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[thirdparty/systemd.git] / man / sd_bus_process.xml

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<refentry id="sd_bus_process">

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