man/sd_bus_message_dump.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-or-later -->
   5
   6 <refentry id="sd_bus_message_dump"
   7           xmlns:xi="http://www.w3.org/2001/XInclude">
   8
   9   <refentryinfo>
  10     <title>sd_bus_message_dump</title>
  11     <productname>systemd</productname>
  12   </refentryinfo>
  13
  14   <refmeta>
  15     <refentrytitle>sd_bus_message_dump</refentrytitle>
  16     <manvolnum>3</manvolnum>
  17   </refmeta>
  18
  19   <refnamediv>
  20     <refname>sd_bus_message_dump</refname>
  21
  22     <refpurpose>Produce a string representation of a message for debugging purposes</refpurpose>
  23   </refnamediv>
  24
  25   <refsynopsisdiv>
  26     <funcsynopsis>
  27       <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
  28
  29       <funcprototype>
  30         <funcdef>int sd_bus_message_dump</funcdef>
  31         <paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
  32         <paramdef>FILE *<parameter>f</parameter></paramdef>
  33         <paramdef>uint64_t <parameter>flags</parameter></paramdef>
  34       </funcprototype>
  35     </funcsynopsis>
  36
  37     <para>
  38       <constant>SD_BUS_MESSAGE_DUMP_WITH_HEADER</constant>,
  39       <constant>SD_BUS_MESSAGE_DUMP_SUBTREE_ONLY</constant>
  40     </para>
  41   </refsynopsisdiv>
  42
  43   <refsect1>
  44     <title>Description</title>
  45
  46     <para>The <function>sd_bus_message_dump()</function> function writes a textual representation of the
  47     message <parameter>m</parameter> to the stream <parameter>f</parameter>. If <parameter>f</parameter> is
  48     <constant>NULL</constant>, standard output (<constant>stdio</constant>) will be used. This function is
  49     intended to be used for debugging purposes, and the output is neither stable nor designed to be machine
  50     readable.</para>
  51
  52     <para>The <parameter>flags</parameter> parameter may be used to modify the output. With
  53     <constant>SD_BUS_MESSAGE_DUMP_WITH_HEADER</constant>, a header that specifies the message type and flags
  54     and some additional metadata is printed. When <constant>SD_BUS_MESSAGE_DUMP_SUBTREE_ONLY</constant> is
  55     not passed, the contents of the whole message are printed. When it <emphasis>is</emphasis> passed,
  56     only the current container in printed.</para>
  57
  58     <para>Note that this function moves the read pointer of the message. It may be necessary to reset the
  59     position afterwards, for example with
  60     <citerefentry><refentrytitle>sd_bus_message_rewind</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
  61     </para>
  62   </refsect1>
  63
  64   <refsect1>
  65     <title>Examples</title>
  66
  67     <para>Output for a signal message (with <constant>SD_BUS_MESSAGE_DUMP_WITH_HEADER</constant>):
  68     <programlisting>
  69 ‣ Type=signal  Endian=l  Flags=1  Version=1  Cookie=22
  70   Path=/value/a  Interface=org.freedesktop.DBus.Properties  Member=PropertiesChanged
  71   MESSAGE "sa{sv}as" {
  72           STRING "org.freedesktop.systemd.ValueTest";
  73           ARRAY "{sv}" {
  74                   DICT_ENTRY "sv" {
  75                           STRING "Value";
  76                           VARIANT "s" {
  77                                   STRING "object 0x1e, path /value/a";
  78                           };
  79                   };
  80           };
  81           ARRAY "s" {
  82                   STRING "Value2";
  83                   STRING "AnExplicitProperty";
  84           };
  85   };
  86     </programlisting>
  87     </para>
  88   </refsect1>
  89
  90   <refsect1>
  91     <title>Return Value</title>
  92
  93     <para>On success, this function returns 0 or a positive integer. On failure, it returns a negative
  94     errno-style error code. No error codes are currently defined.</para>
  95   </refsect1>
  96
  97   <xi:include href="libsystemd-pkgconfig.xml" />
  98
  99   <refsect1>
 100     <title>See Also</title>
 101
 102     <para>
 103       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 104       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 105     </para>
 106   </refsect1>
 107
 108 </refentry>