<?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">
+ "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
- This file is part of systemd.
+ SPDX-License-Identifier: LGPL-2.1+
+-->
- Copyright 2013 Lennart Poettering
+<refentry id="sd_bus_request_name"
+ xmlns:xi="http://www.w3.org/2001/XInclude">
+
+ <refentryinfo>
+ <title>sd_bus_request_name</title>
+ <productname>systemd</productname>
+ </refentryinfo>
+
+ <refmeta>
+ <refentrytitle>sd_bus_request_name</refentrytitle>
+ <manvolnum>3</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+ <refname>sd_bus_request_name</refname>
+ <refname>sd_bus_request_name_async</refname>
+ <refname>sd_bus_release_name</refname>
+ <refname>sd_bus_release_name_async</refname>
+ <refpurpose>Request or release a well-known service name on a bus</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
+
+ <funcprototype>
+ <funcdef>int <function>sd_bus_request_name</function></funcdef>
+ <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
+ <paramdef>const char *<parameter>name</parameter></paramdef>
+ <paramdef>uint64_t <parameter>flags</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>int <function>sd_bus_request_name_async</function></funcdef>
+ <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
+ <paramdef>sd_bus_slot **<parameter>slot</parameter></paramdef>
+ <paramdef>const char *<parameter>name</parameter></paramdef>
+ <paramdef>uint64_t <parameter>flags</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_release_name</function></funcdef>
+ <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
+ <paramdef>const char *<parameter>name</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>int <function>sd_bus_release_name_async</function></funcdef>
+ <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
+ <paramdef>sd_bus_slot **<parameter>slot</parameter></paramdef>
+ <paramdef>const char *<parameter>name</parameter></paramdef>
+ <paramdef>sd_bus_message_handler_t <parameter>callback</parameter></paramdef>
+ <paramdef>void *<parameter>userdata</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para><function>sd_bus_request_name()</function> requests a well-known service name on a bus. It takes a bus
+ connection, a valid bus name and a flags parameter. The flags parameter is a combination of the following
+ flags:</para>
+
+ <variablelist>
+ <varlistentry>
+ <term><constant>SD_BUS_NAME_ALLOW_REPLACEMENT</constant></term>
+
+ <listitem><para>After acquiring the name successfully, permit other peers to take over the name when they try
+ to acquire it with the <constant>SD_BUS_NAME_REPLACE_EXISTING</constant> flag set. If
+ <constant>SD_BUS_NAME_ALLOW_REPLACEMENT</constant> is not set on the original request, such a request by other
+ peers will be denied.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>SD_BUS_NAME_REPLACE_EXISTING</constant></term>
+
+ <listitem><para>Take over the name if it is already acquired by another peer, and that other peer has permitted
+ takeover by setting <constant>SD_BUS_NAME_ALLOW_REPLACEMENT</constant> while acquiring it.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>SD_BUS_NAME_QUEUE</constant></term>
+
+ <listitem><para>Queue the acquisition of the name when the name is already taken.</para></listitem>
+ </varlistentry>
+ </variablelist>
+
+ <para><function>sd_bus_request_name()</function> operates in a synchronous fashion: a message requesting the name
+ is sent to the bus broker, and the call waits until the broker responds.</para>
+
+ <para><function>sd_bus_request_name_async()</function> is an asynchronous version of
+ <function>sd_bus_release_name()</function>. Instead of waiting for the request to complete, the request message is
+ enqueued. The specified <parameter>callback</parameter> will be called when the broker's response is received. If
+ the parameter is specified as <constant>NULL</constant> a default implementation is used instead which will
+ terminate the connection when the name cannot be acquired. The function returns a slot object in its
+ <parameter>slot</parameter> parameter — if it is passed as non-<constant>NULL</constant> — which may be used as a
+ reference to the name request operation. Use
+ <citerefentry><refentrytitle>sd_bus_slot_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry> to destroy
+ this reference. Note that destroying the reference will not unregister the name, but simply ensure the specified
+ callback is no longer called.</para>
+
+ <para><function>sd_bus_release_name()</function> releases an acquired well-known name. It takes a bus connection
+ and a valid bus name as parameters. This function operates synchronously, sending a release request message to the
+ bus broker and waiting for it to reply.</para>
+
+ <para><function>sd_bus_release_name_async()</function> is an asynchronous version of
+ <function>sd_bus_release_name()</function>. The specified <parameter>callback</parameter> function is called when
+ the name has been released successfully. If specified as <constant>NULL</constant> a generic implementation is used
+ that ignores the result of the operation. As above, the <parameter>slot</parameter> (if
+ non-<constant>NULL</constant>) is set to an object that may be used to reference the operation.</para>
+
+ <para>These functions are supported only on bus connections, i.e. connections to a bus broker and not on direct
+ connections.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Return Value</title>
+
+ <para>On success, these calls return 0 or a positive integer. On failure, these calls return a negative errno-style
+ error code.</para>
+
+ <para>If <constant>SD_BUS_NAME_QUEUE</constant> is specified, <function>sd_bus_request_name()</function> will return
+ 0 when the name is already taken by another peer and the client has been added to the queue for the name. In that
+ case, the caller can subscribe to <literal>NameOwnerChanged</literal> signals to be notified when the name is
+ successfully acquired. <function>sd_bus_request_name()</function> returns > 0 when the name has immediately
+ been acquired successfully.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Errors</title>
+
+ <para>Returned errors may indicate the following problems:</para>
+
+ <variablelist>
+ <varlistentry>
+ <term><constant>-EALREADY</constant></term>
+
+ <listitem><para>The caller already is the owner of the specified name.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>-EEXIST</constant></term>
+
+ <listitem><para>The name has already been acquired by a different peer, and SD_BUS_NAME_REPLACE_EXISTING was
+ not specified or the other peer did not specify SD_BUS_NAME_ALLOW_REPLACEMENT while acquiring the
+ name.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>-ESRCH</constant></term>
+
+ <listitem><para>It was attempted to release a name that is currently not registered on the
+ bus.</para></listitem>
+ </varlistentry>
- 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.
+ <varlistentry>
+ <term><constant>-EADDRINUSE</constant></term>
+
+ <listitem><para>It was attempted to release a name that is owned by a different peer on the
+ bus.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>-EINVAL</constant></term>
+
+ <listitem><para>A specified parameter is invalid. This is also generated when the requested name is a special
+ service name reserved by the D-Bus specification, or when the operation is requested on a connection that does
+ not refer to a bus.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><constant>-ENOTCONN</constant></term>
- 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.
+ <listitem><para>The bus connection has been disconnected.</para></listitem>
+ </varlistentry>
- You should have received a copy of the GNU Lesser General Public License
- along with systemd; If not, see <http://www.gnu.org/licenses/>.
--->
+ <varlistentry>
+ <term><constant>-ECHILD</constant></term>
+
+ <listitem><para>The bus connection has been created in a different process than the current
+ one.</para></listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <xi:include href="libsystemd-pkgconfig.xml" />
-<refentry id="sd_bus_request_name">
-
- <refentryinfo>
- <title>sd_bus_request_name</title>
- <productname>systemd</productname>
-
- <authorgroup>
- <author>
- <contrib>Developer</contrib>
- <firstname>Lennart</firstname>
- <surname>Poettering</surname>
- <email>lennart@poettering.net</email>
- </author>
- </authorgroup>
- </refentryinfo>
-
- <refmeta>
- <refentrytitle>sd_bus_request_name</refentrytitle>
- <manvolnum>3</manvolnum>
- </refmeta>
-
- <refnamediv>
- <refname>sd_bus_request_name</refname>
- <refname>sd_bus_release_name</refname>
- <refpurpose>Request or release a well-known name on a bus</refpurpose>
- </refnamediv>
-
- <refsynopsisdiv>
- <funcsynopsis>
- <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
-
- <funcprototype>
- <funcdef>int <function>sd_bus_request_name</function></funcdef>
- <paramdef>sd_bus* <parameter>bus</parameter></paramdef>
- <paramdef>const char *<parameter>name</parameter></paramdef>
- <paramdef>uint64_t <parameter>flags</parameter></paramdef>
- </funcprototype>
-
- <funcprototype>
- <funcdef>int <function>sd_bus_release_name</function></funcdef>
- <paramdef>sd_bus* <parameter>bus</parameter></paramdef>
- <paramdef>const char *<parameter>name</parameter></paramdef>
- </funcprototype>
- </funcsynopsis>
- </refsynopsisdiv>
-
- <refsect1>
- <title>Description</title>
-
- <para><function>sd_bus_request_name()</function> requests
- a well-known name on a bus. It takes a bus connection,
- a valid bus name and a flags parameter. The flags
- parameter is a combination of the following
- flags:</para>
-
- <variablelist>
- <varlistentry>
- <term><varname>SD_BUS_NAME_ALLOW_REPLACEMENT</varname></term>
-
- <listitem><para>After acquiring the
- name successuflly, permit other peers
- to take over the name when they try to
- acquire it with the
- <varname>SD_BUS_NAME_REPLACE_EXISTING</varname>
- flag set. If
- <varname>SD_BUS_NAME_ALLOW_REPLACEMENT</varname>
- is not set on the original request
- such a request by other peers will be
- denied.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>SD_BUS_NAME_REPLACE_EXISTING</varname></term>
-
- <listitem><para>Take over a the name
- if it is already acquired by a another
- peer, and that other peer permitted
- taking it over by setting
- <varname>SD_BUS_NAME_ALLOW_REPLACEMENT</varname>
- while acquiring it.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>SD_BUS_NAME_QUEUE</varname></term>
-
- <listitem><para>Queue name
- acquisition when the name is already
- taken.</para></listitem>
- </varlistentry>
- </variablelist>
-
- <para><function>sd_bus_release_name()</function> releases
- an acquired well-known name. It takes a bus connection
- and a valid bus name as parameters.</para>
- </refsect1>
-
- <refsect1>
- <title>Return Value</title>
-
- <para>On success, these calls return 0 or a positive
- integer. On failure, these calls return a negative
- errno-style error code.</para>
-
- <para>If <varname>SD_BUS_NAME_QUEUE</varname> is
- specified <function>sd_bus_request_name()</function>
- will return 0 when the name is already taken by
- another peer and the client has been added to the
- queue for the name. In that case the caller can
- subscribe to <literal>NameOwnerChanged</literal>
- signals to be notified when the name is successfully
- acquired. <function>sd_bus_request_name()</function>
- returns > 0 when the name has immediately been
- acquired successfully.</para>
- </refsect1>
-
- <refsect1>
- <title>Errors</title>
-
- <para>Returned errors may indicate the following problems:</para>
-
- <variablelist>
- <varlistentry>
- <term><varname>-EALREADY</varname></term>
-
- <listitem><para>The caller already is
- the owner of the specified
- name.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>-EEXIST</varname></term>
-
- <listitem><para>The name has already
- been acquired by a different peer, and
- SD_BUS_NAME_REPLACE_EXISTING was not
- specified or the other peer did not
- specify SD_BUS_NAME_ALLOW_REPLACEMENT
- while acquiring the
- name.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>-ESRCH</varname></term>
-
- <listitem><para>It was attemted to
- release a name that is currently not
- registered on the
- bus.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>-EADDRINUSE</varname></term>
-
- <listitem><para>It was attemted to
- release a name that is owned by a
- different peer on the
- bus.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>-EINVAL</varname></term>
-
- <listitem><para>A specified parameter
- is invalid.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>-ENOTCONN</varname></term>
-
- <listitem><para>The bus connection has
- been disconnected.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>-ECHILD</varname></term>
-
- <listitem><para>The bus connection has
- been created in a different process
- than the current.</para></listitem>
- </varlistentry>
- </variablelist>
- </refsect1>
-
- <refsect1>
- <title>Notes</title>
-
- <para>The <function>sd_bus_acquire_name()</function>
- and <function>sd_bus_release_name()</function>
- interfaces are available as a shared library, which can
- be compiled and linked to with the
- <constant>libsystemd-bus</constant> <citerefentry><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-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd_bus_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- </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_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_bus_slot_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ </para>
+ </refsect1>
</refentry>
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