21:46:42Z mike $"
Filter and backend API introduction for the Common UNIX Printing System (CUPS).
- Copyright 1997-2006 by Easy Software Products.
+ Copyright 2007 by Apple Inc.
+ Copyright 1997-2006 by Easy Software Products, all rights reserved.
These coded instructions, statements, and computer programs are the
- property of Easy Software Products 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 missing or damaged please contact Easy Software Products
- at:
-
- Attn: CUPS Licensing Information
- Easy Software Products
- 44141 Airport View Drive, Suite 204
- Hollywood, Maryland 20636 USA
-
- Voice: (301) 373-9600
- EMail: cups-info@cups.org
- WWW: http://www.cups.org
+ 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/".
-->
<h2 class='title'>Introduction</h2>
<h3 class='title'><span class='info'> CUPS 1.2 </span><a name='cupsBackChannelRead'>cupsBackChannelRead()</a></h3>
<h4>Description</h4>
<p>Read data from the backchannel.
-
-Reads up to "bytes" bytes from the backchannel. The "timeout"
+<p>Reads up to "bytes" bytes from the backchannel. The "timeout"
parameter controls how many seconds to wait for the data - use
0.0 to return immediately if there is no data, -1.0 to wait
for data indefinitely.
-</p>
+
<h4>Syntax</h4>
-<pre>
-ssize_t
+<p><tt>
+ssize_t<br>
cupsBackChannelRead(
char * buffer,
size_t bytes,
double timeout);
-</pre>
+</tt></p>
<h4>Arguments</h4>
-<div class='table'><table align='center' border='1' width='80%' cellpadding='5' cellspacing='0'>
+<div class='table'><table align='center' border='1' width='80%' cellpadding='5' cellspacing='0' summary='Arguments'>
<thead><tr><th>Name</th><th>Description</th></tr></thead>
<tbody>
<tr><td><tt>buffer</tt></td><td>Buffer to read</td></tr>
<h3 class='title'><span class='info'> CUPS 1.2 </span><a name='cupsBackChannelWrite'>cupsBackChannelWrite()</a></h3>
<h4>Description</h4>
<p>Write data to the backchannel.
-
-Writes "bytes" bytes to the backchannel. The "timeout" parameter
+<p>Writes "bytes" bytes to the backchannel. The "timeout" parameter
controls how many seconds to wait for the data to be written - use
0.0 to return immediately if the data cannot be written, -1.0 to wait
indefinitely.
-</p>
+
<h4>Syntax</h4>
-<pre>
-ssize_t
+<p><tt>
+ssize_t<br>
cupsBackChannelWrite(
const char * buffer,
size_t bytes,
double timeout);
-</pre>
+</tt></p>
<h4>Arguments</h4>
-<div class='table'><table align='center' border='1' width='80%' cellpadding='5' cellspacing='0'>
+<div class='table'><table align='center' border='1' width='80%' cellpadding='5' cellspacing='0' summary='Arguments'>
<thead><tr><th>Name</th><th>Description</th></tr></thead>
<tbody>
<tr><td><tt>buffer</tt></td><td>Buffer to write</td></tr>
<h3 class='title'><span class='info'> CUPS 1.3 </span><a name='cupsSideChannelDoRequest'>cupsSideChannelDoRequest()</a></h3>
<h4>Description</h4>
<p>Send a side-channel command to a backend and wait for a response.
-
-This function is normally only called by filters, drivers, or port
+<p>This function is normally only called by filters, drivers, or port
monitors in order to communicate with the backend used by the current
printer. Programs must be prepared to handle timeout or "not
implemented" status codes, which indicate that the backend or device
do not support the specified side-channel command.
-
-The "datalen" parameter must be initialized to the size of the buffer
+<p>The "datalen" parameter must be initialized to the size of the buffer
pointed to by the "data" parameter. cupsSideChannelDoRequest() will
update the value to contain the number of data bytes in the buffer.
-</p>
+
<h4>Syntax</h4>
-<pre>
-<a href='#cups_sc_status_t'>cups_sc_status_t</a>
+<p><tt>
+<a href='#cups_sc_status_t'>cups_sc_status_t</a><br>
cupsSideChannelDoRequest(
cups_sc_command_t command,
char * data,
int * datalen,
double timeout);
-</pre>
+</tt></p>
<h4>Arguments</h4>
-<div class='table'><table align='center' border='1' width='80%' cellpadding='5' cellspacing='0'>
+<div class='table'><table align='center' border='1' width='80%' cellpadding='5' cellspacing='0' summary='Arguments'>
<thead><tr><th>Name</th><th>Description</th></tr></thead>
<tbody>
<tr><td><tt>command</tt></td><td>Command to send</td></tr>
<h3 class='title'><span class='info'> CUPS 1.3 </span><a name='cupsSideChannelRead'>cupsSideChannelRead()</a></h3>
<h4>Description</h4>
<p>Read a side-channel message.
-
-This function is normally only called by backend programs to read
+<p>This function is normally only called by backend programs to read
commands from a filter, driver, or port monitor program. The
caller must be prepared to handle incomplete or invalid messages
and return the corresponding status codes.
-
-The "datalen" parameter must be initialized to the size of the buffer
+<p>The "datalen" parameter must be initialized to the size of the buffer
pointed to by the "data" parameter. cupsSideChannelDoRequest() will
update the value to contain the number of data bytes in the buffer.
-</p>
+
<h4>Syntax</h4>
-<pre>
-int
+<p><tt>
+int<br>
cupsSideChannelRead(
cups_sc_command_t * command,
<a href='#cups_sc_status_t'>cups_sc_status_t</a> * status,
char * data,
int * datalen,
double timeout);
-</pre>
+</tt></p>
<h4>Arguments</h4>
-<div class='table'><table align='center' border='1' width='80%' cellpadding='5' cellspacing='0'>
+<div class='table'><table align='center' border='1' width='80%' cellpadding='5' cellspacing='0' summary='Arguments'>
<thead><tr><th>Name</th><th>Description</th></tr></thead>
<tbody>
<tr><td><tt>command</tt></td><td>Command code</td></tr>
<h3 class='title'><span class='info'> CUPS 1.3 </span><a name='cupsSideChannelWrite'>cupsSideChannelWrite()</a></h3>
<h4>Description</h4>
<p>Write a side-channel message.
-
-This function is normally only called by backend programs to send
+<p>This function is normally only called by backend programs to send
responses to a filter, driver, or port monitor program.
-</p>
+
<h4>Syntax</h4>
-<pre>
-int
+<p><tt>
+int<br>
cupsSideChannelWrite(
cups_sc_command_t command,
<a href='#cups_sc_status_t'>cups_sc_status_t</a> status,
const char * data,
int datalen,
double timeout);
-</pre>
+</tt></p>
<h4>Arguments</h4>
-<div class='table'><table align='center' border='1' width='80%' cellpadding='5' cellspacing='0'>
+<div class='table'><table align='center' border='1' width='80%' cellpadding='5' cellspacing='0' summary='Arguments'>
<thead><tr><th>Name</th><th>Description</th></tr></thead>
<tbody>
<tr><td><tt>command</tt></td><td>Command code</td></tr>
projects / thirdparty / cups.git / blobdiff