man/libudev.xml

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   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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   7 <!-- SPDX-License-Identifier: LGPL-2.1+ -->
   8
   9 <refentry id="libudev"
  10   xmlns:xi="http://www.w3.org/2001/XInclude">
  11
  12   <refentryinfo>
  13     <title>libudev</title>
  14     <productname>systemd</productname>
  15   </refentryinfo>
  16
  17   <refmeta>
  18     <refentrytitle>libudev</refentrytitle>
  19     <manvolnum>3</manvolnum>
  20   </refmeta>
  21
  22   <refnamediv>
  23     <refname>libudev</refname>
  24     <refpurpose>API for enumerating and introspecting local devices</refpurpose>
  25   </refnamediv>
  26
  27   <refsynopsisdiv>
  28     <funcsynopsis>
  29       <funcsynopsisinfo>#include &lt;libudev.h&gt;</funcsynopsisinfo>
  30     </funcsynopsis>
  31
  32     <cmdsynopsis>
  33       <command>pkg-config --cflags --libs libudev</command>
  34     </cmdsynopsis>
  35   </refsynopsisdiv>
  36
  37   <refsect1>
  38     <title>Description</title>
  39
  40     <para><filename>libudev.h</filename> provides APIs to introspect
  41     and enumerate devices on the local system.</para>
  42
  43     <para>All functions require a libudev context to operate. This
  44     context can be create via
  45     <citerefentry><refentrytitle>udev_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
  46     It is used to track library state and link objects together. No
  47     global state is used by libudev, everything is always linked to
  48     a udev context.</para>
  49
  50     <xi:include href="threads-aware.xml" xpointer="strict"/>
  51
  52     <para>To introspect a local device on a system, a udev device
  53     object can be created via
  54     <citerefentry><refentrytitle>udev_device_new_from_syspath</refentrytitle><manvolnum>3</manvolnum></citerefentry>
  55     and friends. The device object allows one to query current state,
  56     read and write attributes and lookup properties of the device in
  57     question.</para>
  58
  59     <para>To enumerate local devices on the system, an enumeration
  60     object can be created via
  61     <citerefentry><refentrytitle>udev_enumerate_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
  62
  63     <para>To monitor the local system for hotplugged or unplugged
  64     devices, a monitor can be created via
  65     <citerefentry><refentrytitle>udev_monitor_new_from_netlink</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
  66
  67     <para>Whenever libudev returns a list of objects, the
  68     <citerefentry><refentrytitle>udev_list_entry</refentrytitle><manvolnum>3</manvolnum></citerefentry>
  69     API should be used to iterate, access and modify those lists.</para>
  70
  71     <para>Furthermore, libudev also exports legacy APIs that should
  72     not be used by new software (and as such are not documented as
  73     part of this manual). This includes the hardware database known
  74     as <constant>udev_hwdb</constant> (please use the new
  75     <citerefentry><refentrytitle>sd-hwdb</refentrytitle><manvolnum>3</manvolnum></citerefentry>
  76     API instead) and the <constant>udev_queue</constant> object to
  77     query the udev daemon (which should not be used by new software
  78     at all).</para>
  79   </refsect1>
  80
  81   <refsect1>
  82     <title>See Also</title>
  83     <para>
  84       <citerefentry><refentrytitle>udev_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
  85       <citerefentry><refentrytitle>udev_device_new_from_syspath</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
  86       <citerefentry><refentrytitle>udev_enumerate_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
  87       <citerefentry><refentrytitle>udev_monitor_new_from_netlink</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
  88       <citerefentry><refentrytitle>udev_list_entry</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
  89       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  90       <citerefentry><refentrytitle>sd-device</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
  91       <citerefentry><refentrytitle>sd-hwdb</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
  92       <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  93     </para>
  94   </refsect1>
  95
  96 </refentry>