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+<?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 -->
+
+<refentry id="sd_bus_new" xmlns:xi="http://www.w3.org/2001/XInclude">
+
+ <refentryinfo>
+ <title>sd_bus_new</title>
+ <productname>systemd</productname>
+ </refentryinfo>
+
+ <refmeta>
+ <refentrytitle>sd_bus_new</refentrytitle>
+ <manvolnum>3</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+ <refname>sd_bus_new</refname>
+ <refname>sd_bus_ref</refname>
+ <refname>sd_bus_unref</refname>
+ <refname>sd_bus_unrefp</refname>
+ <refname>sd_bus_close_unref</refname>
+ <refname>sd_bus_close_unrefp</refname>
+ <refname>sd_bus_flush_close_unref</refname>
+ <refname>sd_bus_flush_close_unrefp</refname>
+
+ <refpurpose>Create a new bus object and create or destroy references to it</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
+
+ <funcprototype>
+ <funcdef>int <function>sd_bus_new</function></funcdef>
+ <paramdef>sd_bus **<parameter>bus</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>sd_bus *<function>sd_bus_ref</function></funcdef>
+ <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>sd_bus *<function>sd_bus_unref</function></funcdef>
+ <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>sd_bus *<function>sd_bus_close_unref</function></funcdef>
+ <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>sd_bus *<function>sd_bus_flush_close_unref</function></funcdef>
+ <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>void <function>sd_bus_unrefp</function></funcdef>
+ <paramdef>sd_bus **<parameter>busp</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>void <function>sd_bus_close_unrefp</function></funcdef>
+ <paramdef>sd_bus **<parameter>busp</parameter></paramdef>
+ </funcprototype>
+
+ <funcprototype>
+ <funcdef>void <function>sd_bus_flush_close_unrefp</function></funcdef>
+ <paramdef>sd_bus **<parameter>busp</parameter></paramdef>
+ </funcprototype>
+ </funcsynopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para><function>sd_bus_new()</function> creates a new bus
+ object. This object is reference-counted, and will be destroyed
+ when all references are gone. Initially, the caller of this
+ function owns the sole reference and the bus object will not be
+ connected to any bus. To connect it to a bus, make sure
+ to set an address with
+ <citerefentry><refentrytitle>sd_bus_set_address</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ or a related call, and then start the connection with
+ <citerefentry><refentrytitle>sd_bus_start</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
+
+ <para>In most cases, it is better to use
+ <citerefentry><refentrytitle>sd_bus_default_user</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_bus_default_system</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ or related calls instead of the more low-level <function>sd_bus_new()</function> and
+ <function>sd_bus_start()</function>. The higher-level functions not only allocate a bus object but also
+ start the connection to a well-known bus in a single function call.</para>
+
+ <para><function>sd_bus_ref()</function> increases the reference
+ counter of <parameter>bus</parameter> by one.</para>
+
+ <para><function>sd_bus_unref()</function> decreases the reference
+ counter of <parameter>bus</parameter> by one. Once the reference
+ count has dropped to zero, <parameter>bus</parameter> is destroyed
+ and cannot be used anymore, so further calls to
+ <function>sd_bus_ref()</function> or
+ <function>sd_bus_unref()</function> are illegal.</para>
+
+ <para><function>sd_bus_unrefp()</function> is similar to
+ <function>sd_bus_unref()</function> but takes a pointer to a
+ pointer to an <type>sd_bus</type> object. This call is useful in
+ conjunction with GCC's and LLVM's <ulink
+ url="https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html">Clean-up
+ Variable Attribute</ulink>. Note that this function is defined as an
+ inline function. Use a declaration like the following, in order to
+ allocate a bus object that is freed automatically as the code
+ block is left:</para>
+
+ <programlisting>{
+ __attribute__((cleanup(sd_bus_unrefp))) sd_bus *bus = NULL;
+ int r;
+ …
+ r = sd_bus_default(&amp;bus);
+ if (r &lt; 0) {
+ errno = -r;
+ fprintf(stderr, "Failed to allocate bus: %m\n");
+ }
+ …
+}</programlisting>
+
+ <para><function>sd_bus_ref()</function> and <function>sd_bus_unref()</function> execute no operation if
+ the argument is <constant>NULL</constant>. <function>sd_bus_unrefp()</function> will first dereference
+ its argument, which must not be <constant>NULL</constant>, and will execute no operation if
+ <emphasis>that</emphasis> is <constant>NULL</constant>.</para>
+
+ <para><function>sd_bus_close_unref()</function> is similar to <function>sd_bus_unref()</function>, but
+ first executes
+ <citerefentry><refentrytitle>sd_bus_close</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ ensuring that the connection is terminated before the reference to the connection is dropped and possibly
+ the object freed.</para>
+
+ <para><function>sd_bus_flush_close_unref()</function> is similar to <function>sd_bus_unref()</function>,
+ but first executes
+ <citerefentry><refentrytitle>sd_bus_flush</refentrytitle><manvolnum>3</manvolnum></citerefentry> as well
+ as <citerefentry><refentrytitle>sd_bus_close</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ ensuring that any pending messages are synchronously flushed out before the reference to the connection
+ is dropped and possibly the object freed. This call is particularly useful immediately before exiting
+ from a program as it ensures that any pending outgoing messages are written out, and unprocessed but
+ queued incoming messages released before the connection is terminated and released.</para>
+
+ <para><function>sd_bus_close_unrefp()</function> is similar to
+ <function>sd_bus_close_unref()</function>, but may be used in GCC's and LLVM's Clean-up Variable
+ Attribute, see above. Similarly, <function>sd_bus_flush_close_unrefp()</function> is similar to
+ <function>sd_bus_flush_close_unref()</function>.</para>
+ </refsect1>
+
+ <refsect1>
+ <title>Return Value</title>
+
+ <para>On success, <function>sd_bus_new()</function> returns 0 or a
+ positive integer. On failure, it returns a negative errno-style
+ error code.</para>
+
+ <para><function>sd_bus_ref()</function> always returns the argument.
+ </para>
+
+ <para><function>sd_bus_unref()</function> and <function>sd_bus_flush_close_unref()</function> always return
+ <constant>NULL</constant>.</para>
+
+ <refsect2>
+ <title>Errors</title>
+
+ <para>Returned errors may indicate the following problems:</para>
+
+ <variablelist>
+ <varlistentry>
+ <term><constant>-ENOMEM</constant></term>
+
+ <listitem><para>Memory allocation failed.</para></listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect2>
+ </refsect1>
+
+ <xi:include href="libsystemd-pkgconfig.xml" />
+
+ <refsect1>
+ <title>History</title>
+ <para><function>sd_bus_new()</function>,
+ <function>sd_bus_ref()</function>, and
+ <function>sd_bus_unref()</function> were added in version 209.</para>
+ <para><function>sd_bus_unrefp()</function> was added in version 229.</para>
+ <para><function>sd_bus_flush_close_unref()</function> and
+ <function>sd_bus_flush_close_unrefp()</function> were added in version 240.</para>
+ <para><function>sd_bus_close_unref()</function> and
+ <function>sd_bus_close_unrefp()</function> were added in version 241.</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_default_user</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_bus_default_system</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_bus_open_user</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_bus_open_system</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_bus_close</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ </para>
+ </refsect1>
+
+</refentry>