man: add sd_bus_message_new_signal(3)

This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2018-07-24 23:23:29 +02:00
parent 5b316330be
commit e8b84fcca6
4 changed files with 134 additions and 0 deletions

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@ -216,6 +216,7 @@ manpages = [
'sd_bus_message_new_method_errnof',
'sd_bus_message_new_method_errorf'],
''],
['sd_bus_message_new_signal', '3', [], ''],
['sd_bus_message_read', '3', ['sd_bus_message_readv'], ''],
['sd_bus_message_read_basic', '3', [], ''],
['sd_bus_message_set_destination', '3', ['sd_bus_message_set_sender'], ''],

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@ -61,6 +61,7 @@
<citerefentry><refentrytitle>sd_bus_message_get_cookie</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_message_get_monotonic_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_message_new_method_error</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_message_new_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_message_read_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_message_read</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_message_set_destination</refentrytitle><manvolnum>3</manvolnum></citerefentry>,

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@ -0,0 +1,116 @@
<?xml version='1.0'?>
<!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+ -->
<refentry id="sd_bus_message_new_signal"
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd_bus_message_new_signal</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>sd_bus_message_new_signal</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_bus_message_new_signal</refname>
<refpurpose>Create a signal message</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int sd_bus_message_new_signal</funcdef>
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
<paramdef>sd_bus_message **<parameter>m</parameter></paramdef>
<paramdef>const char *<parameter>path</parameter></paramdef>
<paramdef>const char *<parameter>interface</parameter></paramdef>
<paramdef>const char *<parameter>member</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>The <function>sd_bus_message_new_signal()</function> function creates a new bus message
object that encapsulates a D-Bus signal, and returns it in the <parameter>m</parameter> output
parameter. The signal will be sent to path <parameter>path</parameter>, on the interface
<parameter>interface</parameter>, member <parameter>member</parameter>. When this message is
sent, no reply is expected.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>This function returns 0 if the message object was successfully created, and a negative
errno-style error code otherwise.</para>
</refsect1>
<refsect1 id='errors'>
<title>Errors</title>
<para>Returned errors may indicate the following problems:</para>
<variablelist>
<varlistentry>
<term><constant>-EINVAL</constant></term>
<listitem><para>The output parameter <parameter>m</parameter> is
<constant>NULL</constant>.</para>
<para>The <parameter>path</parameter> parameter is not a valid D-Bus path
(<literal>/an/object/path</literal>), the <parameter>interface</parameter> parameter is not
a valid D-Bus interface name (<literal>an.interface.name</literal>), or the
<parameter>member</parameter> parameter is not a valid D-Bus member
(<literal>Name</literal>).</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>-ENOTCONN</constant></term>
<listitem><para>The bus parameter <parameter>bus</parameter> is <constant>NULL</constant> or
the bus is not connected.</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>-ENOMEM</constant></term>
<listitem><para>Memory allocation failed.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<xi:include href="libsystemd-pkgconfig.xml" />
<refsect1>
<title>Examples</title>
<example>
<title>Send a simple signal</title>
<programlisting><xi:include href="send-unit-files-changed.c" parse="text" /></programlisting>
<para>This function in systemd sources is used to emit the
<literal>UnitFilesChanged</literal> signal when the unit files have been changed.
</para>
</example>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>

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@ -0,0 +1,16 @@
#include <systemd/sd-bus.h>
#define _cleanup_(f) __attribute__((cleanup(f)))
int send_unit_files_changed(sd_bus *bus) {
_cleanup_(sd_bus_message_unrefp) sd_bus_message *message = NULL;
int r;
r = sd_bus_message_new_signal(bus, &message,
"/org/freedesktop/systemd1",
"org.freedesktop.systemd1.Manager",
"UnitFilesChanged");
if (r < 0)
return r;
return sd_bus_send(bus, message, NULL);
}