+++ /dev/null
-<?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">
-
-<!--
- This file is part of systemd.
-
- Copyright 2014 Zbigniew Jędrzejewski-Szmek
-
- systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 2.1 of the License, or
- (at your option) any later version.
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- WITHOUT ANY WARRANTY; without even the implied warranty of
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- Lesser General Public License for more details.
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- You should have received a copy of the GNU Lesser General Public License
- along with systemd; If not, see <http://www.gnu.org/licenses/>.
--->
-
-<refentry id="sd_event_add_signal" conditional="ENABLE_KDBUS">
-
- <refentryinfo>
- <title>sd_event_add_signal</title>
- <productname>systemd</productname>
-
- <authorgroup>
- <author>
- <contrib>More text</contrib>
- <firstname>Zbigniew</firstname>
- <surname>Jędrzejewski-Szmek</surname>
- <email>zbyszek@in.waw.pl</email>
- </author>
- </authorgroup>
- </refentryinfo>
-
- <refmeta>
- <refentrytitle>sd_event_add_signal</refentrytitle>
- <manvolnum>3</manvolnum>
- </refmeta>
-
- <refnamediv>
- <refname>sd_event_add_signal</refname>
- <refname>sd_event_source_get_signal</refname>
-
- <refpurpose>Add a signal event source to an event loop</refpurpose>
- </refnamediv>
-
- <refsynopsisdiv>
- <funcsynopsis>
- <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
-
- <funcprototype>
- <funcdef>int <function>sd_event_add_signal</function></funcdef>
- <paramdef>sd_event *<parameter>event</parameter></paramdef>
- <paramdef>sd_event_source **<parameter>source</parameter></paramdef>
- <paramdef>int <parameter>signal</parameter></paramdef>
- <paramdef>sd_event_signal_handler_t <parameter>handler</parameter></paramdef>
- <paramdef>void *<parameter>userdata</parameter></paramdef>
- </funcprototype>
-
- <funcprototype>
- <funcdef>typedef int (*<function>sd_event_signal_handler_t</function>)</funcdef>
- <paramdef>sd_event_source *<parameter>s</parameter></paramdef>
- <paramdef>const struct signalfd_siginfo *<parameter>si</parameter></paramdef>
- <paramdef>void *<parameter>userdata</parameter></paramdef>
- </funcprototype>
-
- <funcprototype>
- <funcdef>int <function>sd_event_source_get_signal</function></funcdef>
- <paramdef>sd_event_source *<parameter>source</parameter></paramdef>
- </funcprototype>
-
- </funcsynopsis>
- </refsynopsisdiv>
-
- <refsect1>
- <title>Description</title>
-
- <para><function>sd_event_add_signal()</function> adds a new signal
- event source to an event loop object. The event loop is specified
- in <parameter>event</parameter>, the event source is returned in
- the <parameter>source</parameter> parameter. The
- <parameter>signal</parameter> parameter specifies the signal to be handled
- (see
- <citerefentry project='man-pages'><refentrytitle>signal</refentrytitle><manvolnum>7</manvolnum></citerefentry>).
- The <parameter>handler</parameter> must reference a function to
- call when the signal is delivered or be <constant>NULL</constant>.
- The handler function will be passed the
- <parameter>userdata</parameter> pointer, which may be chosen
- freely by the caller. The handler also receives a pointer to a
- <structname>const struct signalfd_siginfo</structname> containing
- the information about the received signal. See
- <citerefentry 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, and must be
- blocked when the function is called. If the handler is not
- specified (<parameter>handler</parameter> is
- <constant>NULL</constant>), a default handler which causes the
- program to exit will be used. By default, the handler is enabled
- permanently (<constant>SD_EVENT_ON</constant>), but this may be
- changed with
- <citerefentry><refentrytitle>sd_event_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
- If the handler function returns a negative error code, it will be
- disabled after the invocation, even if
- <constant>SD_EVENT_ON</constant> mode is set.
- </para>
-
- <para><function>sd_event_source_get_signal()</function> retrieves
- the configured signal number of a signal event source created
- previously with <function>sd_event_add_signal()</function>. It
- takes the event source object as the <parameter>source</parameter>
- parameter.</para>
-
- </refsect1>
-
- <refsect1>
- <title>Return Value</title>
-
- <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>
-
- <para>Returned errors may indicate the following problems:</para>
-
- <variablelist>
- <varlistentry>
- <term><constant>-ENOMEM</constant></term>
-
- <listitem><para>Not enough memory to allocate an object.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><constant>-EINVAL</constant></term>
-
- <listitem><para>An invalid argument has been passed.</para></listitem>
-
- </varlistentry>
-
- <varlistentry>
- <term><constant>-EBUSY</constant></term>
-
- <listitem><para>An handler is already installed for this
- signal or the signal was not blocked previously.</para></listitem>
-
- </varlistentry>
-
- <varlistentry>
- <term><constant>-ESTALE</constant></term>
-
- <listitem><para>The event loop is already terminated.</para></listitem>
-
- </varlistentry>
-
- <varlistentry>
- <term><constant>-ECHILD</constant></term>
-
- <listitem><para>The event loop has been created in a different process.</para></listitem>
-
- </varlistentry>
-
- </variablelist>
- </refsect1>
-
- <refsect1>
- <title>Notes</title>
-
- <para><function>sd_event_add_signal()</function> and the other functions
- described here are available as a shared library, which can be
- compiled and linked to with the
- <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
- file.</para>
- </refsect1>
-
- <refsect1>
- <title>See Also</title>
-
- <para>
- <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd-event</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd_event_new</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_defer</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd_event_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- </para>
- </refsect1>
-
-</refentry>
~ianmdlvl / elogind.git / blobdiff