]>
Commit | Line | Data |
---|---|---|
514094f9 | 1 | <?xml version='1.0'?> |
15723a1d LP |
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 | <!-- SPDX-License-Identifier: LGPL-2.1+ --> | |
6 | ||
7 | <refentry id="sd_event_source_set_destroy_callback" | |
8 | xmlns:xi="http://www.w3.org/2001/XInclude"> | |
9 | ||
10 | <refentryinfo> | |
11 | <title>sd_event_source_set_destroy_callback</title> | |
12 | <productname>systemd</productname> | |
13 | </refentryinfo> | |
14 | ||
15 | <refmeta> | |
16 | <refentrytitle>sd_event_source_set_destroy_callback</refentrytitle> | |
17 | <manvolnum>3</manvolnum> | |
18 | </refmeta> | |
19 | ||
20 | <refnamediv> | |
21 | <refname>sd_event_source_set_destroy_callback</refname> | |
22 | <refname>sd_event_source_get_destroy_callback</refname> | |
23 | <refname>sd_event_destroy_t</refname> | |
24 | ||
25 | <refpurpose>Define the callback function for resource cleanup.</refpurpose> | |
26 | </refnamediv> | |
27 | ||
28 | <refsynopsisdiv> | |
29 | <funcsynopsis> | |
30 | <funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo> | |
31 | ||
32 | <funcprototype> | |
33 | <funcdef>typedef int (*<function>sd_event_destroy_t</function>)</funcdef> | |
34 | <paramdef>void *<parameter>userdata</parameter></paramdef> | |
35 | </funcprototype> | |
36 | ||
37 | <funcprototype> | |
38 | <funcdef>int <function>sd_event_source_set_destroy_callback</function></funcdef> | |
39 | <paramdef>sd_event_source *<parameter>source</parameter></paramdef> | |
40 | <paramdef>sd_event_destroy_t <parameter>callback</parameter></paramdef> | |
41 | </funcprototype> | |
42 | ||
43 | <funcprototype> | |
44 | <funcdef>int <function>sd_event_source_get_destroy_callback</function></funcdef> | |
45 | <paramdef>sd_event_source *<parameter>source</parameter></paramdef> | |
46 | <paramdef>sd_event_destroy_t *<parameter>callback</parameter></paramdef> | |
47 | </funcprototype> | |
48 | ||
49 | </funcsynopsis> | |
50 | </refsynopsisdiv> | |
51 | ||
52 | <refsect1> | |
53 | <title>Description</title> | |
54 | ||
55 | <para><function>sd_event_source_set_destroy_callback()</function> sets <parameter>callback</parameter> as the | |
56 | callback function to be called right before the event source object <parameter>source</parameter> is | |
57 | deallocated. The <parameter>userdata</parameter> pointer from the event source object will be passed as the | |
58 | <parameter>userdata</parameter> parameter. This pointer can be set by an argument to the constructor functions, see | |
59 | <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, or directly, | |
60 | see | |
61 | <citerefentry><refentrytitle>sd_event_source_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
62 | This callback function is called even if <parameter>userdata</parameter> is <constant>NULL</constant>. Note that | |
63 | this callback is invoked at a time where the event source object itself is already invalidated, and executing | |
64 | operations or taking new references to the event source object is not permissible.</para> | |
65 | ||
66 | <para><function>sd_event_source_get_destroy_callback()</function> returns the current callback | |
67 | for <parameter>source</parameter> in the <parameter>callback</parameter> parameter.</para> | |
68 | </refsect1> | |
69 | ||
70 | <refsect1> | |
71 | <title>Return Value</title> | |
72 | ||
73 | <para>On success, <function>sd_event_source_set_destroy_callback()</function> returns 0 or a positive integer. On | |
74 | failure, it returns a negative errno-style error code.</para> | |
75 | ||
76 | <para><function>sd_event_source_get_destroy_callback()</function> returns positive if the destroy callback function | |
77 | is set, 0 if not. On failure, returns a negative errno-style error code.</para> | |
78 | </refsect1> | |
79 | ||
80 | <refsect1> | |
81 | <title>Errors</title> | |
82 | ||
83 | <para>Returned errors may indicate the following problems:</para> | |
84 | ||
85 | <variablelist> | |
86 | <varlistentry> | |
87 | <term><constant>-EINVAL</constant></term> | |
88 | ||
89 | <listitem><para>The <parameter>source</parameter> parameter is <constant>NULL</constant>.</para></listitem> | |
90 | </varlistentry> | |
91 | </variablelist> | |
92 | </refsect1> | |
93 | ||
94 | <xi:include href="libsystemd-pkgconfig.xml" /> | |
95 | ||
96 | <refsect1> | |
97 | <title>See Also</title> | |
98 | ||
99 | <para> | |
100 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
101 | <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
102 | <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
103 | <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
104 | <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
105 | <citerefentry><refentrytitle>sd_event_add_child</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
106 | <citerefentry><refentrytitle>sd_event_add_inotify</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
107 | <citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
108 | <citerefentry><refentrytitle>sd_event_source_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
109 | </para> | |
110 | </refsect1> | |
111 | ||
112 | </refentry> |