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3802a3d3 | 1 | <?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> |
effbc8e4 | 2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" |
12b42c76 | 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
effbc8e4 ZJS |
4 | |
5 | <!-- | |
572eb058 ZJS |
6 | SPDX-License-Identifier: LGPL-2.1+ |
7 | ||
b975b0d5 | 8 | This file is part of systemd. |
effbc8e4 | 9 | |
b975b0d5 | 10 | Copyright 2014 Zbigniew Jędrzejewski-Szmek |
effbc8e4 | 11 | |
b975b0d5 ZJS |
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. | |
effbc8e4 | 16 | |
b975b0d5 ZJS |
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. | |
effbc8e4 | 21 | |
b975b0d5 ZJS |
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/>. | |
effbc8e4 ZJS |
24 | --> |
25 | ||
48f69d8f | 26 | <refentry id="sd_bus_message_append_basic"> |
effbc8e4 ZJS |
27 | |
28 | <refentryinfo> | |
29 | <title>sd_bus_message_append_basic</title> | |
30 | <productname>systemd</productname> | |
31 | ||
32 | <authorgroup> | |
33 | <author> | |
34 | <contrib>A monkey with a typewriter</contrib> | |
35 | <firstname>Zbigniew</firstname> | |
36 | <surname>Jędrzejewski-Szmek</surname> | |
37 | <email>zbyszek@in.waw.pl</email> | |
38 | </author> | |
39 | </authorgroup> | |
40 | </refentryinfo> | |
41 | ||
42 | <refmeta> | |
43 | <refentrytitle>sd_bus_message_append_basic</refentrytitle> | |
44 | <manvolnum>3</manvolnum> | |
45 | </refmeta> | |
46 | ||
47 | <refnamediv> | |
48 | <refname>sd_bus_message_append_basic</refname> | |
49 | ||
e8216945 | 50 | <refpurpose>Attach a single field to a message</refpurpose> |
effbc8e4 ZJS |
51 | </refnamediv> |
52 | ||
53 | <refsynopsisdiv> | |
54 | <funcsynopsis> | |
55 | <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> | |
56 | ||
57 | <funcprototype> | |
58 | <funcdef>int sd_bus_message_append_basic</funcdef> | |
59 | <paramdef>sd_bus_message *<parameter>m</parameter></paramdef> | |
60 | <paramdef>char <parameter>type</parameter></paramdef> | |
e8216945 | 61 | <paramdef>const void *<parameter>p</parameter></paramdef> |
effbc8e4 ZJS |
62 | </funcprototype> |
63 | </funcsynopsis> | |
64 | </refsynopsisdiv> | |
65 | ||
66 | <refsect1> | |
67 | <title>Description</title> | |
68 | ||
e8216945 LP |
69 | <para><function>sd_bus_message_append_basic()</function> appends a |
70 | single field to the message <parameter>m</parameter>. The | |
71 | parameter <parameter>type</parameter> determines how the pointer | |
effbc8e4 | 72 | <parameter>p</parameter> is interpreted. |
e8216945 LP |
73 | <parameter>type</parameter> must be one of the basic types as |
74 | defined by the <ulink | |
75 | url="http://dbus.freedesktop.org/doc/dbus-specification.html#basic-types">Basic | |
76 | Types</ulink> section of the D-Bus specification, and listed in | |
77 | the table below. | |
effbc8e4 ZJS |
78 | </para> |
79 | ||
80 | <table id='format-specifiers'> | |
e8216945 | 81 | <title>Item type specifiers</title> |
effbc8e4 | 82 | |
e8216945 | 83 | <tgroup cols='5'> |
effbc8e4 ZJS |
84 | <colspec colname='specifier' /> |
85 | <colspec colname='constant' /> | |
86 | <colspec colname='description' /> | |
87 | <colspec colname='size' /> | |
e8216945 | 88 | <colspec colname='ctype' /> |
effbc8e4 ZJS |
89 | <thead> |
90 | <row> | |
91 | <entry>Specifier</entry> | |
92 | <entry>Constant</entry> | |
93 | <entry>Description</entry> | |
94 | <entry>Size</entry> | |
e8216945 | 95 | <entry>Expected C Type</entry> |
effbc8e4 ZJS |
96 | </row> |
97 | </thead> | |
98 | <tbody> | |
99 | <row> | |
100 | <entry><literal>y</literal></entry> | |
101 | <entry><constant>SD_BUS_TYPE_BYTE</constant></entry> | |
06b643e7 | 102 | <entry>unsigned integer</entry> |
effbc8e4 | 103 | <entry>1 byte</entry> |
e8216945 | 104 | <entry>uint8_t</entry> |
effbc8e4 ZJS |
105 | </row> |
106 | ||
107 | <row> | |
108 | <entry><literal>b</literal></entry> | |
109 | <entry><constant>SD_BUS_TYPE_BOOLEAN</constant></entry> | |
110 | <entry>boolean</entry> | |
111 | <entry>4 bytes</entry> | |
e8216945 | 112 | <entry>int</entry> |
effbc8e4 ZJS |
113 | </row> |
114 | ||
115 | <row> | |
116 | <entry><literal>n</literal></entry> | |
117 | <entry><constant>SD_BUS_TYPE_INT16</constant></entry> | |
118 | <entry>signed integer</entry> | |
119 | <entry>2 bytes</entry> | |
e8216945 | 120 | <entry>int16_t</entry> |
effbc8e4 ZJS |
121 | </row> |
122 | ||
123 | <row> | |
124 | <entry><literal>q</literal></entry> | |
125 | <entry><constant>SD_BUS_TYPE_UINT16</constant></entry> | |
126 | <entry>unsigned integer</entry> | |
127 | <entry>2 bytes</entry> | |
e8216945 | 128 | <entry>uint16_t</entry> |
effbc8e4 ZJS |
129 | </row> |
130 | ||
131 | <row> | |
132 | <entry><literal>i</literal></entry> | |
133 | <entry><constant>SD_BUS_TYPE_INT32</constant></entry> | |
134 | <entry>signed integer</entry> | |
135 | <entry>4 bytes</entry> | |
e8216945 | 136 | <entry>int32_t</entry> |
effbc8e4 ZJS |
137 | </row> |
138 | ||
139 | <row> | |
140 | <entry><literal>u</literal></entry> | |
141 | <entry><constant>SD_BUS_TYPE_UINT32</constant></entry> | |
142 | <entry>unsigned integer</entry> | |
143 | <entry>4 bytes</entry> | |
e8216945 | 144 | <entry>uint32_t</entry> |
effbc8e4 ZJS |
145 | </row> |
146 | ||
147 | <row> | |
148 | <entry><literal>x</literal></entry> | |
149 | <entry><constant>SD_BUS_TYPE_INT64</constant></entry> | |
150 | <entry>signed integer</entry> | |
151 | <entry>8 bytes</entry> | |
e8216945 | 152 | <entry>int64_t</entry> |
effbc8e4 ZJS |
153 | </row> |
154 | ||
155 | <row> | |
156 | <entry><literal>t</literal></entry> | |
157 | <entry><constant>SD_BUS_TYPE_UINT64</constant></entry> | |
158 | <entry>unsigned integer</entry> | |
159 | <entry>8 bytes</entry> | |
e8216945 | 160 | <entry>uint64_t</entry> |
effbc8e4 ZJS |
161 | </row> |
162 | ||
163 | <row> | |
164 | <entry><literal>d</literal></entry> | |
165 | <entry><constant>SD_BUS_TYPE_DOUBLE</constant></entry> | |
166 | <entry>floating-point</entry> | |
167 | <entry>8 bytes</entry> | |
e8216945 | 168 | <entry>double</entry> |
effbc8e4 ZJS |
169 | </row> |
170 | ||
171 | <row> | |
172 | <entry><literal>s</literal></entry> | |
173 | <entry><constant>SD_BUS_TYPE_STRING</constant></entry> | |
174 | <entry>Unicode string</entry> | |
175 | <entry>variable</entry> | |
e8216945 | 176 | <entry>char[]</entry> |
effbc8e4 ZJS |
177 | </row> |
178 | ||
179 | <row> | |
180 | <entry><literal>o</literal></entry> | |
181 | <entry><constant>SD_BUS_TYPE_OBJECT_PATH</constant></entry> | |
182 | <entry>object path</entry> | |
183 | <entry>variable</entry> | |
e8216945 | 184 | <entry>char[]</entry> |
effbc8e4 ZJS |
185 | </row> |
186 | ||
187 | <row> | |
188 | <entry><literal>g</literal></entry> | |
189 | <entry><constant>SD_BUS_TYPE_SIGNATURE</constant></entry> | |
190 | <entry>signature</entry> | |
191 | <entry>variable</entry> | |
e8216945 | 192 | <entry>char[]</entry> |
effbc8e4 ZJS |
193 | </row> |
194 | ||
195 | <row> | |
196 | <entry><literal>h</literal></entry> | |
197 | <entry><constant>SD_BUS_TYPE_UNIX_FD</constant></entry> | |
198 | <entry>UNIX file descriptor</entry> | |
199 | <entry>4 bytes</entry> | |
e8216945 | 200 | <entry>int</entry> |
effbc8e4 ZJS |
201 | </row> |
202 | </tbody> | |
203 | </tgroup> | |
204 | </table> | |
205 | ||
e8216945 LP |
206 | <para>The value of the parameter is copied into a memory area held |
207 | by the message object, stays in the possession of the caller and | |
208 | may hence be freely changed after this call without affecting the | |
209 | bus message it has been added to. If <parameter>type</parameter> | |
210 | is <literal>h</literal> (UNIX file descriptor), the descriptor is | |
211 | duplicated by this call and the passed descriptor stays in | |
212 | possession of the caller.</para> | |
effbc8e4 ZJS |
213 | |
214 | <para>For types <literal>s</literal>, <literal>o</literal>, and | |
215 | <literal>g</literal>, the parameter <parameter>p</parameter> is | |
216 | interpreted as a pointer to a <constant>NUL</constant>-terminated | |
217 | character sequence. As a special case, a <constant>NULL</constant> | |
218 | pointer is interpreted as an empty string. The string should be | |
219 | valid Unicode string encoded as UTF-8. In case of the two latter | |
b8bde116 | 220 | types, the additional requirements for a D-Bus object path or |
effbc8e4 | 221 | type signature should be satisfied. Those requirements should be |
06b643e7 | 222 | verified by the recipient of the message. |
effbc8e4 ZJS |
223 | </para> |
224 | </refsect1> | |
225 | ||
226 | <refsect1> | |
227 | <title>Return Value</title> | |
228 | ||
229 | <para>On success, this call returns 0 or a positive integer. On | |
230 | failure, it returns a negative errno-style error code.</para> | |
231 | </refsect1> | |
232 | ||
233 | <refsect1 id='errors'> | |
234 | <title>Errors</title> | |
235 | ||
236 | <para>Returned errors may indicate the following problems:</para> | |
237 | ||
238 | <variablelist> | |
239 | ||
240 | <varlistentry> | |
8474b70c | 241 | <term><constant>-EINVAL</constant></term> |
effbc8e4 ZJS |
242 | |
243 | <listitem><para>Specified parameter is invalid. | |
244 | </para></listitem> | |
245 | </varlistentry> | |
246 | ||
247 | <varlistentry> | |
8474b70c | 248 | <term><constant>-EPERM</constant></term> |
effbc8e4 ZJS |
249 | |
250 | <listitem><para>Message has been sealed. | |
251 | </para></listitem> | |
252 | </varlistentry> | |
253 | ||
254 | <varlistentry> | |
8474b70c | 255 | <term><constant>-ESTALE</constant></term> |
effbc8e4 ZJS |
256 | |
257 | <listitem><para>Message is in invalid state. | |
258 | </para></listitem> | |
259 | </varlistentry> | |
260 | ||
261 | <varlistentry> | |
8474b70c | 262 | <term><constant>-ENXIO</constant></term> |
effbc8e4 ZJS |
263 | |
264 | <listitem><para>Message cannot be appended to. | |
265 | </para></listitem> | |
266 | </varlistentry> | |
267 | ||
268 | <varlistentry> | |
8474b70c | 269 | <term><constant>-ENOMEM</constant></term> |
effbc8e4 ZJS |
270 | |
271 | <listitem><para>Memory allocation failed.</para></listitem> | |
272 | </varlistentry> | |
273 | </variablelist> | |
274 | </refsect1> | |
275 | ||
276 | <refsect1> | |
277 | <title>Notes</title> | |
278 | ||
b8bde116 | 279 | <para>The <function>sd_bus_append_basic()</function> function |
effbc8e4 ZJS |
280 | described here is available as a shared library, which can be |
281 | compiled and linked to with the | |
5aded369 | 282 | <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
effbc8e4 ZJS |
283 | file.</para> |
284 | </refsect1> | |
285 | ||
286 | <refsect1> | |
287 | <title>See Also</title> | |
288 | ||
289 | <para> | |
290 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
291 | <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
292 | <citerefentry><refentrytitle>sd_bus_message_append</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
293 | <ulink url="http://dbus.freedesktop.org/doc/dbus-specification.html">The D-Bus specification</ulink> | |
294 | </para> | |
295 | </refsect1> | |
296 | ||
297 | </refentry> |