man/sd_event_exit.xml

   1 <?xml version='1.0'?>
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!-- SPDX-License-Identifier: LGPL-2.1+ -->
   5
   6 <refentry id="sd_event_exit" xmlns:xi="http://www.w3.org/2001/XInclude">
   7
   8   <refentryinfo>
   9     <title>sd_event_exit</title>
  10     <productname>systemd</productname>
  11   </refentryinfo>
  12
  13   <refmeta>
  14     <refentrytitle>sd_event_exit</refentrytitle>
  15     <manvolnum>3</manvolnum>
  16   </refmeta>
  17
  18   <refnamediv>
  19     <refname>sd_event_exit</refname>
  20     <refname>sd_event_get_exit_code</refname>
  21
  22     <refpurpose>Ask the event loop to exit</refpurpose>
  23   </refnamediv>
  24
  25   <refsynopsisdiv>
  26     <funcsynopsis>
  27       <funcsynopsisinfo>#include &lt;systemd/sd-event.h&gt;</funcsynopsisinfo>
  28
  29       <funcprototype>
  30         <funcdef>int <function>sd_event_exit</function></funcdef>
  31         <paramdef>sd_event *<parameter>event</parameter></paramdef>
  32         <paramdef>int <parameter>code</parameter></paramdef>
  33       </funcprototype>
  34
  35       <funcprototype>
  36         <funcdef>int <function>sd_event_get_exit_code</function></funcdef>
  37         <paramdef>sd_event *<parameter>event</parameter></paramdef>
  38         <paramdef>int *<parameter>code</parameter></paramdef>
  39       </funcprototype>
  40
  41     </funcsynopsis>
  42   </refsynopsisdiv>
  43
  44   <refsect1>
  45     <title>Description</title>
  46
  47     <para><function>sd_event_exit()</function> requests the event loop
  48     specified in the <parameter>event</parameter> event loop object to
  49     exit. The <parameter>code</parameter> parameter may be any integer
  50     value and is returned as-is by
  51     <citerefentry><refentrytitle>sd_event_loop</refentrytitle><manvolnum>3</manvolnum></citerefentry>
  52     after the last event loop iteration. It may also be queried
  53     using <function>sd_event_get_exit_code()</function>, see
  54     below. </para>
  55
  56     <para>When exiting is requested the event loop will stop listening
  57     for and dispatching regular event sources. Instead it will proceed
  58     with executing only event sources registered with
  59     <citerefentry><refentrytitle>sd_event_add_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>
  60     in the order defined by their priority. After all exit event
  61     sources have been dispatched the event loop is terminated.</para>
  62
  63     <para>If <function>sd_event_exit()</function> is invoked a second
  64     time while the event loop is still processing exit event sources,
  65     the exit code stored in the event loop object is updated, but
  66     otherwise no further operation is executed.</para>
  67
  68     <para><function>sd_event_get_exit_code()</function> may be used to
  69     query the exit code passed into
  70     <function>sd_event_exit()</function> earlier.</para>
  71
  72     <para>While the full positive and negative integer ranges may be used
  73     for the exit code, care should be taken not pick exit codes that
  74     conflict with regular exit codes returned by
  75     <function>sd_event_loop()</function>, if these exit codes shall be
  76     distinguishable.</para>
  77   </refsect1>
  78
  79   <refsect1>
  80     <title>Return Value</title>
  81
  82     <para>On success, <function>sd_event_exit()</function> and <function>sd_event_get_exit_code()</function>
  83     return 0 or a positive integer. On failure, they return a negative errno-style error code.</para>
  84
  85     <refsect2>
  86       <title>Errors</title>
  87
  88       <para>Returned errors may indicate the following problems:</para>
  89
  90       <variablelist>
  91
  92         <varlistentry>
  93           <term><constant>-EINVAL</constant></term>
  94
  95           <listitem><para>The event loop object or error code pointer are invalid.</para></listitem>
  96
  97         </varlistentry>
  98
  99         <varlistentry>
 100           <term><constant>-ECHILD</constant></term>
 101
 102           <listitem><para>The event loop was created in a different process.</para></listitem>
 103         </varlistentry>
 104
 105         <varlistentry>
 106           <term><constant>-ESTALE</constant></term>
 107
 108           <listitem><para>The event loop has exited already and all exit handlers are already processed.
 109           </para></listitem>
 110         </varlistentry>
 111
 112         <varlistentry>
 113           <term><constant>-ENODATA</constant></term>
 114
 115           <listitem><para>The event loop has not been requested to exit yet.</para></listitem>
 116         </varlistentry>
 117
 118       </variablelist>
 119     </refsect2>
 120   </refsect1>
 121
 122   <xi:include href="libsystemd-pkgconfig.xml" />
 123
 124   <refsect1>
 125     <title>See Also</title>
 126
 127     <para>
 128       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 129       <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 130       <citerefentry><refentrytitle>sd_event_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 131       <citerefentry><refentrytitle>sd_event_add_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 132     </para>
 133   </refsect1>
 134
 135 </refentry>