<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> <!-- This file is part of systemd. Copyright 2015 Zbigniew Jędrzejewski-Szmek systemd is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. --> <refentry id="sd_event_run"> <refentryinfo> <title>sd_event_run</title> <productname>systemd</productname> <authorgroup> <author> <contrib>Developer</contrib> <firstname>Tom</firstname> <surname>Gundersen</surname> <email>teg@jklm.no</email> </author> </authorgroup> </refentryinfo> <refmeta> <refentrytitle>sd_event_run</refentrytitle> <manvolnum>3</manvolnum> </refmeta> <refnamediv> <refname>sd_event_run</refname> <refname>sd_event_loop</refname> <refpurpose>Run libsystemd event loop</refpurpose> </refnamediv> <refsynopsisdiv> <funcsynopsis> <funcsynopsisinfo>#include <systemd/sd-event.h></funcsynopsisinfo> <funcprototype> <funcdef>int <function>sd_event_run</function></funcdef> <paramdef>sd_event *<parameter>event</parameter></paramdef> <paramdef>uint64_t <parameter>timeout</parameter></paramdef> </funcprototype> <funcprototype> <funcdef>int <function>sd_event_loop</function></funcdef> <paramdef>sd_event *<parameter>event</parameter></paramdef> </funcprototype> </funcsynopsis> </refsynopsisdiv> <refsect1> <title>Description</title> <para><function>sd_event_run()</function> can be used to run one iteration of the event loop of libsystemd. This function waits until an event to process is available and dispatches a handler for it. Parameter <parameter>timeout</parameter> specifices the maximum time (in microseconds) to wait. <constant>(uint64_t) -1</constant> may be used to specify an infinite timeout.</para> <para><function>sd_event_loop</function> runs <function>sd_event_wait</function> in a loop with a timeout of infinity. This makes it suitable for the main event loop of a program.</para> <para>The event loop object <parameter>event</parameter> is created with <function>sd_event_new</function>. Events to wait for and their handlers can be registered with <function>sd_event_add_time</function>, <function>sd_event_add_child</function>, <function>sd_event_add_signal</function>, <function>sd_event_add_defer</function>, <function>sd_event_add_exit</function>, and <function>sd_event_add_post</function>. </para> <para>For more fine-grained control, <function>sd_event_prepare</function>, <function>sd_event_wait</function>, and <function>sd_event_dispatch</function> may be used. Along with <function>sd_event_get_fd</function>, those functions make it possible to integrate the libsystemd loop inside of another event loop.</para> </refsect1> <refsect1> <title>Return Value</title> <para>On success, these functions return 0 or a positive integer. On failure, they return a negative errno-style error code. <function>sd_event_run</function> returns 0 if the event loop is finished, and a positive value if it can be continued.</para> </refsect1> <refsect1> <title>Errors</title> <para>Returned errors may indicate the following problems:</para> <variablelist> <varlistentry> <term><constant>-EINVAL</constant></term> <listitem><para>Parameter <parameter>event</parameter> is <constant>NULL</constant>.</para></listitem> </varlistentry> <varlistentry> <term><constant>-EBUSY</constant></term> <listitem><para>The event loop object is not in the right state (see <citerefentry><refentrytitle>sd_event_prepare</refentrytitle><manvolnum>3</manvolnum></citerefentry> for an explanation of possible states).</para></listitem> </varlistentry> <varlistentry> <term><constant>-ESTALE</constant></term> <listitem><para>The event loop is already terminated.</para></listitem> </varlistentry> <varlistentry> <term><constant>-ECHILD</constant></term> <listitem><para>The event loop has been created in a different process.</para></listitem> </varlistentry> </variablelist> <para>Other errors are possible too.</para> </refsect1> <refsect1> <title>Notes</title> <para><function>sd_event_run()</function> and <function>sd_event_loop()</function> are available as a shared library, which can be compiled and linked to with the <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> file.</para> </refsect1> <refsect1> <title>See Also</title> <para> <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry><refentrytitle>sd_event_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>, <citerefentry><refentrytitle>sd_event_wait</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_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>, <citerefentry><refentrytitle>sd_event_add_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>, <citerefentry><refentrytitle>sd_event_add_post</refentrytitle><manvolnum>3</manvolnum></citerefentry>, <ulink url="https://developer.gnome.org/glib/unstable/glib-The-Main-Event-Loop.html">GLIb Main Event Loop</ulink>. </para> </refsect1> </refentry>