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diff --git a/man/sd_bus_add_match.xml b/man/sd_bus_add_match.xml new file mode 100644 index 0000000..15376d4 --- /dev/null +++ b/man/sd_bus_add_match.xml @@ -0,0 +1,178 @@ +<?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 + + Copyright © 2016 Julian Orth +--> + +<refentry id="sd_bus_add_match" xmlns:xi="http://www.w3.org/2001/XInclude"> + + <refentryinfo> + <title>sd_bus_add_match</title> + <productname>systemd</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>sd_bus_add_match</refentrytitle> + <manvolnum>3</manvolnum> + </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 incoming message dispatching</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> + + <funcprototype id="sd_bus_message_handler_t"> + <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> + <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>void *<parameter>userdata</parameter></paramdef> + </funcprototype> + + <funcprototype> + <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> + </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> 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 each 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 similarly to + <function>sd_bus_add_match()</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>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> and the other calls return 0 or a positive integer. On + failure, they return a negative errno-style error code. + </para> + </refsect1> + + <xi:include href="libsystemd-pkgconfig.xml" /> + + <refsect1> + <title>History</title> + <para><function>sd_bus_add_match()</function> and + <function>sd_bus_message_handler_t()</function> were added in version 231.</para> + <para><function>sd_bus_add_match_async()</function>, + <function>sd_bus_match_signal()</function>, and + <function>sd_bus_match_signal_async()</function> were added in version 237.</para> + </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> + +</refentry> |