1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
|
<?xml version='1.0'?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1+ -->
<refentry id="sd_event_source_unref" xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd_event_source_unref</title>
<productname>elogind</productname>
</refentryinfo>
<refmeta>
<refentrytitle>sd_event_source_unref</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_event_source_unref</refname>
<refname>sd_event_source_unrefp</refname>
<refname>sd_event_source_ref</refname>
<refname>sd_event_source_disable_unref</refname>
<refname>sd_event_source_disable_unrefp</refname>
<refpurpose>Increase or decrease event source reference counters</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include <elogind/sd-event.h></funcsynopsisinfo>
<funcprototype>
<funcdef>sd_event_source* <function>sd_event_source_unref</function></funcdef>
<paramdef>sd_event_source *<parameter>source</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>void <function>sd_event_source_unrefp</function></funcdef>
<paramdef>sd_event_source **<parameter>source</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>sd_event_source* <function>sd_event_source_ref</function></funcdef>
<paramdef>sd_event_source *<parameter>source</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>sd_event_source* <function>sd_event_source_disable_unref</function></funcdef>
<paramdef>sd_event_source *<parameter>source</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>void <function>sd_event_source_disable_unrefp</function></funcdef>
<paramdef>sd_event_source **<parameter>source</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><function>sd_event_source_unref()</function> may be used to
decrement by one the reference counter of the event source object
specified as <parameter>source</parameter>. The reference counter
is initially set to one, when the event source is created with calls
such as
<citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>
or
<citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>. When
the reference counter reaches zero it is removed from its event loop
object and destroyed.</para>
<para><function>sd_event_source_unrefp()</function> is similar to
<function>sd_event_source_unref()</function> but takes a pointer to a
pointer to an <type>sd_event_source</type> object. This call is useful in
conjunction with GCC's and LLVM's <ulink
url="https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html">Clean-up
Variable Attribute</ulink>. Note that this function is defined as
inline function.</para>
<para><function>sd_event_source_ref()</function> may be used
to increase by one the reference counter of the event source object
specified as <parameter>source</parameter>.</para>
<para><function>sd_event_source_unref()</function>,
<function>sd_bus_creds_unrefp()</function> and
<function>sd_bus_creds_ref()</function> execute no operation if
the passed event source object is
<constant>NULL</constant>.</para>
<para>Note that event source objects stay alive and may be dispatched as long as they have a reference
counter greater than zero. In order to drop a reference of an event source and make sure the associated
event source handler function is not called anymore it is recommended to combine a call of
<function>sd_event_source_unref()</function> with a prior call to
<function>sd_event_source_set_enabled()</function> with <constant>SD_EVENT_OFF</constant> or call
<function>sd_event_source_disable_unref()</function>, see below.</para>
<para><function>sd_event_source_disable_unref()</function> combines a call to
<function>sd_event_source_set_enabled()</function> with <constant>SD_EVENT_OFF</constant> with
<function>sd_event_source_unref()</function>. This ensures that the source is disabled before the local
reference to it is lost. The <parameter>source</parameter> parameter is allowed to be
<constant>NULL</constant>.</para>
<para><function>sd_event_source_disable_unrefp()</function> is similar to
<function>sd_event_source_unrefp()</function>, but in addition disables the source first. This call is
useful in conjunction with GCC's and LLVM's
<ulink url="https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html">Clean-up Variable
Attribute</ulink>. Note that this function is defined as inline function.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para><function>sd_event_source_unref()</function> and
<function>sd_event_source_disable_unref()</function> always return <constant>NULL</constant>.
<function>sd_event_source_ref()</function> always returns the event source object passed in.</para>
</refsect1>
<xi:include href="libelogind-pkgconfig.xml" />
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_event_add_child</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_event_add_inotify</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_event_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
|
