mirror of
https://github.com/systemd/systemd.git
synced 2024-12-26 03:22:00 +03:00
3802a3d3d7
In the long run we really should figure out if we want to stick with 8ch or 2ch indenting, and not continue with half-and-half. For now, just make emacs aware of the files that use 2ch indenting.
199 lines
7.3 KiB
XML
199 lines
7.3 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">
|
||
|
||
<!--
|
||
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.
|
||
|
||
systemd is distributed in the hope that it will be useful, but
|
||
WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||
Lesser General Public License for more details.
|
||
|
||
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><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><refentrytitle>signalfd</refentrytitle><manvolnum>2</manvolnum></citerefentry>
|
||
for futher 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>
|