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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"

"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

<refentry id="sd_event_source_unref" xmlns:xi="http://www.w3.org/2001/XInclude">

<refentryinfo>

<title>sd_event_source_unref</title>

<productname>systemd</productname>

<authorgroup>

<author>

<contrib>Developer</contrib>

<firstname>Lennart</firstname>

<surname>Poettering</surname>

<email>lennart@poettering.net</email>

</author>

</authorgroup>

</refentryinfo>

<refmeta>

<refentrytitle>sd_event_source_unref</refentrytitle>

<manvolnum>3</manvolnum>

</refmeta>

<refnamediv>

<refname>sd_event_source_unref</refname>

<refname>sd_event_source_ref</refname>

<refpurpose>Increase or decrease event source reference counters</refpurpose>

</refnamediv>

<refsynopsisdiv>

<funcsynopsis>

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

<funcprototype>

<funcdef>sd_event_source* <function>sd_event_source_unref</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>

</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_ref()</function> may be used

to increase by one the reference counter of the event source object

specified as <parameter>source</parameter>.</para>

<para>Both functions 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>.</para>

</refsect1>

<refsect1>

<title>Return Value</title>

<para><function>sd_event_source_unref()</function> always returns

<constant>NULL</constant>.

<function>sd_event_source_ref()</function> always returns the

event source object passed in.</para>

</refsect1>

<xi:include href="libsystemd-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_child</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_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>

</para>

</refsect1>

</refentry>