]>
Commit | Line | Data |
---|---|---|
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 | <!-- | |
572eb058 ZJS |
6 | SPDX-License-Identifier: LGPL-2.1+ |
7 | ||
e382c49f | 8 | This file is part of systemd. |
9 | ||
10 | Copyright 2016 Julian Orth | |
11 | ||
12 | systemd is free software; you can redistribute it and/or modify it | |
13 | under the terms of the GNU Lesser General Public License as published by | |
14 | the Free Software Foundation; either version 2.1 of the License, or | |
15 | (at your option) any later version. | |
16 | ||
17 | systemd is distributed in the hope that it will be useful, but | |
18 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
20 | Lesser General Public License for more details. | |
21 | ||
22 | You should have received a copy of the GNU Lesser General Public License | |
23 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
24 | --> | |
25 | ||
26 | <refentry id="sd_bus_message_read_basic"> | |
27 | ||
28 | <refentryinfo> | |
29 | <title>sd_bus_message_read_basic</title> | |
30 | <productname>systemd</productname> | |
31 | ||
32 | <authorgroup> | |
33 | <author> | |
34 | <firstname>Julian</firstname> | |
35 | <surname>Orth</surname> | |
36 | <email>ju.orth@gmail.com</email> | |
37 | </author> | |
38 | </authorgroup> | |
39 | </refentryinfo> | |
40 | ||
41 | <refmeta> | |
42 | <refentrytitle>sd_bus_message_read_basic</refentrytitle> | |
43 | <manvolnum>3</manvolnum> | |
44 | </refmeta> | |
45 | ||
46 | <refnamediv> | |
47 | <refname>sd_bus_message_read_basic</refname> | |
48 | ||
49 | <refpurpose>Read a basic type from a message</refpurpose> | |
50 | </refnamediv> | |
51 | ||
52 | <refsynopsisdiv> | |
53 | <funcsynopsis> | |
54 | <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> | |
55 | ||
56 | <funcprototype> | |
57 | <funcdef>int <function>sd_bus_message_read_basic</function></funcdef> | |
58 | <paramdef>sd_bus_message *<parameter>m</parameter></paramdef> | |
59 | <paramdef>char <parameter>type</parameter></paramdef> | |
60 | <paramdef>void *<parameter>p</parameter></paramdef> | |
61 | </funcprototype> | |
62 | </funcsynopsis> | |
63 | </refsynopsisdiv> | |
64 | ||
65 | <refsect1> | |
66 | <title>Description</title> | |
67 | ||
68 | <para> | |
69 | <function>sd_bus_message_read_basic()</function> reads a basic type from a | |
70 | message and advances the read position in the message. The set of basic | |
71 | types and their ascii codes passed in <parameter>type</parameter> are | |
72 | described in the <ulink | |
73 | url="https://dbus.freedesktop.org/doc/dbus-specification.html">D-Bus | |
74 | Specification</ulink>. | |
75 | </para> | |
76 | ||
77 | <para> | |
78 | If <parameter>p</parameter> is not NULL, it should contain a pointer to an | |
79 | appropriate object. For example, if <parameter>type</parameter> is | |
80 | <constant>'y'</constant>, the object passed in <parameter>p</parameter> | |
81 | should have type <code>uint8_t *</code>. If <parameter>type</parameter> | |
82 | is <constant>'s'</constant>, the object passed in <parameter>p</parameter> | |
83 | should have type <code>const char **</code>. Note that, if the basic type | |
84 | is a pointer (e.g., <code>const char *</code> in the case of a string), | |
85 | the pointer is only borrowed and the contents must be copied if they are | |
86 | to be used after the end of the messages lifetime. Similarly, during the | |
87 | lifetime of such a pointer, the message must not be modified. | |
88 | </para> | |
89 | ||
90 | <para> | |
91 | If there is no object of the specified type at the current position in the | |
92 | message, an error is returned. | |
93 | </para> | |
94 | </refsect1> | |
95 | ||
96 | <refsect1> | |
97 | <title>Return Value</title> | |
98 | ||
99 | <para> | |
100 | On success, <function>sd_bus_message_read_basic()</function> returns 0 or | |
101 | a positive integer. On failure, it returns a negative errno-style error | |
102 | code. | |
103 | </para> | |
104 | </refsect1> | |
105 | ||
106 | <refsect1> | |
107 | <title>See Also</title> | |
108 | ||
109 | <para> | |
110 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
111 | <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
112 | </para> | |
113 | </refsect1> | |
114 | ||
115 | </refentry> |