core: introduce new Type=exec service type

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

<?xml version='1.0'?>
<!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+

  Copyright © 2016 Julian Orth
-->

<refentry id="sd_bus_get_fd">

  <refentryinfo>
    <title>sd_bus_get_fd</title>
    <productname>systemd</productname>
  </refentryinfo>

  <refmeta>
    <refentrytitle>sd_bus_get_fd</refentrytitle>
    <manvolnum>3</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>sd_bus_get_fd</refname>

    <refpurpose>Get the file descriptor connected to the message bus</refpurpose>
  </refnamediv>

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

      <funcprototype>
        <funcdef>int <function>sd_bus_get_fd</function></funcdef>
        <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
      </funcprototype>
    </funcsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para>
      <function>sd_bus_get_fd()</function> returns the file descriptor used to
      communicate with the message bus. This descriptor can be used with
      <citerefentry
        project='die-net'><refentrytitle>select</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry
        project='die-net'><refentrytitle>poll</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      or similar functions to wait for incoming messages.
    </para>

    <para>
      If the bus was created with the
      <citerefentry><refentrytitle>sd_bus_set_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>
      function, then the <parameter>input_fd</parameter> used in that call is
      returned.
    </para>
  </refsect1>

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

    <para>
      Returns the file descriptor used for incoming messages from the message
      bus.
    </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_set_fd</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
    </para>
  </refsect1>

</refentry>