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Diffstat (limited to 'man/sd_bus_request_name.xml')
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diff --git a/man/sd_bus_request_name.xml b/man/sd_bus_request_name.xml new file mode 100644 index 0000000..4fa2e20 --- /dev/null +++ b/man/sd_bus_request_name.xml @@ -0,0 +1,224 @@ +<?xml version='1.0'?> <!--*-nxml-*--> +<!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_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> + + <xi:include href="sd_bus_add_match.xml" xpointer="sd_bus_message_handler_t"/> + + <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 zero or + more 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> + + <xi:include href="version-info.xml" xpointer="v209"/></listitem> + </varlistentry> + + <varlistentry> + <term><constant>SD_BUS_NAME_REPLACE_EXISTING</constant></term> + + <listitem><para>Take over the name if it was 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> + + <xi:include href="version-info.xml" xpointer="v209"/></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> + + <xi:include href="version-info.xml" xpointer="v209"/></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_request_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> + + <refsect2> + <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> + + <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> + + <listitem><para>The bus connection has been disconnected.</para></listitem> + </varlistentry> + + <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> + </refsect2> + </refsect1> + + <xi:include href="libsystemd-pkgconfig.xml" /> + + <refsect1> + <title>History</title> + <para><function>sd_bus_request_name()</function> and + <function>sd_bus_release_name()</function> were added in version 209.</para> + <para><function>sd_bus_request_name_async()</function> and + <function>sd_bus_release_name_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_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_bus_slot_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |