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mirror of https://github.com/systemd/systemd-stable.git synced 2024-12-22 13:33:56 +03:00

man: add sd_event_add_signal(3)

This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2014-09-25 17:27:27 -04:00
parent 3a17521f59
commit 3144ebcad3
3 changed files with 221 additions and 6 deletions

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@ -741,6 +741,7 @@ MANPAGES += \
man/sd_bus_open_user.3 \
man/sd_bus_path_encode.3 \
man/sd_bus_request_name.3 \
man/sd_event_add_signal.3 \
man/sd_event_add_time.3 \
man/sd_event_new.3 \
man/systemd-bus-proxyd.8 \
@ -802,6 +803,7 @@ MANPAGES_ALIAS += \
man/sd_bus_unref.3 \
man/sd_event_default.3 \
man/sd_event_ref.3 \
man/sd_event_source_get_signal.3 \
man/sd_event_source_get_time.3 \
man/sd_event_source_get_time_accuracy.3 \
man/sd_event_source_get_time_clock.3 \
@ -865,6 +867,7 @@ man/sd_bus_release_name.3: man/sd_bus_request_name.3
man/sd_bus_unref.3: man/sd_bus_new.3
man/sd_event_default.3: man/sd_event_new.3
man/sd_event_ref.3: man/sd_event_new.3
man/sd_event_source_get_signal.3: man/sd_event_add_signal.3
man/sd_event_source_get_time.3: man/sd_event_add_time.3
man/sd_event_source_get_time_accuracy.3: man/sd_event_add_time.3
man/sd_event_source_get_time_clock.3: man/sd_event_add_time.3
@ -1040,6 +1043,9 @@ man/sd_event_default.html: man/sd_event_new.html
man/sd_event_ref.html: man/sd_event_new.html
$(html-alias)
man/sd_event_source_get_signal.html: man/sd_event_add_signal.html
$(html-alias)
man/sd_event_source_get_time.html: man/sd_event_add_time.html
$(html-alias)
@ -1542,6 +1548,7 @@ EXTRA_DIST += \
man/sd_bus_open_user.xml \
man/sd_bus_path_encode.xml \
man/sd_bus_request_name.xml \
man/sd_event_add_signal.xml \
man/sd_event_add_time.xml \
man/sd_event_new.xml \
man/sd_get_seats.xml \

196
man/sd_event_add_signal.xml Normal file
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@ -0,0 +1,196 @@
<?xml version='1.0'?> <!--*-nxml-*-->
<!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 &lt;systemd/sd-bus.h&gt;</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><varname>-ENOMEM</varname></term>
<listitem><para>Not enough memory to allocate an object.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>-EINVAL</varname></term>
<listitem><para>An invalid argument has been passed.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>-EBUSY</varname></term>
<listitem><para>An handler is already installed for this
signal or the signal was not blocked previously.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>-ESTALE</varname></term>
<listitem><para>The event loop is already terminated.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>-ECHILD</varname></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_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>

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@ -68,6 +68,13 @@ along with systemd; If not, see <http://www.gnu.org/licenses/>.
<paramdef>void *<parameter>userdata</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>typedef int (*<function>sd_event_time_handler_t</function>)</funcdef>
<paramdef>sd_event_source *<parameter>s</parameter></paramdef>
<paramdef>uint64_t <parameter>usec</parameter></paramdef>
<paramdef>void *<parameter>userdata</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_event_source_get_time</function></funcdef>
<paramdef>sd_event_source *<parameter>source</parameter></paramdef>
@ -132,11 +139,15 @@ along with systemd; If not, see <http://www.gnu.org/licenses/>.
actually have been called at a slightly later time, subject to the
specified accuracy value, the kernel timer slack (see
<citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>)
and additional scheduling latencies. By default, the timer will
elapse once (SD_EVENT_ONESHOT), 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 SD_EVENT_ON mode is set.
and additional scheduling latencies.</para>
<para>By default, the timer will elapse once
(<constant>SD_EVENT_ONESHOT</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_time()</function> retrieves
@ -187,7 +198,7 @@ along with systemd; If not, see <http://www.gnu.org/licenses/>.
<varlistentry>
<term><varname>-ENOMEM</varname></term>
<listitem><para>Not enough memory to allocate object.</para></listitem>
<listitem><para>Not enough memory to allocate an object.</para></listitem>
</varlistentry>
<varlistentry>
@ -237,6 +248,7 @@ along with systemd; If not, see <http://www.gnu.org/licenses/>.
<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_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>clock_gettime</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_event_source_set_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>