-<?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">
+<?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">
<!--
- This file is part of systemd.
+ SPDX-License-Identifier: LGPL-2.1+
- Copyright 2016 Julian Orth
-
- 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/>.
+ Copyright © 2016 Julian Orth
-->
-<refentry id="sd_bus_add_match">
+<refentry id="sd_bus_add_match" xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd_bus_add_match</title>
<productname>systemd</productname>
-
- <authorgroup>
- <author>
- <firstname>Julian</firstname>
- <surname>Orth</surname>
- <email>ju.orth@gmail.com</email>
- </author>
- </authorgroup>
</refentryinfo>
<refmeta>
<refnamediv>
<refname>sd_bus_add_match</refname>
+ <refname>sd_bus_add_match_async</refname>
+ <refname>sd_bus_match_signal</refname>
+ <refname>sd_bus_match_signal_async</refname>
- <refpurpose>Add a match rule for message dispatching</refpurpose>
+ <refpurpose>Add a match rule for incoming message dispatching</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
+ <funcprototype>
+ <funcdef>typedef int (*<function>sd_bus_message_handler_t</function>)</funcdef>
+ <paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
+ <paramdef>void *<parameter>userdata</parameter></paramdef>
+ <paramdef>sd_bus_error *<parameter>ret_error</parameter></paramdef>
+ </funcprototype>
+
<funcprototype>
<funcdef>int <function>sd_bus_add_match</function></funcdef>
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
</funcprototype>
<funcprototype>
- <funcdef>typedef int (*<function>sd_bus_message_handler_t</function>)</funcdef>
- <paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
+ <funcdef>int <function>sd_bus_add_match_async</function></funcdef>
+ <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
+ <paramdef>sd_bus_slot **<parameter>slot</parameter></paramdef>
+ <paramdef>const char *<parameter>match</parameter></paramdef>
+ <paramdef>sd_bus_message_handler_t <parameter>callback</parameter></paramdef>
+ <paramdef>sd_bus_message_handler_t <parameter>install_callback</parameter></paramdef>
<paramdef>void *<parameter>userdata</parameter></paramdef>
- <paramdef>sd_bus_error *<parameter>ret_error</parameter></paramdef>
</funcprototype>
+
+ <funcprototype>
+ <funcdef>int <function>sd_bus_match_signal</function></funcdef>
+ <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
+ <paramdef>sd_bus_slot **<parameter>slot</parameter></paramdef>
+ <paramdef>const char *<parameter>sender</parameter></paramdef>
+ <paramdef>const char *<parameter>path</parameter></paramdef>
+ <paramdef>const char *<parameter>interface</parameter></paramdef>
+ <paramdef>const char *<parameter>member</parameter></paramdef>
+ <paramdef>sd_bus_message_handler_t <parameter>callback</parameter></paramdef>
+ <paramdef>void *<parameter>userdata</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>int <function>sd_bus_match_signal_async</function></funcdef>
+ <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
+ <paramdef>sd_bus_slot **<parameter>slot</parameter></paramdef>
+ <paramdef>const char *<parameter>sender</parameter></paramdef>
+ <paramdef>const char *<parameter>path</parameter></paramdef>
+ <paramdef>const char *<parameter>interface</parameter></paramdef>
+ <paramdef>const char *<parameter>member</parameter></paramdef>
+ <paramdef>sd_bus_message_handler_t <parameter>callback</parameter></paramdef>
+ <paramdef>sd_bus_message_handler_t <parameter>install_callback</parameter></paramdef>
+ <paramdef>void *<parameter>userdata</parameter></paramdef>
+ </funcprototype>
+
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
- <para>
- <function>sd_bus_add_match()</function> adds a match rule used to dispatch
- incoming messages. The syntax of the rule passed in
- <parameter>match</parameter> is described in the
- <ulink url="https://dbus.freedesktop.org/doc/dbus-specification.html">D-Bus Specification</ulink>.
+ <para><function>sd_bus_add_match()</function> installs a match rule for messages received on the specified bus
+ connection object <parameter>bus</parameter>. The syntax of the match rule expression passed in
+ <parameter>match</parameter> is described in the <ulink
+ url="https://dbus.freedesktop.org/doc/dbus-specification.html">D-Bus Specification</ulink>. The specified handler
+ function <parameter>callback</parameter> is called for eaching incoming message matching the specified expression,
+ the <parameter>userdata</parameter> parameter is passed as-is to the callback function. The match is installed
+ synchronously when connected to a bus broker, i.e. the call sends a control message requested the match to be added
+ to the broker and waits until the broker confirms the match has been installed successfully.</para>
+
+ <para><function>sd_bus_add_match_async()</function> operates very similar to
+ <function>sd_bus_match_signal()</function>, however it installs the match asynchronously, in a non-blocking
+ fashion: a request is sent to the broker, but the call does not wait for a response. The
+ <parameter>install_callback</parameter> function is called when the response is later received, with the response
+ message from the broker as parameter. If this function is specified as <constant>NULL</constant> a default
+ implementation is used that terminates the bus connection should installing the match fail.</para>
+
+ <para><function>sd_bus_match_signal()</function> is very similar to <function>sd_bus_add_match()</function>, but
+ only matches signals, and instead of a match expression accepts four parameters: <parameter>sender</parameter> (the
+ service name of the sender), <parameter>path</parameter> (the object path of the emitting object),
+ <parameter>interface</parameter> (the interface the signal belongs to), <parameter>member</parameter> (the signal
+ name), from which the match string is internally generated. Optionally, these parameters may be specified as
+ <constant>NULL</constant> in which case the relevant field of incoming signals is not tested.</para>
+
+ <para><function>sd_bus_match_signal_async()</function> combines the signal matching logic of
+ <function>sd_bus_match_signal()</function> with the asynchronous behaviour of
+ <function>sd_bus_add_match_async()</function>.</para>
+
+ <para>On success, and if non-<constant>NULL</constant>, the <parameter>slot</parameter> return parameter will be
+ set to a slot object that may be used as a reference to the installed match, and may be utilized to remove it again
+ at a later time with
+ <citerefentry><refentrytitle>sd_bus_slot_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>. If specified
+ as <constant>NULL</constant> the lifetime of the match is bound to the lifetime of the bus object itself, and the
+ match is generally not removed independently. See
+ <citerefentry><refentrytitle>sd_bus_slot_set_floating</refentrytitle><manvolnum>3</manvolnum></citerefentry> for
+ details.</para>
+
+ <para>The message <parameter>m</parameter> passed to the callback is only borrowed, that is, the callback should
+ not call <citerefentry><refentrytitle>sd_bus_message_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ on it. If the callback wants to hold on to the message beyond the lifetime of the callback, it needs to call
+ <citerefentry><refentrytitle>sd_bus_message_ref</refentrytitle><manvolnum>3</manvolnum></citerefentry> to create a
+ new reference.</para>
+
+ <para>If an error occurs during the callback invocation, the callback should return a negative error number
+ (optionally, a more precise error may be returned in <parameter>ret_error</parameter>, as well). If it wants other
+ callbacks that match the same rule to be called, it should return 0. Otherwise it should return a positive integer.
</para>
- <para>
- The message <parameter>m</parameter> passed to the callback is only
- borrowed, that is, the callback should not call
- <citerefentry><refentrytitle>sd_bus_message_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- on it. If the callback wants to hold on to the message beyond the lifetime
- of the callback, it needs to call
- <citerefentry><refentrytitle>sd_bus_message_ref</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- to create a new reference.
- </para>
-
- <para>
- If an error occurs during the callback invocation, the callback should
- return a negative error number. If it wants other callbacks that match the
- same rule to be called, it should return 0. Otherwise it should return a
- positive integer.
- </para>
+ <para>If the <parameter>bus</parameter> refers to a direct connection (i.e. not a bus connection, as set with
+ <citerefentry><refentrytitle>sd_bus_set_bus_client</refentrytitle><manvolnum>3</manvolnum></citerefentry>) the
+ match is only installed on the client side, and the synchronous and asynchronous functions operate the same.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>
- On success, <function>sd_bus_add_match()</function> returns 0 or a
- positive integer. On failure, it returns a negative errno-style error
- code.
+ On success, <function>sd_bus_add_match()</function> and the other calls return 0 or a positive integer. On
+ failure, they return a negative errno-style error code.
</para>
</refsect1>
+ <refsect1>
+ <title>Notes</title>
+
+ <xi:include href="libsystemd-pkgconfig.xml" xpointer="pkgconfig-text"/>
+ </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_slot_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_bus_message_ref</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_bus_set_bus_client</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_bus_slot_set_floating</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
projects / thirdparty / systemd.git / blobdiff