2018-07-03 00:15:39 +03:00
<?xml version='1.0'?>
2019-03-14 16:40:58 +03:00
< !DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
2023-12-25 17:48:33 +03:00
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
2020-11-09 07:23:58 +03:00
<!-- SPDX - License - Identifier: LGPL - 2.1 - or - later -->
2015-11-20 01:38:54 +03:00
<refentry id= "sd_event_source_get_pending" xmlns:xi= "http://www.w3.org/2001/XInclude" >
<refentryinfo >
<title > sd_event_source_get_pending</title>
<productname > systemd</productname>
</refentryinfo>
<refmeta >
<refentrytitle > sd_event_source_get_pending</refentrytitle>
<manvolnum > 3</manvolnum>
</refmeta>
<refnamediv >
<refname > sd_event_source_get_pending</refname>
<refpurpose > Determine pending state of event sources</refpurpose>
</refnamediv>
<refsynopsisdiv >
<funcsynopsis >
<funcsynopsisinfo > #include < systemd/sd-event.h> </funcsynopsisinfo>
<funcprototype >
<funcdef > int <function > sd_event_source_get_pending</function> </funcdef>
<paramdef > sd_event_source *<parameter > source</parameter> </paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 >
<title > Description</title>
<para > <function > sd_event_source_get_pending()</function> may be
used to determine whether the event source object specified as
<parameter > source</parameter> has seen events but has not been
dispatched yet (and thus is marked "pending").</para>
<para > Event source objects initially are not marked pending, when
they are created with calls such as
<citerefentry > <refentrytitle > sd_event_add_io</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> ,
<citerefentry > <refentrytitle > sd_event_add_time</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> ,
with the exception of those created with
<citerefentry > <refentrytitle > sd_event_add_defer</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry>
which are immediately marked pending, and
<citerefentry > <refentrytitle > sd_event_add_exit</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry>
for which the "pending" concept is not defined. For details see
the respective manual pages.</para>
<para > In each event loop iteration one event source of those
marked pending is dispatched, in the order defined by the event
source priority, as set with
<citerefentry > <refentrytitle > sd_event_source_set_priority</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> .</para>
<para > For I/O event sources, as created with
<citerefentry > <refentrytitle > sd_event_add_io</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> ,
the call
2016-01-26 03:05:47 +03:00
<citerefentry > <refentrytitle > sd_event_source_get_io_revents</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry>
2015-11-20 01:38:54 +03:00
may be used to query the type of event pending in more
detail.</para>
</refsect1>
<refsect1 >
<title > Return Value</title>
2019-03-21 16:53:00 +03:00
<para > On success, <function > sd_event_source_get_pending()</function> returns an integer greater than zero
when the event source is marked pending, and zero when the event source is not marked pending. On
failure, it returns a negative errno-style error code.</para>
2015-11-20 01:38:54 +03:00
2019-03-21 16:53:00 +03:00
<refsect2 >
<title > Errors</title>
2015-11-20 01:38:54 +03:00
2019-03-21 16:53:00 +03:00
<para > Returned errors may indicate the following problems:</para>
2015-11-20 01:38:54 +03:00
2019-03-21 16:53:00 +03:00
<variablelist >
<varlistentry >
<term > <constant > -EINVAL</constant> </term>
2015-11-20 01:38:54 +03:00
2019-03-21 16:53:00 +03:00
<listitem > <para > <parameter > source</parameter> is not a valid pointer to an
<structname > sd_event_source</structname> object.</para> </listitem>
</varlistentry>
2015-11-20 01:38:54 +03:00
2019-03-21 16:53:00 +03:00
<varlistentry >
<term > <constant > -EDOM</constant> </term>
2015-11-20 01:38:54 +03:00
2019-03-21 16:53:00 +03:00
<listitem > <para > <parameter > source</parameter> refers to an event source object created with
<citerefentry > <refentrytitle > sd_event_add_exit</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> .</para> </listitem>
</varlistentry>
2015-11-20 01:38:54 +03:00
2019-03-21 16:53:00 +03:00
<varlistentry >
<term > <constant > -ENOMEM</constant> </term>
2015-11-20 01:38:54 +03:00
2019-03-21 16:53:00 +03:00
<listitem > <para > Not enough memory.</para> </listitem>
</varlistentry>
2015-11-20 01:38:54 +03:00
2019-03-21 16:53:00 +03:00
<varlistentry >
<term > <constant > -ESTALE</constant> </term>
2015-11-20 01:38:54 +03:00
2019-03-21 16:53:00 +03:00
<listitem > <para > The event loop is already terminated.</para> </listitem>
2015-11-20 01:38:54 +03:00
2019-03-21 16:53:00 +03:00
</varlistentry>
2015-11-20 01:38:54 +03:00
2019-03-21 16:53:00 +03:00
<varlistentry >
<term > <constant > -ECHILD</constant> </term>
2015-11-20 01:38:54 +03:00
2023-04-25 03:46:22 +03:00
<listitem > <para > The event loop has been created in a different process, library or module instance.</para> </listitem>
2015-11-20 01:38:54 +03:00
2019-03-21 16:53:00 +03:00
</varlistentry>
2015-11-20 01:38:54 +03:00
2019-03-21 16:53:00 +03:00
</variablelist>
</refsect2>
2015-11-20 01:38:54 +03:00
</refsect1>
<xi:include href= "libsystemd-pkgconfig.xml" />
2023-09-04 15:46:35 +03:00
<refsect1 >
<title > History</title>
<para > <function > sd_event_source_get_pending()</function> was added in version 229.</para>
</refsect1>
2015-11-20 01:38:54 +03:00
<refsect1 >
<title > See Also</title>
2023-12-22 21:09:32 +03:00
<para > <simplelist type= "inline" >
<member > <citerefentry > <refentrytitle > sd-event</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> </member>
<member > <citerefentry > <refentrytitle > sd_event_add_io</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> </member>
<member > <citerefentry > <refentrytitle > sd_event_add_time</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> </member>
<member > <citerefentry > <refentrytitle > sd_event_add_signal</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> </member>
<member > <citerefentry > <refentrytitle > sd_event_add_child</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> </member>
<member > <citerefentry > <refentrytitle > sd_event_add_inotify</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> </member>
<member > <citerefentry > <refentrytitle > sd_event_add_defer</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> </member>
<member > <citerefentry > <refentrytitle > sd_event_source_unref</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> </member>
</simplelist> </para>
2015-11-20 01:38:54 +03:00
</refsect1>
</refentry>