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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">
-
-<!--
- SPDX-License-Identifier: LGPL-2.1+
--->
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
+ "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="sd_event_add_signal" xmlns:xi="http://www.w3.org/2001/XInclude">
project='man-pages'><refentrytitle>signalfd</refentrytitle><manvolnum>2</manvolnum></citerefentry>
for further information.</para>
- <para>Only a single handler may be installed for a specific
- signal. The signal will be unblocked by this call, and must be
- blocked before this function is called in all threads (using
+ <para>Only a single handler may be installed for a specific signal. The signal must be blocked in all
+ threads before this function is called (using <citerefentry
+ project='man-pages'><refentrytitle>sigprocmask</refentrytitle><manvolnum>2</manvolnum></citerefentry> or
<citerefentry
- project='man-pages'><refentrytitle>sigprocmask</refentrytitle><manvolnum>2</manvolnum></citerefentry>). If
- the handler is not specified (<parameter>handler</parameter> is
- <constant>NULL</constant>), a default handler which causes the
- program to exit cleanly will be used.</para>
+ project='man-pages'><refentrytitle>pthread_sigmask</refentrytitle><manvolnum>3</manvolnum></citerefentry>).</para>
<para>By default, the event source is enabled permanently
(<constant>SD_EVENT_ON</constant>), but this may be changed with
"floating", and will be destroyed implicitly when the event loop
itself is destroyed.</para>
+ <para>If the <parameter>handler</parameter> parameter to <function>sd_event_add_signal()</function> is
+ <constant>NULL</constant>, and the event source fires, this will be considered a request to exit the
+ event loop. In this case, the <parameter>userdata</parameter> parameter, cast to an integer, is passed as
+ the exit code parameter to
+ <citerefentry><refentrytitle>sd_event_exit</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
+
<para><function>sd_event_source_get_signal()</function> returns
the configured signal number of an event source created previously
with <function>sd_event_add_signal()</function>. It takes the
<para>On success, these functions return 0 or a positive
integer. On failure, they return a negative errno-style error
code.</para>
- </refsect1>
- <refsect1>
- <title>Errors</title>
+ <refsect2>
+ <title>Errors</title>
- <para>Returned errors may indicate the following problems:</para>
+ <para>Returned errors may indicate the following problems:</para>
- <variablelist>
- <varlistentry>
- <term><constant>-ENOMEM</constant></term>
+ <variablelist>
+ <varlistentry>
+ <term><constant>-ENOMEM</constant></term>
- <listitem><para>Not enough memory to allocate an object.</para></listitem>
- </varlistentry>
+ <listitem><para>Not enough memory to allocate an object.</para></listitem>
+ </varlistentry>
- <varlistentry>
- <term><constant>-EINVAL</constant></term>
+ <varlistentry>
+ <term><constant>-EINVAL</constant></term>
- <listitem><para>An invalid argument has been passed.</para></listitem>
- </varlistentry>
+ <listitem><para>An invalid argument has been passed.</para></listitem>
+ </varlistentry>
- <varlistentry>
- <term><constant>-EBUSY</constant></term>
+ <varlistentry>
+ <term><constant>-EBUSY</constant></term>
- <listitem><para>A handler is already installed for this
- signal or the signal was not blocked previously.</para></listitem>
- </varlistentry>
+ <listitem><para>A handler is already installed for this
+ signal or the signal was not blocked previously.</para></listitem>
+ </varlistentry>
- <varlistentry>
- <term><constant>-ESTALE</constant></term>
+ <varlistentry>
+ <term><constant>-ESTALE</constant></term>
- <listitem><para>The event loop is already terminated.</para></listitem>
- </varlistentry>
+ <listitem><para>The event loop is already terminated.</para></listitem>
+ </varlistentry>
- <varlistentry>
- <term><constant>-ECHILD</constant></term>
+ <varlistentry>
+ <term><constant>-ECHILD</constant></term>
- <listitem><para>The event loop has been created in a different process.</para></listitem>
- </varlistentry>
+ <listitem><para>The event loop has been created in a different process.</para></listitem>
+ </varlistentry>
- <varlistentry>
- <term><constant>-EDOM</constant></term>
+ <varlistentry>
+ <term><constant>-EDOM</constant></term>
- <listitem><para>The passed event source is not a signal event source.</para></listitem>
- </varlistentry>
+ <listitem><para>The passed event source is not a signal event source.</para></listitem>
+ </varlistentry>
- </variablelist>
+ </variablelist>
+ </refsect2>
</refsect1>
<xi:include href="libsystemd-pkgconfig.xml" />
<citerefentry><refentrytitle>sd_event_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_event_source_set_description</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_event_source_set_userdata</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_event_source_set_floating</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry project='man-pages'><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
- <citerefentry project='man-pages'><refentrytitle>signalfd</refentrytitle><manvolnum>2</manvolnum></citerefentry>
+ <citerefentry project='man-pages'><refentrytitle>signalfd</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>sigprocmask</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>pthread_sigmask</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>