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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 | <!-- | |
6 | This file is part of systemd. | |
7 | ||
8 | Copyright 2015 Zbigniew Jędrzejewski-Szmek | |
9 | ||
10 | systemd is free software; you can redistribute it and/or modify it | |
11 | under the terms of the GNU Lesser General Public License as published by | |
12 | the Free Software Foundation; either version 2.1 of the License, or | |
13 | (at your option) any later version. | |
14 | ||
15 | systemd is distributed in the hope that it will be useful, but | |
16 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
18 | Lesser General Public License for more details. | |
19 | ||
20 | You should have received a copy of the GNU Lesser General Public License | |
21 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
22 | --> | |
23 | ||
48f69d8f | 24 | <refentry id="sd_event_run"> |
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25 | |
26 | <refentryinfo> | |
27 | <title>sd_event_run</title> | |
28 | <productname>systemd</productname> | |
29 | ||
30 | <authorgroup> | |
31 | <author> | |
32 | <contrib>Developer</contrib> | |
33 | <firstname>Tom</firstname> | |
34 | <surname>Gundersen</surname> | |
35 | <email>teg@jklm.no</email> | |
36 | </author> | |
37 | </authorgroup> | |
38 | </refentryinfo> | |
39 | ||
40 | <refmeta> | |
41 | <refentrytitle>sd_event_run</refentrytitle> | |
42 | <manvolnum>3</manvolnum> | |
43 | </refmeta> | |
44 | ||
45 | <refnamediv> | |
46 | <refname>sd_event_run</refname> | |
47 | <refname>sd_event_loop</refname> | |
48 | ||
a8eaaee7 | 49 | <refpurpose>Run the libsystemd event loop</refpurpose> |
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50 | </refnamediv> |
51 | ||
52 | <refsynopsisdiv> | |
53 | <funcsynopsis> | |
54 | <funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo> | |
55 | ||
56 | <funcprototype> | |
57 | <funcdef>int <function>sd_event_run</function></funcdef> | |
58 | <paramdef>sd_event *<parameter>event</parameter></paramdef> | |
59 | <paramdef>uint64_t <parameter>timeout</parameter></paramdef> | |
60 | </funcprototype> | |
61 | ||
62 | <funcprototype> | |
63 | <funcdef>int <function>sd_event_loop</function></funcdef> | |
64 | <paramdef>sd_event *<parameter>event</parameter></paramdef> | |
65 | </funcprototype> | |
66 | </funcsynopsis> | |
67 | </refsynopsisdiv> | |
68 | ||
69 | <refsect1> | |
70 | <title>Description</title> | |
71 | ||
72 | <para><function>sd_event_run()</function> can be used to run one | |
73 | iteration of the event loop of libsystemd. This function waits | |
b938cb90 | 74 | until an event to process is available, and dispatches a handler |
a8eaaee7 | 75 | for it. The <parameter>timeout</parameter> parameter specifices the |
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76 | maximum time (in microseconds) to wait. <constant>(uint64_t) |
77 | -1</constant> may be used to specify an infinite timeout.</para> | |
78 | ||
79 | <para><function>sd_event_loop</function> runs | |
80 | <function>sd_event_wait</function> in a loop with a timeout of | |
81 | infinity. This makes it suitable for the main event loop of a | |
82 | program.</para> | |
83 | ||
84 | <para>The event loop object <parameter>event</parameter> is | |
85 | created with | |
86 | <function>sd_event_new</function>. | |
87 | Events to wait for and their handlers can be registered with | |
88 | <function>sd_event_add_time</function>, | |
89 | <function>sd_event_add_child</function>, | |
90 | <function>sd_event_add_signal</function>, | |
91 | <function>sd_event_add_defer</function>, | |
92 | <function>sd_event_add_exit</function>, | |
93 | and | |
94 | <function>sd_event_add_post</function>. | |
95 | </para> | |
96 | ||
97 | <para>For more fine-grained control, | |
98 | <function>sd_event_prepare</function>, | |
99 | <function>sd_event_wait</function>, and | |
100 | <function>sd_event_dispatch</function> may be used. Along with | |
101 | <function>sd_event_get_fd</function>, those functions make it | |
102 | possible to integrate the libsystemd loop inside of another event | |
103 | loop.</para> | |
104 | </refsect1> | |
105 | ||
106 | <refsect1> | |
107 | <title>Return Value</title> | |
108 | ||
109 | <para>On success, these functions return 0 or a positive integer. | |
110 | On failure, they return a negative errno-style error code. | |
111 | <function>sd_event_run</function> returns 0 if the event loop is | |
112 | finished, and a positive value if it can be continued.</para> | |
113 | </refsect1> | |
114 | ||
115 | <refsect1> | |
116 | <title>Errors</title> | |
117 | ||
118 | <para>Returned errors may indicate the following problems:</para> | |
119 | ||
120 | <variablelist> | |
121 | <varlistentry> | |
122 | <term><constant>-EINVAL</constant></term> | |
123 | ||
a8eaaee7 | 124 | <listitem><para>The <parameter>event</parameter> parameter is |
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125 | <constant>NULL</constant>.</para></listitem> |
126 | </varlistentry> | |
127 | ||
128 | <varlistentry> | |
129 | <term><constant>-EBUSY</constant></term> | |
130 | ||
131 | <listitem><para>The event loop object is not in the right | |
132 | state (see | |
133 | <citerefentry><refentrytitle>sd_event_prepare</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
134 | for an explanation of possible states).</para></listitem> | |
135 | </varlistentry> | |
136 | ||
137 | <varlistentry> | |
138 | <term><constant>-ESTALE</constant></term> | |
139 | ||
140 | <listitem><para>The event loop is already terminated.</para></listitem> | |
141 | ||
142 | </varlistentry> | |
143 | ||
144 | <varlistentry> | |
145 | <term><constant>-ECHILD</constant></term> | |
146 | ||
147 | <listitem><para>The event loop has been created in a different process.</para></listitem> | |
148 | ||
149 | </varlistentry> | |
150 | ||
151 | </variablelist> | |
152 | ||
b938cb90 | 153 | <para>Other errors are possible, too.</para> |
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154 | </refsect1> |
155 | ||
156 | <refsect1> | |
157 | <title>Notes</title> | |
158 | ||
159 | <para><function>sd_event_run()</function> and | |
160 | <function>sd_event_loop()</function> are available | |
161 | as a shared library, which can be compiled and linked to with the | |
162 | <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
163 | file.</para> | |
164 | </refsect1> | |
165 | ||
166 | <refsect1> | |
167 | <title>See Also</title> | |
168 | ||
169 | <para> | |
170 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
171 | <citerefentry><refentrytitle>sd_event_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
172 | <citerefentry><refentrytitle>sd_event_wait</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
173 | <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
174 | <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
175 | <citerefentry><refentrytitle>sd_event_add_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
176 | <citerefentry><refentrytitle>sd_event_add_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
177 | <citerefentry><refentrytitle>sd_event_add_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
c268628a | 178 | <citerefentry><refentrytitle>sd_event_add_post</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
a8eaaee7 | 179 | <ulink url="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html">GLib Main Event Loop</ulink>. |
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180 | </para> |
181 | </refsect1> | |
182 | ||
183 | </refentry> |