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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" | |
12b42c76 | 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
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4 | |
5 | <!-- | |
572eb058 | 6 | SPDX-License-Identifier: LGPL-2.1+ |
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7 | --> |
8 | ||
dc83f27a | 9 | <refentry id="sd_event_run" xmlns:xi="http://www.w3.org/2001/XInclude"> |
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10 | |
11 | <refentryinfo> | |
12 | <title>sd_event_run</title> | |
13 | <productname>systemd</productname> | |
14 | ||
15 | <authorgroup> | |
16 | <author> | |
17 | <contrib>Developer</contrib> | |
18 | <firstname>Tom</firstname> | |
19 | <surname>Gundersen</surname> | |
20 | <email>teg@jklm.no</email> | |
21 | </author> | |
22 | </authorgroup> | |
23 | </refentryinfo> | |
24 | ||
25 | <refmeta> | |
26 | <refentrytitle>sd_event_run</refentrytitle> | |
27 | <manvolnum>3</manvolnum> | |
28 | </refmeta> | |
29 | ||
30 | <refnamediv> | |
31 | <refname>sd_event_run</refname> | |
32 | <refname>sd_event_loop</refname> | |
33 | ||
dc83f27a | 34 | <refpurpose>Run an event loop</refpurpose> |
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35 | </refnamediv> |
36 | ||
37 | <refsynopsisdiv> | |
38 | <funcsynopsis> | |
39 | <funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo> | |
40 | ||
41 | <funcprototype> | |
42 | <funcdef>int <function>sd_event_run</function></funcdef> | |
43 | <paramdef>sd_event *<parameter>event</parameter></paramdef> | |
dc83f27a | 44 | <paramdef>uint64_t <parameter>usec</parameter></paramdef> |
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45 | </funcprototype> |
46 | ||
47 | <funcprototype> | |
48 | <funcdef>int <function>sd_event_loop</function></funcdef> | |
49 | <paramdef>sd_event *<parameter>event</parameter></paramdef> | |
50 | </funcprototype> | |
51 | </funcsynopsis> | |
52 | </refsynopsisdiv> | |
53 | ||
54 | <refsect1> | |
55 | <title>Description</title> | |
56 | ||
dc83f27a LP |
57 | <para><function>sd_event_run()</function> may be used to run a single |
58 | iteration of the event loop specified in the | |
59 | <parameter>event</parameter> parameter. The function waits until an event to | |
60 | process is available, and dispatches the registered handler for | |
61 | it. The <parameter>usec</parameter> parameter specifies the | |
62 | maximum time (in microseconds) to wait for an event. Use | |
63 | <constant>(uint64_t) -1</constant> to specify an infinite | |
64 | timeout.</para> | |
65 | ||
66 | <para><function>sd_event_loop()</function> invokes | |
67 | <function>sd_event_run()</function> in a loop, thus implementing | |
68 | the actual event loop. The call returns as soon as exiting was | |
69 | requested using | |
70 | <citerefentry><refentrytitle>sd_event_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para> | |
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71 | |
72 | <para>The event loop object <parameter>event</parameter> is | |
73 | created with | |
dc83f27a LP |
74 | <citerefentry><refentrytitle>sd_event_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>. |
75 | Events sources to wait for and their handlers may be registered | |
76 | with | |
77 | <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
78 | <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
79 | <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
80 | <citerefentry><refentrytitle>sd_event_add_child</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
81 | <citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
82 | <citerefentry><refentrytitle>sd_event_add_post</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
42f1ab50 | 83 | and |
dc83f27a | 84 | <citerefentry><refentrytitle>sd_event_add_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>. |
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85 | </para> |
86 | ||
dc83f27a LP |
87 | <para>For low-level control of event loop execution, use |
88 | <citerefentry><refentrytitle>sd_event_prepare</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
89 | <citerefentry><refentrytitle>sd_event_wait</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
90 | and | |
91 | <citerefentry><refentrytitle>sd_event_dispatch</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
92 | which are wrapped by <function>sd_event_run()</function>. Along | |
93 | with | |
94 | <citerefentry><refentrytitle>sd_event_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
95 | these functions allow integration of an | |
96 | <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
97 | event loop into foreign event loop implementations.</para> | |
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98 | </refsect1> |
99 | ||
100 | <refsect1> | |
101 | <title>Return Value</title> | |
102 | ||
dc83f27a LP |
103 | <para>On failure, these functions return a negative errno-style |
104 | error code. <function>sd_event_run()</function> returns a | |
105 | positive, non-zero integer if an event source was dispatched, and | |
106 | zero when the specified timeout hit before an event source has | |
107 | seen any event, and hence no event source was | |
108 | dispatched. <function>sd_event_loop()</function> returns the exit | |
109 | code specified when invoking | |
110 | <function>sd_event_exit()</function>.</para> | |
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111 | </refsect1> |
112 | ||
113 | <refsect1> | |
114 | <title>Errors</title> | |
115 | ||
116 | <para>Returned errors may indicate the following problems:</para> | |
117 | ||
118 | <variablelist> | |
119 | <varlistentry> | |
120 | <term><constant>-EINVAL</constant></term> | |
121 | ||
a8eaaee7 | 122 | <listitem><para>The <parameter>event</parameter> parameter is |
dc83f27a | 123 | invalid or <constant>NULL</constant>.</para></listitem> |
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124 | </varlistentry> |
125 | ||
126 | <varlistentry> | |
127 | <term><constant>-EBUSY</constant></term> | |
128 | ||
129 | <listitem><para>The event loop object is not in the right | |
130 | state (see | |
131 | <citerefentry><refentrytitle>sd_event_prepare</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
132 | for an explanation of possible states).</para></listitem> | |
133 | </varlistentry> | |
134 | ||
135 | <varlistentry> | |
136 | <term><constant>-ESTALE</constant></term> | |
137 | ||
138 | <listitem><para>The event loop is already terminated.</para></listitem> | |
139 | ||
140 | </varlistentry> | |
141 | ||
142 | <varlistentry> | |
143 | <term><constant>-ECHILD</constant></term> | |
144 | ||
145 | <listitem><para>The event loop has been created in a different process.</para></listitem> | |
146 | ||
147 | </varlistentry> | |
148 | ||
149 | </variablelist> | |
150 | ||
b938cb90 | 151 | <para>Other errors are possible, too.</para> |
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152 | </refsect1> |
153 | ||
dc83f27a | 154 | <xi:include href="libsystemd-pkgconfig.xml" /> |
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155 | |
156 | <refsect1> | |
157 | <title>See Also</title> | |
158 | ||
159 | <para> | |
160 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
161 | <citerefentry><refentrytitle>sd_event_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
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162 | <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
163 | <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
164 | <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
165 | <citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
166 | <citerefentry><refentrytitle>sd_event_add_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
c268628a | 167 | <citerefentry><refentrytitle>sd_event_add_post</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
dc83f27a LP |
168 | <citerefentry><refentrytitle>sd_event_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
169 | <citerefentry><refentrytitle>sd_event_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
170 | <citerefentry><refentrytitle>sd_event_wait</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
a8eaaee7 | 171 | <ulink url="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html">GLib Main Event Loop</ulink>. |
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172 | </para> |
173 | </refsect1> | |
174 | ||
175 | </refentry> |