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e382c49f | 1 | <?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> |
2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" | |
3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> | |
4 | ||
5 | <!-- | |
6 | This file is part of systemd. | |
7 | ||
8 | Copyright 2016 Julian Orth | |
9 | ||
10 | systemd is free software; you can redistribute it and/or modify it | |
11 | under the terms of the GNU Lesser General Public License as published by | |
12 | the Free Software Foundation; either version 2.1 of the License, or | |
13 | (at your option) any later version. | |
14 | ||
15 | systemd is distributed in the hope that it will be useful, but | |
16 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
18 | Lesser General Public License for more details. | |
19 | ||
20 | You should have received a copy of the GNU Lesser General Public License | |
21 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
22 | --> | |
23 | ||
24 | <refentry id="sd_bus_message_read_basic"> | |
25 | ||
26 | <refentryinfo> | |
27 | <title>sd_bus_message_read_basic</title> | |
28 | <productname>systemd</productname> | |
29 | ||
30 | <authorgroup> | |
31 | <author> | |
32 | <firstname>Julian</firstname> | |
33 | <surname>Orth</surname> | |
34 | <email>ju.orth@gmail.com</email> | |
35 | </author> | |
36 | </authorgroup> | |
37 | </refentryinfo> | |
38 | ||
39 | <refmeta> | |
40 | <refentrytitle>sd_bus_message_read_basic</refentrytitle> | |
41 | <manvolnum>3</manvolnum> | |
42 | </refmeta> | |
43 | ||
44 | <refnamediv> | |
45 | <refname>sd_bus_message_read_basic</refname> | |
46 | ||
47 | <refpurpose>Read a basic type from a message</refpurpose> | |
48 | </refnamediv> | |
49 | ||
50 | <refsynopsisdiv> | |
51 | <funcsynopsis> | |
52 | <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> | |
53 | ||
54 | <funcprototype> | |
55 | <funcdef>int <function>sd_bus_message_read_basic</function></funcdef> | |
56 | <paramdef>sd_bus_message *<parameter>m</parameter></paramdef> | |
57 | <paramdef>char <parameter>type</parameter></paramdef> | |
58 | <paramdef>void *<parameter>p</parameter></paramdef> | |
59 | </funcprototype> | |
60 | </funcsynopsis> | |
61 | </refsynopsisdiv> | |
62 | ||
63 | <refsect1> | |
64 | <title>Description</title> | |
65 | ||
66 | <para> | |
67 | <function>sd_bus_message_read_basic()</function> reads a basic type from a | |
68 | message and advances the read position in the message. The set of basic | |
69 | types and their ascii codes passed in <parameter>type</parameter> are | |
70 | described in the <ulink | |
71 | url="https://dbus.freedesktop.org/doc/dbus-specification.html">D-Bus | |
72 | Specification</ulink>. | |
73 | </para> | |
74 | ||
75 | <para> | |
76 | If <parameter>p</parameter> is not NULL, it should contain a pointer to an | |
77 | appropriate object. For example, if <parameter>type</parameter> is | |
78 | <constant>'y'</constant>, the object passed in <parameter>p</parameter> | |
79 | should have type <code>uint8_t *</code>. If <parameter>type</parameter> | |
80 | is <constant>'s'</constant>, the object passed in <parameter>p</parameter> | |
81 | should have type <code>const char **</code>. Note that, if the basic type | |
82 | is a pointer (e.g., <code>const char *</code> in the case of a string), | |
83 | the pointer is only borrowed and the contents must be copied if they are | |
84 | to be used after the end of the messages lifetime. Similarly, during the | |
85 | lifetime of such a pointer, the message must not be modified. | |
86 | </para> | |
87 | ||
88 | <para> | |
89 | If there is no object of the specified type at the current position in the | |
90 | message, an error is returned. | |
91 | </para> | |
92 | </refsect1> | |
93 | ||
94 | <refsect1> | |
95 | <title>Return Value</title> | |
96 | ||
97 | <para> | |
98 | On success, <function>sd_bus_message_read_basic()</function> returns 0 or | |
99 | a positive integer. On failure, it returns a negative errno-style error | |
100 | code. | |
101 | </para> | |
102 | </refsect1> | |
103 | ||
104 | <refsect1> | |
105 | <title>See Also</title> | |
106 | ||
107 | <para> | |
108 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
109 | <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
110 | </para> | |
111 | </refsect1> | |
112 | ||
113 | </refentry> |