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systemd/man/sd_event_source_unref.xml
Zbigniew Jędrzejewski-Szmek 11a1589223 tree-wide: drop license boilerplate
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.

I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
2018-04-06 18:58:55 +02:00

132 lines
5.0 KiB
XML

<?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">
<!--
SPDX-License-Identifier: LGPL-2.1+
This file is part of systemd.
Copyright 2015 Lennart Poettering
-->
<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_unrefp</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>void <function>sd_event_source_unrefp</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_unrefp()</function> is similar to
<function>sd_event_source_unref()</function> but takes a pointer to a
pointer to an <type>sd_event_source</type> object. This call is useful in
conjunction with GCC's and LLVM's <ulink
url="https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html">Clean-up
Variable Attribute</ulink>. Note that this function is defined as
inline function.</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><function>sd_event_source_unref()</function>,
<function>sd_bus_creds_unrefp()</function> and
<function>sd_bus_creds_ref()</function> 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>