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1 | <?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> |
2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" | |
3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> | |
4 | ||
5 | <!-- | |
572eb058 ZJS |
6 | SPDX-License-Identifier: LGPL-2.1+ |
7 | ||
dc83f27a LP |
8 | This file is part of systemd. |
9 | ||
10 | Copyright 2015 Lennart Poettering | |
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11 | --> |
12 | ||
13 | <refentry id="sd_event_source_set_userdata" xmlns:xi="http://www.w3.org/2001/XInclude"> | |
14 | ||
15 | <refentryinfo> | |
16 | <title>sd_event_source_set_userdata</title> | |
17 | <productname>systemd</productname> | |
18 | ||
19 | <authorgroup> | |
20 | <author> | |
21 | <contrib>Developer</contrib> | |
22 | <firstname>Lennart</firstname> | |
23 | <surname>Poettering</surname> | |
24 | <email>lennart@poettering.net</email> | |
25 | </author> | |
26 | </authorgroup> | |
27 | </refentryinfo> | |
28 | ||
29 | <refmeta> | |
30 | <refentrytitle>sd_event_source_set_userdata</refentrytitle> | |
31 | <manvolnum>3</manvolnum> | |
32 | </refmeta> | |
33 | ||
34 | <refnamediv> | |
35 | <refname>sd_event_source_set_userdata</refname> | |
36 | <refname>sd_event_source_get_userdata</refname> | |
37 | ||
38 | <refpurpose>Set or retrieve user data pointer of event sources</refpurpose> | |
39 | </refnamediv> | |
40 | ||
41 | <refsynopsisdiv> | |
42 | <funcsynopsis> | |
43 | <funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo> | |
44 | ||
45 | <funcprototype> | |
46 | <funcdef>void* <function>sd_event_source_set_userdata</function></funcdef> | |
47 | <paramdef>sd_event_source *<parameter>source</parameter></paramdef> | |
48 | <paramdef>void *<parameter>userdata</parameter></paramdef> | |
49 | </funcprototype> | |
50 | ||
51 | <funcprototype> | |
52 | <funcdef>void* <function>sd_event_source_get_userdata</function></funcdef> | |
53 | <paramdef>sd_event_source *<parameter>source</parameter></paramdef> | |
54 | </funcprototype> | |
55 | ||
56 | </funcsynopsis> | |
57 | </refsynopsisdiv> | |
58 | ||
59 | <refsect1> | |
60 | <title>Description</title> | |
61 | ||
62 | <para><function>sd_event_source_set_userdata()</function> may be | |
63 | used to set an arbitrary user data pointer for the event source | |
64 | object specified as <parameter>source</parameter>. The user data | |
65 | pointer is usually specified when creating an event source object | |
66 | with calls such as | |
67 | <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
68 | or | |
69 | <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
70 | and may be updated with this call. The user data pointer is also | |
71 | passed to all handler callback functions associated with the event | |
72 | source. The <parameter>userdata</parameter> parameter specifies | |
73 | the new user data pointer to set, the function returns the | |
74 | previous user data pointer. Note that <constant>NULL</constant> is | |
75 | a valid user data pointer.</para> | |
76 | ||
77 | <para><function>sd_event_source_get_userdata()</function> may be | |
78 | used to query the current user data pointer assigned to the event | |
79 | source object <parameter>source</parameter>.</para> | |
80 | </refsect1> | |
81 | ||
82 | <refsect1> | |
83 | <title>Return Value</title> | |
84 | ||
85 | <para>On success, | |
86 | <function>sd_event_source_set_userdata()</function> and | |
87 | <function>sd_event_source_get_userdata()</function> return the | |
88 | previously set user data pointer. On failure, they return | |
89 | NULL.</para> | |
90 | </refsect1> | |
91 | ||
92 | <xi:include href="libsystemd-pkgconfig.xml" /> | |
93 | ||
94 | <refsect1> | |
95 | <title>See Also</title> | |
96 | ||
97 | <para> | |
98 | <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
99 | <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
100 | <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
101 | <citerefentry><refentrytitle>sd_event_add_child</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
102 | <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
103 | <citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
104 | <citerefentry><refentrytitle>sd_event_source_set_description</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
105 | </para> | |
106 | </refsect1> | |
107 | ||
108 | </refentry> |