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1 | <?xml version='1.0'?> <!--*-nxml-*--> |
2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//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_get_signature" xmlns:xi="http://www.w3.org/2001/XInclude"> | |
7 | <refentryinfo> | |
8 | <title>sd_bus_message_get_signature</title> | |
9 | <productname>systemd</productname> | |
10 | </refentryinfo> | |
11 | ||
12 | <refmeta> | |
13 | <refentrytitle>sd_bus_message_get_signature</refentrytitle> | |
14 | <manvolnum>3</manvolnum> | |
15 | </refmeta> | |
16 | ||
17 | <refnamediv> | |
18 | <refname>sd_bus_message_get_signature</refname> | |
19 | <refname>sd_bus_message_is_empty</refname> | |
20 | <refname>sd_bus_message_has_signature</refname> | |
21 | ||
22 | <refpurpose>Query bus message signature</refpurpose> | |
23 | </refnamediv> | |
24 | ||
25 | <refsynopsisdiv> | |
26 | <funcsynopsis> | |
27 | <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> | |
28 | ||
29 | <funcprototype> | |
30 | <funcdef>const char* <function>sd_bus_message_get_signature</function></funcdef> | |
31 | <paramdef>sd_bus_message *<parameter>message</parameter></paramdef> | |
32 | <paramdef>int <parameter>complete</parameter></paramdef> | |
33 | </funcprototype> | |
34 | ||
35 | <funcprototype> | |
36 | <funcdef>int <function>sd_bus_message_is_empty</function></funcdef> | |
37 | <paramdef>sd_bus_message *<parameter>message</parameter></paramdef> | |
38 | </funcprototype> | |
39 | ||
40 | <funcprototype> | |
41 | <funcdef>int <function>sd_bus_message_has_signature</function></funcdef> | |
42 | <paramdef>sd_bus_message *<parameter>message</parameter></paramdef> | |
43 | <paramdef>const char *<parameter>signature</parameter></paramdef> | |
44 | </funcprototype> | |
45 | </funcsynopsis> | |
46 | ||
47 | </refsynopsisdiv> | |
48 | ||
49 | <refsect1> | |
50 | <title>Description</title> | |
51 | ||
52 | <para><function>sd_bus_message_get_signature()</function> returns the signature of message | |
53 | <parameter>message</parameter>. If <parameter>complete</parameter> is true, the signature of the | |
54 | whole message is returned, and just the signature of the currently open container otherwise. | |
55 | </para> | |
56 | ||
57 | <para><function>sd_bus_message_is_empty()</function> returns true if the message is empty, | |
58 | i.e. when its signature is empty.</para> | |
59 | ||
60 | <para><function>sd_bus_message_has_signature()</function> returns true if the signature of the | |
61 | message <parameter>message</parameter> matches given <parameter>signature</parameter>. Parameter | |
62 | <parameter>signature</parameter> may be <constant>NULL</constant>, this is treated the same as | |
63 | an empty string, which is equivalent to calling <function>sd_bus_message_is_empty()</function>. | |
64 | </para> | |
65 | </refsect1> | |
66 | ||
67 | <refsect1> | |
68 | <title>Return Value</title> | |
69 | ||
70 | <para>On success, <function>sd_bus_message_get_signature()</function> returns | |
71 | the signature, and <constant>NULL</constant> on error.</para> | |
72 | ||
73 | <para>The other functions return 0 or a positive integer on success. On failure, they return a | |
74 | negative errno-style error code.</para> | |
75 | </refsect1> | |
76 | ||
77 | <refsect1> | |
78 | <title>Errors</title> | |
79 | ||
80 | <para>Returned errors may indicate the following problems:</para> | |
81 | ||
82 | <variablelist> | |
83 | <varlistentry> | |
84 | <term><constant>-EINVAL</constant></term> | |
85 | ||
86 | <listitem><para>The <parameter>message</parameter> parameter is <constant>NULL</constant>. | |
87 | </para></listitem> | |
88 | </varlistentry> | |
89 | ||
90 | <varlistentry> | |
91 | <term><constant>NULL</constant></term> | |
92 | ||
93 | <listitem><para>The <parameter>message</parameter> parameter is <constant>NULL</constant>. | |
94 | </para></listitem> | |
95 | </varlistentry> | |
96 | </variablelist> | |
97 | </refsect1> | |
98 | ||
99 | <xi:include href="libsystemd-pkgconfig.xml" /> | |
100 | ||
101 | <refsect1> | |
102 | <title>See Also</title> | |
103 | ||
104 | <para> | |
105 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
106 | <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
107 | <citerefentry><refentrytitle>sd_bus_message_new</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
108 | </para> | |
109 | </refsect1> | |
110 | ||
111 | </refentry> |