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<?xml version='1.0'?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="sd_bus_message_dump"
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd_bus_message_dump</title>
<productname>systemd</productname>
</refentryinfo>
<refmeta>
<refentrytitle>sd_bus_message_dump</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_bus_message_dump</refname>
<refname>sd_bus_message_dump_json</refname>
<refpurpose>Produce a string representation of a message for debugging purposes</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
<funcprototype>
<funcdef>int sd_bus_message_dump</funcdef>
<paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
<paramdef>FILE *<parameter>f</parameter></paramdef>
<paramdef>uint64_t <parameter>flags</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int sd_bus_message_dump_json</funcdef>
<paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
<paramdef>uint64_t <parameter>flags</parameter></paramdef>
<paramdef>sd_json_variant **<parameter>ret</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>The <function>sd_bus_message_dump()</function> function writes a textual representation of the
message <parameter>m</parameter> to the stream <parameter>f</parameter>. If <parameter>f</parameter> is
<constant>NULL</constant>, standard output (<constant>stdio</constant>) will be used. This function is
intended to be used for debugging purposes, and the output is neither stable nor designed to be machine
readable.</para>
<para>The <function>sd_bus_message_dump_json()</function> function converts the DBus message
<parameter>m</parameter> to a JSON variant and stores it in <parameter>ret</parameter>. The caller should
call <function>sd_json_variant_unref()</function> for the acquired JSON variant after use. Unlike
<function>sd_bus_message_dump()</function>, the function itself does not print anything. To print the
DBus message in the JSON format, please pass the returned JSON variant to
<function>sd_json_variant_dump()</function>.</para>
<para>The <parameter>flags</parameter> parameter may be used to modify the output, and is a combination
of zero or more of the following flags:</para>
<variablelist>
<varlistentry>
<term><constant>SD_BUS_MESSAGE_DUMP_WITH_HEADER</constant></term>
<listitem><para>The header of the message that specifies the message type, flags, and several more
additional metadata will be printed or included in the resulting JSON object.</para></listitem>
</varlistentry>
<varlistentry>
<term><constant>SD_BUS_MESSAGE_DUMP_SUBTREE_ONLY</constant></term>
<listitem><para>Only the current container will be printed or converted. When the flag is
<emphasis>not</emphasis> specified, the contents of the whole message will be printed or converted.
</para></listitem>
</varlistentry>
</variablelist>
<para>Note that these functions move the read pointer of the message. It may be necessary to reset the
position afterwards, for example with
<citerefentry><refentrytitle>sd_bus_message_rewind</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
</para>
</refsect1>
<refsect1>
<title>Examples</title>
<para>Output for a signal message (with <constant>SD_BUS_MESSAGE_DUMP_WITH_HEADER</constant>):
<programlisting>
‣ Type=signal Endian=l Flags=1 Version=1 Cookie=22
Path=/value/a Interface=org.freedesktop.DBus.Properties Member=PropertiesChanged
MESSAGE "sa{sv}as" {
STRING "org.freedesktop.systemd.ValueTest";
ARRAY "{sv}" {
DICT_ENTRY "sv" {
STRING "Value";
VARIANT "s" {
STRING "object 0x1e, path /value/a";
};
};
};
ARRAY "s" {
STRING "Value2";
STRING "AnExplicitProperty";
};
};
</programlisting>
</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>On success, this function returns 0 or a positive integer. On failure, it returns a negative
errno-style error code. No error codes are currently defined.</para>
</refsect1>
<xi:include href="libsystemd-pkgconfig.xml" />
<refsect1>
<title>See Also</title>
<para><simplelist type="inline">
<member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
<member><citerefentry><refentrytitle>sd-json</refentrytitle><manvolnum>3</manvolnum></citerefentry></member>
</simplelist></para>
</refsect1>
</refentry>
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