<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>
<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>
+ <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><varname>SD_BUS_NAME_ALLOW_REPLACEMENT</varname></term>
- <listitem><para>After acquiring the name successfully, 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>
+ <listitem><para>After acquiring the name successfully, 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 the name if it is already acquired
- by another peer, and that other peer has permitted takeover by
- setting <varname>SD_BUS_NAME_ALLOW_REPLACEMENT</varname> while
- acquiring it.</para></listitem>
+ <listitem><para>Take over the name if it is already acquired by another peer, and that other peer has permitted
+ takeover 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 the acquisition of the name when the
- name is already taken.</para></listitem>
+ <listitem><para>Queue the acquisition of the name 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>
+ <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 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 <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>
+ <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>
<varlistentry>
<term><constant>-EALREADY</constant></term>
- <listitem><para>The caller already is the owner of the
- specified name.</para></listitem>
+ <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
+ <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>
+ <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>
+ <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>
+ <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>
+ <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>
+ <listitem><para>The bus connection has been created in a different process than the current
+ one.</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</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
- file.</para>
+ <para>The <function>sd_bus_acquire_name()</function> and the other interfaces described here are available as a
+ shared library, which can be compiled and linked to with the <constant>libsystemd</constant> <citerefentry
+ project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> file.</para>
</refsect1>
<refsect1>
<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_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_bus_slot_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
projects / thirdparty / systemd.git / blobdiff