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9c920791 | 1 | <?xml version='1.0'?> <!--*-nxml-*--> |
3a54a157 | 2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
9c920791 ZJS |
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_type" xmlns:xi="http://www.w3.org/2001/XInclude"> | |
7 | ||
8 | <refentryinfo> | |
9 | <title>sd_bus_message_get_type</title> | |
10 | <productname>systemd</productname> | |
11 | </refentryinfo> | |
12 | ||
13 | <refmeta> | |
14 | <refentrytitle>sd_bus_message_get_type</refentrytitle> | |
15 | <manvolnum>3</manvolnum> | |
16 | </refmeta> | |
17 | ||
18 | <refnamediv> | |
19 | <refname>sd_bus_message_get_type</refname> | |
20 | <refname>sd_bus_message_is_signal</refname> | |
21 | <refname>sd_bus_message_is_method_call</refname> | |
22 | <refname>sd_bus_message_is_method_error</refname> | |
23 | ||
24 | <refpurpose>Query bus message addressing metadata</refpurpose> | |
25 | </refnamediv> | |
26 | ||
27 | <refsynopsisdiv> | |
28 | <funcsynopsis> | |
29 | <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> | |
30 | ||
31 | <funcprototype> | |
32 | <funcdef>int <function>sd_bus_message_get_type</function></funcdef> | |
33 | <paramdef>sd_bus_message *<parameter>message</parameter></paramdef> | |
34 | <paramdef>uint8_t *<parameter>type</parameter></paramdef> | |
35 | </funcprototype> | |
36 | ||
37 | <funcprototype> | |
38 | <funcdef>int <function>sd_bus_message_is_signal</function></funcdef> | |
39 | <paramdef>sd_bus_message *<parameter>message</parameter></paramdef> | |
40 | <paramdef>const char *<parameter>interface</parameter></paramdef> | |
41 | <paramdef>const char *<parameter>member</parameter></paramdef> | |
42 | </funcprototype> | |
43 | ||
44 | <funcprototype> | |
45 | <funcdef>int <function>sd_bus_message_is_method_call</function></funcdef> | |
46 | <paramdef>sd_bus_message *<parameter>message</parameter></paramdef> | |
47 | <paramdef>const char *<parameter>interface</parameter></paramdef> | |
48 | <paramdef>const char *<parameter>member</parameter></paramdef> | |
49 | </funcprototype> | |
50 | ||
51 | <funcprototype> | |
52 | <funcdef>int <function>sd_bus_message_is_method_error</function></funcdef> | |
53 | <paramdef>sd_bus_message *<parameter>message</parameter></paramdef> | |
54 | <paramdef>const char *<parameter>name</parameter></paramdef> | |
55 | </funcprototype> | |
56 | </funcsynopsis> | |
57 | ||
58 | </refsynopsisdiv> | |
59 | ||
60 | <refsect1> | |
61 | <title>Description</title> | |
62 | ||
63 | <para><function>sd_bus_message_get_type()</function> returns the type of a message in the output | |
64 | parameter <parameter>type</parameter>, one of <constant>SD_BUS_MESSAGE_METHOD_CALL</constant>, | |
65 | <constant>SD_BUS_MESSAGE_METHOD_RETURN</constant>, | |
66 | <constant>SD_BUS_MESSAGE_METHOD_ERROR</constant>, <constant>SD_BUS_MESSAGE_SIGNAL</constant>. | |
67 | This type is either specified as a parameter when the message is created using | |
68 | <citerefentry><refentrytitle>sd_bus_set_message_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
69 | or is set automatically when the message is created using | |
70 | <citerefentry><refentrytitle>sd_bus_set_message_new_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
71 | <citerefentry><refentrytitle>sd_bus_set_message_new_method_call</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
72 | <citerefentry><refentrytitle>sd_bus_set_message_new_method_error</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
73 | and similar functions. | |
74 | </para> | |
75 | ||
76 | <para><function>sd_bus_message_is_signal()</function> checks if message <parameter>m</parameter> | |
77 | is a signal message. If <parameter>interface</parameter> is non-null, it also checks if the | |
78 | message has the same interface set. If <parameter>member</parameter> is non-null, it also checks | |
79 | if the message has the same member set. Also see | |
80 | <citerefentry><refentrytitle>sd_bus_set_message_new_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry>. It returns true when all checks pass.</para> | |
81 | ||
82 | <para><function>sd_bus_message_is_method_call()</function> checks if message <parameter>m</parameter> | |
83 | is a method call message. If <parameter>interface</parameter> is non-null, it also checks if the | |
84 | message has the same interface set. If <parameter>member</parameter> is non-null, it also checks | |
85 | if the message has the same member set. Also see | |
86 | <citerefentry><refentrytitle>sd_bus_set_message_new_method_call</refentrytitle><manvolnum>3</manvolnum></citerefentry>. It returns true when all checks pass.</para> | |
87 | ||
88 | <para><function>sd_bus_message_is_method_error()</function> checks if message <parameter>m</parameter> | |
89 | is an error reply message. If <parameter>name</parameter> is non-null, it also checks if the | |
90 | message has the same error identifier set. Also see | |
91 | <citerefentry><refentrytitle>sd_bus_set_message_new_method_error</refentrytitle><manvolnum>3</manvolnum></citerefentry>. It returns true when all checks pass.</para> | |
92 | </refsect1> | |
93 | ||
94 | <refsect1> | |
95 | <title>Return Value</title> | |
96 | ||
97 | <para>On success, those functions return 0 or a positive | |
98 | integer. On failure, it returns a negative errno-style error code.</para> | |
9c920791 | 99 | |
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100 | <refsect2> |
101 | <title>Errors</title> | |
9c920791 | 102 | |
b1de39de | 103 | <para>Returned errors may indicate the following problems:</para> |
9c920791 | 104 | |
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105 | <variablelist> |
106 | <varlistentry> | |
107 | <term><constant>-EINVAL</constant></term> | |
9c920791 | 108 | |
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109 | <listitem><para>The <parameter>message</parameter> parameter or the output parameter are |
110 | <constant>NULL</constant>.</para></listitem> | |
111 | </varlistentry> | |
112 | </variablelist> | |
113 | </refsect2> | |
9c920791 ZJS |
114 | </refsect1> |
115 | ||
116 | <xi:include href="libsystemd-pkgconfig.xml" /> | |
117 | ||
118 | <refsect1> | |
119 | <title>See Also</title> | |
120 | ||
121 | <para> | |
122 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
123 | <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
124 | <citerefentry><refentrytitle>sd_bus_message_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
125 | <citerefentry><refentrytitle>sd_bus_message_set_destination</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
126 | </para> | |
127 | </refsect1> | |
128 | ||
129 | </refentry> |