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<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 &lt;systemd/sd-event.h&gt;</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>