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_verify_type" xmlns:xi="http://www.w3.org/2001/XInclude">
7  <refentryinfo>
8    <title>sd_bus_message_verify_type</title>
9    <productname>systemd</productname>
10  </refentryinfo>
11
12  <refmeta>
13    <refentrytitle>sd_bus_message_verify_type</refentrytitle>
14    <manvolnum>3</manvolnum>
15  </refmeta>
16
17  <refnamediv>
18    <refname>sd_bus_message_verify_type</refname>
19
20    <refpurpose>Check if the message has specified type at the current location</refpurpose>
21  </refnamediv>
22
23  <refsynopsisdiv>
24    <funcsynopsis>
25      <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
26
27      <funcprototype>
28        <funcdef>int sd_bus_message_verify_type</funcdef>
29        <paramdef>sd_bus_message *<parameter>m</parameter></paramdef>
30        <paramdef>char <parameter>type</parameter></paramdef>
31        <paramdef>const char* <parameter>contents</parameter></paramdef>
32      </funcprototype>
33    </funcsynopsis>
34  </refsynopsisdiv>
35
36  <refsect1>
37    <title>Description</title>
38
39    <para><function>sd_bus_message_verify_type()</function> checks if the complete type at the
40    current location in the message <parameter>m</parameter> matches the specified
41    <parameter>type</parameter> and <parameter>contents</parameter>. If non-zero, parameter
42    <parameter>type</parameter> must be one of the types specified in
43    <citerefentry><refentrytitle>sd_bus_message_append</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
44    If non-null, parameter <parameter>contents</parameter> must be a valid sequence of complete
45    types. If both <parameter>type</parameter> and <parameter>contents</parameter> are specified
46    <parameter>type</parameter> must be a container type.</para>
47
48    <para>If <parameter>type</parameter> is specified, the type in the message must match.  If
49    <parameter>contents</parameter> is specified, the type in the message must be a container type
50    with this signature.</para>
51  </refsect1>
52
53  <refsect1>
54    <title>Return Value</title>
55
56    <para>On success, this call returns true if the type matches and zero if not (the message
57    <parameter>m</parameter> contains different data or the end of the message has been reached). On
58    failure, it returns a negative errno-style error code.</para>
59
60    <refsect2>
61      <title>Errors</title>
62
63      <para>Returned errors may indicate the following problems:</para>
64
65      <variablelist>
66
67        <varlistentry>
68          <term><constant>-EINVAL</constant></term>
69
70          <listitem><para><parameter>m</parameter> or both <parameter>type</parameter> and
71          <parameter>contents</parameter> are <constant>NULL</constant>.</para>
72
73          <para>Arguments do not satisfy other constraints listed above.</para>
74          </listitem>
75        </varlistentry>
76
77        <varlistentry>
78          <term><constant>-EPERM</constant></term>
79
80          <listitem><para>Message <parameter>m</parameter> is not sealed.
81          </para></listitem>
82        </varlistentry>
83      </variablelist>
84    </refsect2>
85  </refsect1>
86
87  <xi:include href="libsystemd-pkgconfig.xml" />
88
89  <refsect1>
90    <title>See Also</title>
91
92    <para>
93      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
94      <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
95      <citerefentry><refentrytitle>sd_bus_message_append</refentrytitle><manvolnum>3</manvolnum></citerefentry>
96    </para>
97  </refsect1>
98
99</refentry>
100