<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>udev</title> <meta name="generator" content="DocBook XSL Stylesheets V1.75.2"> <link rel="home" href="index.html" title="libudev Reference Manual"> <link rel="up" href="ch01.html" title="libudev"> <link rel="prev" href="ch01.html" title="libudev"> <link rel="next" href="libudev-udev-list.html" title="udev_list"> <meta name="generator" content="GTK-Doc V1.14 (XML mode)"> <link rel="stylesheet" href="style.css" type="text/css"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <table class="navigation" id="top" width="100%" summary="Navigation header" cellpadding="2" cellspacing="2"> <tr valign="middle"> <td><a accesskey="p" href="ch01.html"><img src="left.png" width="24" height="24" border="0" alt="Prev"></a></td> <td><a accesskey="u" href="ch01.html"><img src="up.png" width="24" height="24" border="0" alt="Up"></a></td> <td><a accesskey="h" href="index.html"><img src="home.png" width="24" height="24" border="0" alt="Home"></a></td> <th width="100%" align="center">libudev Reference Manual</th> <td><a accesskey="n" href="libudev-udev-list.html"><img src="right.png" width="24" height="24" border="0" alt="Next"></a></td> </tr> <tr><td colspan="5" class="shortcuts"> <a href="#libudev-udev.synopsis" class="shortcut">Top</a> | <a href="#libudev-udev.description" class="shortcut">Description</a> </td></tr> </table> <div class="refentry" title="udev"> <a name="libudev-udev"></a><div class="titlepage"></div> <div class="refnamediv"><table width="100%"><tr> <td valign="top"> <h2><span class="refentrytitle"><a name="libudev-udev.top_of_page"></a>udev</span></h2> <p>udev — libudev context</p> </td> <td valign="top" align="right"></td> </tr></table></div> <div class="refsynopsisdiv" title="Synopsis"> <a name="libudev-udev.synopsis"></a><h2>Synopsis</h2> <pre class="synopsis">struct <a class="link" href="libudev-udev.html#udev" title="struct udev">udev</a>; struct <a class="link" href="libudev-udev.html#udev" title="struct udev"><span class="returnvalue">udev</span></a> * <a class="link" href="libudev-udev.html#udev-ref" title="udev_ref ()">udev_ref</a> (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>); <span class="returnvalue">void</span> <a class="link" href="libudev-udev.html#udev-unref" title="udev_unref ()">udev_unref</a> (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>); struct <a class="link" href="libudev-udev.html#udev" title="struct udev"><span class="returnvalue">udev</span></a> * <a class="link" href="libudev-udev.html#udev-new" title="udev_new ()">udev_new</a> (<em class="parameter"><code><span class="type">void</span></code></em>); <span class="returnvalue">void</span> <a class="link" href="libudev-udev.html#udev-set-log-fn" title="udev_set_log_fn ()">udev_set_log_fn</a> (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>, <em class="parameter"><code><span class="type">void</span> (log_fnstruct udev *udev, int priority, const char *file, int line, const char *fn, const char *format, va_list args) ()</code></em>); <span class="returnvalue">int</span> <a class="link" href="libudev-udev.html#udev-get-log-priority" title="udev_get_log_priority ()">udev_get_log_priority</a> (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>); <span class="returnvalue">void</span> <a class="link" href="libudev-udev.html#udev-set-log-priority" title="udev_set_log_priority ()">udev_set_log_priority</a> (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>, <em class="parameter"><code><span class="type">int</span> priority</code></em>); const <span class="returnvalue">char</span> * <a class="link" href="libudev-udev.html#udev-get-sys-path" title="udev_get_sys_path ()">udev_get_sys_path</a> (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>); const <span class="returnvalue">char</span> * <a class="link" href="libudev-udev.html#udev-get-dev-path" title="udev_get_dev_path ()">udev_get_dev_path</a> (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>); <span class="returnvalue">void</span> * <a class="link" href="libudev-udev.html#udev-get-userdata" title="udev_get_userdata ()">udev_get_userdata</a> (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>); <span class="returnvalue">void</span> <a class="link" href="libudev-udev.html#udev-set-userdata" title="udev_set_userdata ()">udev_set_userdata</a> (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>, <em class="parameter"><code><span class="type">void</span> *userdata</code></em>); </pre> </div> <div class="refsect1" title="Description"> <a name="libudev-udev.description"></a><h2>Description</h2> <p> The context contains the default values read from the udev config file, and is passed to all library operations. </p> </div> <div class="refsect1" title="Details"> <a name="libudev-udev.details"></a><h2>Details</h2> <div class="refsect2" title="struct udev"> <a name="udev"></a><h3>struct udev</h3> <pre class="programlisting">struct udev;</pre> <p> Opaque object representing the library context. </p> </div> <hr> <div class="refsect2" title="udev_ref ()"> <a name="udev-ref"></a><h3>udev_ref ()</h3> <pre class="programlisting">struct <a class="link" href="libudev-udev.html#udev" title="struct udev"><span class="returnvalue">udev</span></a> * udev_ref (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>);</pre> <p> Take a reference of the udev library context. </p> <div class="variablelist"><table border="0"> <col align="left" valign="top"> <tbody> <tr> <td><p><span class="term"><em class="parameter"><code>udev</code></em> :</span></p></td> <td>udev library context </td> </tr> <tr> <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> <td> the passed udev library context </td> </tr> </tbody> </table></div> </div> <hr> <div class="refsect2" title="udev_unref ()"> <a name="udev-unref"></a><h3>udev_unref ()</h3> <pre class="programlisting"><span class="returnvalue">void</span> udev_unref (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>);</pre> <p> Drop a reference of the udev library context. If the refcount reaches zero, the resources of the context will be released. </p> <div class="variablelist"><table border="0"> <col align="left" valign="top"> <tbody><tr> <td><p><span class="term"><em class="parameter"><code>udev</code></em> :</span></p></td> <td>udev library context </td> </tr></tbody> </table></div> </div> <hr> <div class="refsect2" title="udev_new ()"> <a name="udev-new"></a><h3>udev_new ()</h3> <pre class="programlisting">struct <a class="link" href="libudev-udev.html#udev" title="struct udev"><span class="returnvalue">udev</span></a> * udev_new (<em class="parameter"><code><span class="type">void</span></code></em>);</pre> <p> Create udev library context. This reads the udev configuration file, and fills in the default values. </p> <p> The initial refcount is 1, and needs to be decremented to release the resources of the udev library context. </p> <div class="variablelist"><table border="0"> <col align="left" valign="top"> <tbody><tr> <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> <td> a new udev library context </td> </tr></tbody> </table></div> </div> <hr> <div class="refsect2" title="udev_set_log_fn ()"> <a name="udev-set-log-fn"></a><h3>udev_set_log_fn ()</h3> <pre class="programlisting"><span class="returnvalue">void</span> udev_set_log_fn (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>, <em class="parameter"><code><span class="type">void</span> (log_fnstruct udev *udev, int priority, const char *file, int line, const char *fn, const char *format, va_list args) ()</code></em>);</pre> <p> The built-in logging writes to stderr. It can be overridden by a custom function, to plug log messages into the users' logging functionality. </p> <div class="variablelist"><table border="0"> <col align="left" valign="top"> <tbody><tr> <td><p><span class="term"><em class="parameter"><code>udev</code></em> :</span></p></td> <td>udev library context </td> </tr></tbody> </table></div> </div> <hr> <div class="refsect2" title="udev_get_log_priority ()"> <a name="udev-get-log-priority"></a><h3>udev_get_log_priority ()</h3> <pre class="programlisting"><span class="returnvalue">int</span> udev_get_log_priority (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>);</pre> <p> The initial logging priority is read from the udev config file at startup. </p> <div class="variablelist"><table border="0"> <col align="left" valign="top"> <tbody> <tr> <td><p><span class="term"><em class="parameter"><code>udev</code></em> :</span></p></td> <td>udev library context </td> </tr> <tr> <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> <td> the current logging priority </td> </tr> </tbody> </table></div> </div> <hr> <div class="refsect2" title="udev_set_log_priority ()"> <a name="udev-set-log-priority"></a><h3>udev_set_log_priority ()</h3> <pre class="programlisting"><span class="returnvalue">void</span> udev_set_log_priority (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>, <em class="parameter"><code><span class="type">int</span> priority</code></em>);</pre> <p> Set the current logging priority. The value controls which messages are logged. </p> <div class="variablelist"><table border="0"> <col align="left" valign="top"> <tbody> <tr> <td><p><span class="term"><em class="parameter"><code>udev</code></em> :</span></p></td> <td>udev library context </td> </tr> <tr> <td><p><span class="term"><em class="parameter"><code>priority</code></em> :</span></p></td> <td>the new logging priority </td> </tr> </tbody> </table></div> </div> <hr> <div class="refsect2" title="udev_get_sys_path ()"> <a name="udev-get-sys-path"></a><h3>udev_get_sys_path ()</h3> <pre class="programlisting">const <span class="returnvalue">char</span> * udev_get_sys_path (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>);</pre> <p> Retrieve the sysfs mount point. The default is "/sys". For testing purposes, it can be overridden with the environment variable SYSFS_PATH. </p> <div class="variablelist"><table border="0"> <col align="left" valign="top"> <tbody> <tr> <td><p><span class="term"><em class="parameter"><code>udev</code></em> :</span></p></td> <td>udev library context </td> </tr> <tr> <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> <td> the sys mount point </td> </tr> </tbody> </table></div> </div> <hr> <div class="refsect2" title="udev_get_dev_path ()"> <a name="udev-get-dev-path"></a><h3>udev_get_dev_path ()</h3> <pre class="programlisting">const <span class="returnvalue">char</span> * udev_get_dev_path (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>);</pre> <p> Retrieve the device directory path. The default value is "/dev", the actual value may be overridden in the udev configuration file. </p> <div class="variablelist"><table border="0"> <col align="left" valign="top"> <tbody> <tr> <td><p><span class="term"><em class="parameter"><code>udev</code></em> :</span></p></td> <td>udev library context </td> </tr> <tr> <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> <td> the device directory path </td> </tr> </tbody> </table></div> </div> <hr> <div class="refsect2" title="udev_get_userdata ()"> <a name="udev-get-userdata"></a><h3>udev_get_userdata ()</h3> <pre class="programlisting"><span class="returnvalue">void</span> * udev_get_userdata (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>);</pre> <p> Retrieve stored data pointer from library context. This might be useful to access from callbacks like a custom logging function. </p> <div class="variablelist"><table border="0"> <col align="left" valign="top"> <tbody> <tr> <td><p><span class="term"><em class="parameter"><code>udev</code></em> :</span></p></td> <td>udev library context </td> </tr> <tr> <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td> <td> stored userdata </td> </tr> </tbody> </table></div> </div> <hr> <div class="refsect2" title="udev_set_userdata ()"> <a name="udev-set-userdata"></a><h3>udev_set_userdata ()</h3> <pre class="programlisting"><span class="returnvalue">void</span> udev_set_userdata (<em class="parameter"><code><span class="type">struct udev</span> *udev</code></em>, <em class="parameter"><code><span class="type">void</span> *userdata</code></em>);</pre> <p> Store custom <em class="parameter"><code>userdata</code></em> in the library context. </p> <div class="variablelist"><table border="0"> <col align="left" valign="top"> <tbody> <tr> <td><p><span class="term"><em class="parameter"><code>udev</code></em> :</span></p></td> <td>udev library context </td> </tr> <tr> <td><p><span class="term"><em class="parameter"><code>userdata</code></em> :</span></p></td> <td>data pointer </td> </tr> </tbody> </table></div> </div> </div> </div> <div class="footer"> <hr> Generated by GTK-Doc V1.14</div> </body> </html>