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">
6 This file is part of elogind.
7 SPDX-License-Identifier: LGPL-2.1+
10 Copyright 2015 Lennart Poettering
13 <refentry id="sd_event_source_set_userdata" xmlns:xi="http://www.w3.org/2001/XInclude">
16 <title>sd_event_source_set_userdata</title>
17 <productname>elogind</productname>
21 <contrib>Developer</contrib>
22 <firstname>Lennart</firstname>
23 <surname>Poettering</surname>
24 <email>lennart@poettering.net</email>
30 <refentrytitle>sd_event_source_set_userdata</refentrytitle>
31 <manvolnum>3</manvolnum>
35 <refname>sd_event_source_set_userdata</refname>
36 <refname>sd_event_source_get_userdata</refname>
38 <refpurpose>Set or retrieve user data pointer of event sources</refpurpose>
43 <funcsynopsisinfo>#include <elogind/sd-event.h></funcsynopsisinfo>
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>
52 <funcdef>void* <function>sd_event_source_get_userdata</function></funcdef>
53 <paramdef>sd_event_source *<parameter>source</parameter></paramdef>
60 <title>Description</title>
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
67 <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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>
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>
83 <title>Return Value</title>
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
92 <xi:include href="libelogind-pkgconfig.xml" />
95 <title>See Also</title>
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>