systemd-stable/man/sd_bus_new.xml

<?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">

<!--
This file is part of systemd.

Copyright 2014 Zbigniew Jędrzejewski-Szmek

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.

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.

You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->

<refentry id="sd_bus_new">

  <refentryinfo>
    <title>sd_bus_new</title>
    <productname>systemd</productname>

    <authorgroup>
      <author>
        <contrib>A monkey with a typewriter</contrib>
        <firstname>Zbigniew</firstname>
        <surname>Jędrzejewski-Szmek</surname>
        <email>zbyszek@in.waw.pl</email>
      </author>
    </authorgroup>
  </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>

    <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>
    </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.</para>

    <para><function>sd_bus_ref()</function> creates a new reference to
    <parameter>bus</parameter>. This bus object will not be destroyed
    until <function>sd_bus_unref()</function> has been called as many
    times plus once more. Once the reference count has dropped to
    zero, <parameter>bus</parameter> 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_unref()</function> destroys a reference to
    <parameter>bus</parameter>.</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> always returns
    <constant>NULL</constant>.</para>
  </refsect1>

  <refsect1>
    <title>Errors</title>

    <para>Returned errors may indicate the following problems:</para>

    <variablelist>
      <varlistentry>
        <term><varname>-ENOMEM</varname></term>

        <listitem><para>Memory allocation failed.</para></listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Notes</title>

    <para><function>sd_bus_new()</function> and other functions
    described here 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_open_user</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_open_system</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>
    </para>
  </refsect1>

</refentry>