systemd/man/sd_bus_process.xml

<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

<!--
  SPDX-License-Identifier: LGPL-2.1+

  This file is part of systemd.

  Copyright 2016 Julian Orth

  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_process">

  <refentryinfo>
    <title>sd_bus_process</title>
    <productname>systemd</productname>

    <authorgroup>
      <author>
        <firstname>Julian</firstname>
        <surname>Orth</surname>
        <email>ju.orth@gmail.com</email>
      </author>
    </authorgroup>
  </refentryinfo>

  <refmeta>
    <refentrytitle>sd_bus_process</refentrytitle>
    <manvolnum>3</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>sd_bus_process</refname>

    <refpurpose>Drive the connection</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <funcsynopsis>
      <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>

      <funcprototype>
        <funcdef>int <function>sd_bus_process</function></funcdef>
        <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
        <paramdef>sd_bus_message **<parameter>r</parameter></paramdef>
      </funcprototype>
    </funcsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para>
      <function>sd_bus_process()</function> drives the connection between the
      message bus and the client. That is, it handles connecting,
      authentication, and message processing. It should be called in a loop
      until no further progress can be made or an error occurs.
    </para>

    <para>
      Once no further progress can be made,
      <citerefentry><refentrytitle>sd_bus_wait</refentrytitle><manvolnum>3</manvolnum></citerefentry>
      should be called. Alternatively the user can wait for incoming data on
      the file descriptor returned by
      <citerefentry><refentrytitle>sd_bus_get_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
    </para>

    <para>
      <function>sd_bus_process</function> processes at most one incoming
      message per call.  If the parameter <parameter>r</parameter> is not NULL
      and the call processed a message, <code>*r</code> is set to this message.
      The caller owns a reference to this message and should call
      <citerefentry><refentrytitle>sd_bus_message_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>
      when the message is no longer needed. If <parameter>r</parameter> is not
      NULL, progress was made, but no message was processed, <code>*r</code> is
      set to NULL.
    </para>
  </refsect1>

  <refsect1>
    <title>Return Value</title>

    <para>
      If progress was made, a positive integer is returned. If no progress was
      made, 0 is returned. If an error occurs, a negative errno-style error code
      is returned.
    </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>,
    </para>
  </refsect1>

</refentry>