man/sd_bus_get_current_handler.xml

   1 <?xml version='1.0'?>
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!-- SPDX-License-Identifier: LGPL-2.1+ -->
   5
   6 <refentry id="sd_bus_get_current_handler" xmlns:xi="http://www.w3.org/2001/XInclude">
   7
   8   <refentryinfo>
   9     <title>sd_bus_get_current_handler</title>
  10     <productname>systemd</productname>
  11   </refentryinfo>
  12
  13   <refmeta>
  14     <refentrytitle>sd_bus_get_current_handler</refentrytitle>
  15     <manvolnum>3</manvolnum>
  16   </refmeta>
  17
  18   <refnamediv>
  19     <refname>sd_bus_get_current_handler</refname>
  20     <refname>sd_bus_get_current_message</refname>
  21     <refname>sd_bus_get_current_slot</refname>
  22     <refname>sd_bus_get_current_userdata</refname>
  23
  24     <refpurpose>Query information of the callback a bus object is currently running</refpurpose>
  25   </refnamediv>
  26
  27   <refsynopsisdiv>
  28     <funcsynopsis>
  29       <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
  30
  31       <funcprototype>
  32         <funcdef>sd_bus_message_handler_t <function>sd_bus_get_current_handler</function></funcdef>
  33         <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
  34       </funcprototype>
  35
  36       <funcprototype>
  37         <funcdef>sd_bus_message* <function>sd_bus_get_current_message</function></funcdef>
  38         <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
  39       </funcprototype>
  40
  41       <funcprototype>
  42         <funcdef>sd_bus_slot* <function>sd_bus_get_current_slot</function></funcdef>
  43         <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
  44       </funcprototype>
  45
  46       <funcprototype>
  47         <funcdef>void* <function>sd_bus_get_current_userdata</function></funcdef>
  48         <paramdef>sd_bus *<parameter>bus</parameter></paramdef>
  49       </funcprototype>
  50     </funcsynopsis>
  51   </refsynopsisdiv>
  52
  53   <refsect1>
  54     <title>Description</title>
  55
  56     <para>Whenever sd-bus is about to invoke a user-supplied callback function, it stores the
  57     current callback, D-Bus message, slot and userdata pointer and allows these to be queried via
  58     <function>sd_bus_get_current_handler()</function>,
  59     <function>sd_bus_get_current_message()</function>,
  60     <function>sd_bus_get_current_slot()</function> and
  61     <function>sd_bus_get_current_userdata()</function>, respectively. If <parameter>bus</parameter>
  62     cannot be resolved or if execution does not reside in a user-supplied callback of
  63     <parameter>bus</parameter>, these functions return <constant>NULL</constant>.</para>
  64   </refsect1>
  65
  66   <refsect1>
  67     <title>Return Value</title>
  68
  69     <para>On success, these functions return the requested object. On failure, they return
  70     <constant>NULL</constant>.</para>
  71   </refsect1>
  72
  73   <xi:include href="libsystemd-pkgconfig.xml" />
  74
  75   <refsect1>
  76     <title>See Also</title>
  77
  78     <para>
  79       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  80       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>
  81     </para>
  82   </refsect1>
  83
  84 </refentry>