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1 | <?xml version='1.0'?> <!--*-nxml-*--> |
2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" | |
3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [ | |
4 | <!ENTITY % entities SYSTEM "custom-entities.ent" > | |
5 | %entities; | |
6 | ]> | |
7 | ||
8 | <!-- | |
572eb058 ZJS |
9 | SPDX-License-Identifier: LGPL-2.1+ |
10 | ||
96b2fb93 | 11 | Copyright © 2015 David Herrmann <dh.herrmann@gmail.com> |
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12 | --> |
13 | ||
14 | <refentry id="libudev" | |
15 | xmlns:xi="http://www.w3.org/2001/XInclude"> | |
16 | ||
17 | <refentryinfo> | |
18 | <title>libudev</title> | |
19 | <productname>systemd</productname> | |
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20 | </refentryinfo> |
21 | ||
22 | <refmeta> | |
23 | <refentrytitle>libudev</refentrytitle> | |
24 | <manvolnum>3</manvolnum> | |
25 | </refmeta> | |
26 | ||
27 | <refnamediv> | |
28 | <refname>libudev</refname> | |
29 | <refpurpose>API for enumerating and introspecting local devices</refpurpose> | |
30 | </refnamediv> | |
31 | ||
32 | <refsynopsisdiv> | |
33 | <funcsynopsis> | |
34 | <funcsynopsisinfo>#include <libudev.h></funcsynopsisinfo> | |
35 | </funcsynopsis> | |
36 | ||
37 | <cmdsynopsis> | |
38 | <command>pkg-config --cflags --libs libudev</command> | |
39 | </cmdsynopsis> | |
40 | </refsynopsisdiv> | |
41 | ||
42 | <refsect1> | |
43 | <title>Description</title> | |
44 | ||
45 | <para><filename>libudev.h</filename> provides APIs to introspect | |
46 | and enumerate devices on the local system.</para> | |
47 | ||
48 | <para>All functions require a libudev context to operate. This | |
49 | context can be create via | |
50 | <citerefentry><refentrytitle>udev_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
51 | It is used to track library state and link objects together. No | |
52 | global state is used by libudev, everything is always linked to | |
53 | a udev context. Furthermore, multiple different udev contexts can | |
54 | be used in parallel by multiple threads. However, a single context | |
55 | must not be accessed by multiple threads in parallel. The caller | |
a8eaaee7 | 56 | is responsible for providing suitable locking if they intend to use |
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57 | it from multiple threads.</para> |
58 | ||
59 | <para>To introspect a local device on a system, a udev device | |
60 | object can be created via | |
61 | <citerefentry><refentrytitle>udev_device_new_from_syspath</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
595bfe7d | 62 | and friends. The device object allows one to query current state, |
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63 | read and write attributes and lookup properties of the device in |
64 | question.</para> | |
65 | ||
66 | <para>To enumerate local devices on the system, an enumeration | |
67 | object can be created via | |
68 | <citerefentry><refentrytitle>udev_enumerate_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para> | |
69 | ||
70 | <para>To monitor the local system for hotplugged or unplugged | |
71 | devices, a monitor can be created via | |
72 | <citerefentry><refentrytitle>udev_monitor_new_from_netlink</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para> | |
73 | ||
74 | <para>Whenever libudev returns a list of objects, the | |
75 | <citerefentry><refentrytitle>udev_list_entry</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
76 | API should be used to iterate, access and modify those lists.</para> | |
77 | ||
78 | <para>Furthermore, libudev also exports legacy APIs that should | |
79 | not be used by new software (and as such are not documented as | |
b938cb90 | 80 | part of this manual). This includes the hardware database known |
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81 | as <constant>udev_hwdb</constant> (please use the new |
82 | <citerefentry><refentrytitle>sd-hwdb</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
83 | API instead) and the <constant>udev_queue</constant> object to | |
b938cb90 | 84 | query the udev daemon (which should not be used by new software |
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85 | at all).</para> |
86 | </refsect1> | |
87 | ||
88 | <refsect1> | |
89 | <title>See Also</title> | |
90 | <para> | |
91 | <citerefentry><refentrytitle>udev_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
92 | <citerefentry><refentrytitle>udev_device_new_from_syspath</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
93 | <citerefentry><refentrytitle>udev_enumerate_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
94 | <citerefentry><refentrytitle>udev_monitor_new_from_netlink</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
95 | <citerefentry><refentrytitle>udev_list_entry</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
96 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
97 | <citerefentry><refentrytitle>sd-device</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
98 | <citerefentry><refentrytitle>sd-hwdb</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
99 | <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
100 | </para> | |
101 | </refsect1> | |
102 | ||
103 | </refentry> |