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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 | <!-- | |
6 | This file is part of systemd. | |
7 | ||
8 | Copyright 2015 Lennart Poettering | |
9 | ||
10 | systemd is free software; you can redistribute it and/or modify it | |
11 | under the terms of the GNU Lesser General Public License as published by | |
12 | the Free Software Foundation; either version 2.1 of the License, or | |
13 | (at your option) any later version. | |
14 | ||
15 | systemd is distributed in the hope that it will be useful, but | |
16 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
18 | Lesser General Public License for more details. | |
19 | ||
20 | You should have received a copy of the GNU Lesser General Public License | |
21 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
22 | --> | |
23 | ||
24 | <refentry id="sd_event_source_set_userdata" xmlns:xi="http://www.w3.org/2001/XInclude"> | |
25 | ||
26 | <refentryinfo> | |
27 | <title>sd_event_source_set_userdata</title> | |
28 | <productname>systemd</productname> | |
29 | ||
30 | <authorgroup> | |
31 | <author> | |
32 | <contrib>Developer</contrib> | |
33 | <firstname>Lennart</firstname> | |
34 | <surname>Poettering</surname> | |
35 | <email>lennart@poettering.net</email> | |
36 | </author> | |
37 | </authorgroup> | |
38 | </refentryinfo> | |
39 | ||
40 | <refmeta> | |
41 | <refentrytitle>sd_event_source_set_userdata</refentrytitle> | |
42 | <manvolnum>3</manvolnum> | |
43 | </refmeta> | |
44 | ||
45 | <refnamediv> | |
46 | <refname>sd_event_source_set_userdata</refname> | |
47 | <refname>sd_event_source_get_userdata</refname> | |
48 | ||
49 | <refpurpose>Set or retrieve user data pointer of event sources</refpurpose> | |
50 | </refnamediv> | |
51 | ||
52 | <refsynopsisdiv> | |
53 | <funcsynopsis> | |
54 | <funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo> | |
55 | ||
56 | <funcprototype> | |
57 | <funcdef>void* <function>sd_event_source_set_userdata</function></funcdef> | |
58 | <paramdef>sd_event_source *<parameter>source</parameter></paramdef> | |
59 | <paramdef>void *<parameter>userdata</parameter></paramdef> | |
60 | </funcprototype> | |
61 | ||
62 | <funcprototype> | |
63 | <funcdef>void* <function>sd_event_source_get_userdata</function></funcdef> | |
64 | <paramdef>sd_event_source *<parameter>source</parameter></paramdef> | |
65 | </funcprototype> | |
66 | ||
67 | </funcsynopsis> | |
68 | </refsynopsisdiv> | |
69 | ||
70 | <refsect1> | |
71 | <title>Description</title> | |
72 | ||
73 | <para><function>sd_event_source_set_userdata()</function> may be | |
74 | used to set an arbitrary user data pointer for the event source | |
75 | object specified as <parameter>source</parameter>. The user data | |
76 | pointer is usually specified when creating an event source object | |
77 | with calls such as | |
78 | <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
79 | or | |
80 | <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
81 | and may be updated with this call. The user data pointer is also | |
82 | passed to all handler callback functions associated with the event | |
83 | source. The <parameter>userdata</parameter> parameter specifies | |
84 | the new user data pointer to set, the function returns the | |
85 | previous user data pointer. Note that <constant>NULL</constant> is | |
86 | a valid user data pointer.</para> | |
87 | ||
88 | <para><function>sd_event_source_get_userdata()</function> may be | |
89 | used to query the current user data pointer assigned to the event | |
90 | source object <parameter>source</parameter>.</para> | |
91 | </refsect1> | |
92 | ||
93 | <refsect1> | |
94 | <title>Return Value</title> | |
95 | ||
96 | <para>On success, | |
97 | <function>sd_event_source_set_userdata()</function> and | |
98 | <function>sd_event_source_get_userdata()</function> return the | |
99 | previously set user data pointer. On failure, they return | |
100 | NULL.</para> | |
101 | </refsect1> | |
102 | ||
103 | <xi:include href="libsystemd-pkgconfig.xml" /> | |
104 | ||
105 | <refsect1> | |
106 | <title>See Also</title> | |
107 | ||
108 | <para> | |
109 | <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
110 | <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
111 | <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
112 | <citerefentry><refentrytitle>sd_event_add_child</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
113 | <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
114 | <citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
115 | <citerefentry><refentrytitle>sd_event_source_set_description</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
116 | </para> | |
117 | </refsect1> | |
118 | ||
119 | </refentry> |