mirror of
https://github.com/systemd/systemd.git
synced 2024-11-23 18:23:32 +08:00
140 lines
5.3 KiB
XML
140 lines
5.3 KiB
XML
<?xml version='1.0'?>
|
|
<!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_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>
|
|
<refname>sd_bus_message_new_signal_to</refname>
|
|
|
|
<refpurpose>Create a signal message</refpurpose>
|
|
</refnamediv>
|
|
|
|
<refsynopsisdiv>
|
|
<funcsynopsis>
|
|
<funcsynopsisinfo>#include <systemd/sd-bus.h></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>
|
|
|
|
<funcprototype>
|
|
<funcdef>int sd_bus_message_new_signal_to</funcdef>
|
|
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
|
|
<paramdef>sd_bus_message **<parameter>m</parameter></paramdef>
|
|
<paramdef>const char *<parameter>destination</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. See
|
|
<citerefentry><refentrytitle>sd_bus_message_new_method_call</refentrytitle><manvolnum>1</manvolnum></citerefentry>
|
|
for a short description of the meaning of the <parameter>path</parameter>,
|
|
<parameter>interface</parameter>, and <parameter>member</parameter> parameters.
|
|
</para>
|
|
|
|
<para><function>sd_bus_message_new_signal_to()</function> is a shorthand for creating a new bus message
|
|
to a specific destination. It's behavior is similar to calling
|
|
<function>sd_bus_message_new_signal()</function> followed by calling
|
|
<citerefentry><refentrytitle>sd_bus_message_set_destination</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
|
|
</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>
|
|
|
|
<refsect2>
|
|
<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>
|
|
</refsect2>
|
|
</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>,
|
|
<citerefentry><refentrytitle>sd_bus_emit_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
|
<citerefentry><refentrytitle>sd_bus_message_set_destination</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
|
</para>
|
|
</refsect1>
|
|
|
|
</refentry>
|