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514094f9 | 1 | <?xml version='1.0'?> |
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2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> | |
0307f791 | 4 | <!-- SPDX-License-Identifier: LGPL-2.1+ --> |
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5 | |
6 | <refentry id="sd_event_source_set_userdata" xmlns:xi="http://www.w3.org/2001/XInclude"> | |
7 | ||
8 | <refentryinfo> | |
9 | <title>sd_event_source_set_userdata</title> | |
10 | <productname>systemd</productname> | |
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11 | </refentryinfo> |
12 | ||
13 | <refmeta> | |
14 | <refentrytitle>sd_event_source_set_userdata</refentrytitle> | |
15 | <manvolnum>3</manvolnum> | |
16 | </refmeta> | |
17 | ||
18 | <refnamediv> | |
19 | <refname>sd_event_source_set_userdata</refname> | |
20 | <refname>sd_event_source_get_userdata</refname> | |
21 | ||
22 | <refpurpose>Set or retrieve user data pointer of event sources</refpurpose> | |
23 | </refnamediv> | |
24 | ||
25 | <refsynopsisdiv> | |
26 | <funcsynopsis> | |
27 | <funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo> | |
28 | ||
29 | <funcprototype> | |
30 | <funcdef>void* <function>sd_event_source_set_userdata</function></funcdef> | |
31 | <paramdef>sd_event_source *<parameter>source</parameter></paramdef> | |
32 | <paramdef>void *<parameter>userdata</parameter></paramdef> | |
33 | </funcprototype> | |
34 | ||
35 | <funcprototype> | |
36 | <funcdef>void* <function>sd_event_source_get_userdata</function></funcdef> | |
37 | <paramdef>sd_event_source *<parameter>source</parameter></paramdef> | |
38 | </funcprototype> | |
39 | ||
40 | </funcsynopsis> | |
41 | </refsynopsisdiv> | |
42 | ||
43 | <refsect1> | |
44 | <title>Description</title> | |
45 | ||
46 | <para><function>sd_event_source_set_userdata()</function> may be | |
47 | used to set an arbitrary user data pointer for the event source | |
48 | object specified as <parameter>source</parameter>. The user data | |
49 | pointer is usually specified when creating an event source object | |
50 | with calls such as | |
51 | <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
52 | or | |
53 | <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
54 | and may be updated with this call. The user data pointer is also | |
55 | passed to all handler callback functions associated with the event | |
56 | source. The <parameter>userdata</parameter> parameter specifies | |
57 | the new user data pointer to set, the function returns the | |
58 | previous user data pointer. Note that <constant>NULL</constant> is | |
59 | a valid user data pointer.</para> | |
60 | ||
61 | <para><function>sd_event_source_get_userdata()</function> may be | |
62 | used to query the current user data pointer assigned to the event | |
63 | source object <parameter>source</parameter>.</para> | |
64 | </refsect1> | |
65 | ||
66 | <refsect1> | |
67 | <title>Return Value</title> | |
68 | ||
69 | <para>On success, | |
70 | <function>sd_event_source_set_userdata()</function> and | |
71 | <function>sd_event_source_get_userdata()</function> return the | |
72 | previously set user data pointer. On failure, they return | |
73 | NULL.</para> | |
74 | </refsect1> | |
75 | ||
76 | <xi:include href="libsystemd-pkgconfig.xml" /> | |
77 | ||
78 | <refsect1> | |
79 | <title>See Also</title> | |
80 | ||
81 | <para> | |
82 | <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
83 | <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
84 | <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
dc83f27a | 85 | <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
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86 | <citerefentry><refentrytitle>sd_event_add_child</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
87 | <citerefentry><refentrytitle>sd_event_add_inotify</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
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88 | <citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
89 | <citerefentry><refentrytitle>sd_event_source_set_description</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
90 | </para> | |
91 | </refsect1> | |
92 | ||
93 | </refentry> |