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+ -->
   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>. This function is intended to be
  48     used for debugging purposes, and the output is neither stable nor designed to be machine readable.
  49     </para>
  50
  51     <para>The <parameter>flags</parameter> parameter may be used to modify the output. With
  52     <constant>SD_BUS_MESSAGE_DUMP_WITH_HEADER</constant>, a header that specifies the message type and flags
  53     and some additional metadata is printed. When <constant>SD_BUS_MESSAGE_DUMP_SUBTREE_ONLY</constant> is
  54     not passed, the contents of the whole message are printed. When it <emphasis>is</emphasis> passed,
  55     only the current container in printed.</para>
  56
  57     <para>Note that this function moves the read pointer of the message. It may be necessary to reset the
  58     position afterwards, for example with
  59     <citerefentry><refentrytitle>sd_bus_message_rewind</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
  60     </para>
  61   </refsect1>
  62
  63   <refsect1>
  64     <title>Examples</title>
  65
  66     <para>Output for a signal message (with <constant>SD_BUS_MESSAGE_DUMP_WITH_HEADER</constant>):
  67     <programlisting>
  68 ‣ Type=signal  Endian=l  Flags=1  Version=1  Cookie=22
  69   Path=/value/a  Interface=org.freedesktop.DBus.Properties  Member=PropertiesChanged
  70   MESSAGE "sa{sv}as" {
  71           STRING "org.freedesktop.systemd.ValueTest";
  72           ARRAY "{sv}" {
  73                   DICT_ENTRY "sv" {
  74                           STRING "Value";
  75                           VARIANT "s" {
  76                                   STRING "object 0x1e, path /value/a";
  77                           };
  78                   };
  79           };
  80           ARRAY "s" {
  81                   STRING "Value2";
  82                   STRING "AnExplicitProperty";
  83           };
  84   };
  85     </programlisting>
  86     </para>
  87   </refsect1>
  88
  89   <refsect1>
  90     <title>Return Value</title>
  91
  92     <para>On success, this function returns 0 or a positive integer. On failure, it returns a negative
  93     errno-style error code. No error codes are currently defined.</para>
  94   </refsect1>
  95
  96   <xi:include href="libsystemd-pkgconfig.xml" />
  97
  98   <refsect1>
  99     <title>See Also</title>
 100
 101     <para>
 102       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 103       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 104     </para>
 105   </refsect1>
 106
 107 </refentry>