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f47781d8 | 1 | <?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*--> |
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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 | <!-- | |
e735f4d4 | 6 | This file is part of systemd. |
60f067b4 | 7 | |
e735f4d4 | 8 | Copyright 2014 Zbigniew Jędrzejewski-Szmek |
60f067b4 | 9 | |
e735f4d4 MP |
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. | |
60f067b4 | 14 | |
e735f4d4 MP |
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. | |
60f067b4 | 19 | |
e735f4d4 MP |
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/>. | |
60f067b4 JS |
22 | --> |
23 | ||
86f210e9 | 24 | <refentry id="sd_bus_message_append_basic"> |
60f067b4 JS |
25 | |
26 | <refentryinfo> | |
27 | <title>sd_bus_message_append_basic</title> | |
28 | <productname>systemd</productname> | |
29 | ||
30 | <authorgroup> | |
31 | <author> | |
32 | <contrib>A monkey with a typewriter</contrib> | |
33 | <firstname>Zbigniew</firstname> | |
34 | <surname>Jędrzejewski-Szmek</surname> | |
35 | <email>zbyszek@in.waw.pl</email> | |
36 | </author> | |
37 | </authorgroup> | |
38 | </refentryinfo> | |
39 | ||
40 | <refmeta> | |
41 | <refentrytitle>sd_bus_message_append_basic</refentrytitle> | |
42 | <manvolnum>3</manvolnum> | |
43 | </refmeta> | |
44 | ||
45 | <refnamediv> | |
46 | <refname>sd_bus_message_append_basic</refname> | |
47 | ||
7035cd9e | 48 | <refpurpose>Attach a single field to a message</refpurpose> |
60f067b4 JS |
49 | </refnamediv> |
50 | ||
51 | <refsynopsisdiv> | |
52 | <funcsynopsis> | |
53 | <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> | |
54 | ||
55 | <funcprototype> | |
56 | <funcdef>int sd_bus_message_append_basic</funcdef> | |
57 | <paramdef>sd_bus_message *<parameter>m</parameter></paramdef> | |
58 | <paramdef>char <parameter>type</parameter></paramdef> | |
7035cd9e | 59 | <paramdef>const void *<parameter>p</parameter></paramdef> |
60f067b4 JS |
60 | </funcprototype> |
61 | </funcsynopsis> | |
62 | </refsynopsisdiv> | |
63 | ||
64 | <refsect1> | |
65 | <title>Description</title> | |
66 | ||
7035cd9e MP |
67 | <para><function>sd_bus_message_append_basic()</function> appends a |
68 | single field to the message <parameter>m</parameter>. The | |
69 | parameter <parameter>type</parameter> determines how the pointer | |
60f067b4 | 70 | <parameter>p</parameter> is interpreted. |
7035cd9e MP |
71 | <parameter>type</parameter> must be one of the basic types as |
72 | defined by the <ulink | |
73 | url="http://dbus.freedesktop.org/doc/dbus-specification.html#basic-types">Basic | |
74 | Types</ulink> section of the D-Bus specification, and listed in | |
75 | the table below. | |
60f067b4 JS |
76 | </para> |
77 | ||
78 | <table id='format-specifiers'> | |
7035cd9e | 79 | <title>Item type specifiers</title> |
60f067b4 | 80 | |
7035cd9e | 81 | <tgroup cols='5'> |
60f067b4 JS |
82 | <colspec colname='specifier' /> |
83 | <colspec colname='constant' /> | |
84 | <colspec colname='description' /> | |
85 | <colspec colname='size' /> | |
7035cd9e | 86 | <colspec colname='ctype' /> |
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87 | <thead> |
88 | <row> | |
89 | <entry>Specifier</entry> | |
90 | <entry>Constant</entry> | |
91 | <entry>Description</entry> | |
92 | <entry>Size</entry> | |
7035cd9e | 93 | <entry>Expected C Type</entry> |
60f067b4 JS |
94 | </row> |
95 | </thead> | |
96 | <tbody> | |
97 | <row> | |
98 | <entry><literal>y</literal></entry> | |
99 | <entry><constant>SD_BUS_TYPE_BYTE</constant></entry> | |
5eef597e | 100 | <entry>unsigned integer</entry> |
60f067b4 | 101 | <entry>1 byte</entry> |
7035cd9e | 102 | <entry>uint8_t</entry> |
60f067b4 JS |
103 | </row> |
104 | ||
105 | <row> | |
106 | <entry><literal>b</literal></entry> | |
107 | <entry><constant>SD_BUS_TYPE_BOOLEAN</constant></entry> | |
108 | <entry>boolean</entry> | |
109 | <entry>4 bytes</entry> | |
7035cd9e | 110 | <entry>int</entry> |
60f067b4 JS |
111 | </row> |
112 | ||
113 | <row> | |
114 | <entry><literal>n</literal></entry> | |
115 | <entry><constant>SD_BUS_TYPE_INT16</constant></entry> | |
116 | <entry>signed integer</entry> | |
117 | <entry>2 bytes</entry> | |
7035cd9e | 118 | <entry>int16_t</entry> |
60f067b4 JS |
119 | </row> |
120 | ||
121 | <row> | |
122 | <entry><literal>q</literal></entry> | |
123 | <entry><constant>SD_BUS_TYPE_UINT16</constant></entry> | |
124 | <entry>unsigned integer</entry> | |
125 | <entry>2 bytes</entry> | |
7035cd9e | 126 | <entry>uint16_t</entry> |
60f067b4 JS |
127 | </row> |
128 | ||
129 | <row> | |
130 | <entry><literal>i</literal></entry> | |
131 | <entry><constant>SD_BUS_TYPE_INT32</constant></entry> | |
132 | <entry>signed integer</entry> | |
133 | <entry>4 bytes</entry> | |
7035cd9e | 134 | <entry>int32_t</entry> |
60f067b4 JS |
135 | </row> |
136 | ||
137 | <row> | |
138 | <entry><literal>u</literal></entry> | |
139 | <entry><constant>SD_BUS_TYPE_UINT32</constant></entry> | |
140 | <entry>unsigned integer</entry> | |
141 | <entry>4 bytes</entry> | |
7035cd9e | 142 | <entry>uint32_t</entry> |
60f067b4 JS |
143 | </row> |
144 | ||
145 | <row> | |
146 | <entry><literal>x</literal></entry> | |
147 | <entry><constant>SD_BUS_TYPE_INT64</constant></entry> | |
148 | <entry>signed integer</entry> | |
149 | <entry>8 bytes</entry> | |
7035cd9e | 150 | <entry>int64_t</entry> |
60f067b4 JS |
151 | </row> |
152 | ||
153 | <row> | |
154 | <entry><literal>t</literal></entry> | |
155 | <entry><constant>SD_BUS_TYPE_UINT64</constant></entry> | |
156 | <entry>unsigned integer</entry> | |
157 | <entry>8 bytes</entry> | |
7035cd9e | 158 | <entry>uint64_t</entry> |
60f067b4 JS |
159 | </row> |
160 | ||
161 | <row> | |
162 | <entry><literal>d</literal></entry> | |
163 | <entry><constant>SD_BUS_TYPE_DOUBLE</constant></entry> | |
164 | <entry>floating-point</entry> | |
165 | <entry>8 bytes</entry> | |
7035cd9e | 166 | <entry>double</entry> |
60f067b4 JS |
167 | </row> |
168 | ||
169 | <row> | |
170 | <entry><literal>s</literal></entry> | |
171 | <entry><constant>SD_BUS_TYPE_STRING</constant></entry> | |
172 | <entry>Unicode string</entry> | |
173 | <entry>variable</entry> | |
7035cd9e | 174 | <entry>char[]</entry> |
60f067b4 JS |
175 | </row> |
176 | ||
177 | <row> | |
178 | <entry><literal>o</literal></entry> | |
179 | <entry><constant>SD_BUS_TYPE_OBJECT_PATH</constant></entry> | |
180 | <entry>object path</entry> | |
181 | <entry>variable</entry> | |
7035cd9e | 182 | <entry>char[]</entry> |
60f067b4 JS |
183 | </row> |
184 | ||
185 | <row> | |
186 | <entry><literal>g</literal></entry> | |
187 | <entry><constant>SD_BUS_TYPE_SIGNATURE</constant></entry> | |
188 | <entry>signature</entry> | |
189 | <entry>variable</entry> | |
7035cd9e | 190 | <entry>char[]</entry> |
60f067b4 JS |
191 | </row> |
192 | ||
193 | <row> | |
194 | <entry><literal>h</literal></entry> | |
195 | <entry><constant>SD_BUS_TYPE_UNIX_FD</constant></entry> | |
196 | <entry>UNIX file descriptor</entry> | |
197 | <entry>4 bytes</entry> | |
7035cd9e | 198 | <entry>int</entry> |
60f067b4 JS |
199 | </row> |
200 | </tbody> | |
201 | </tgroup> | |
202 | </table> | |
203 | ||
7035cd9e MP |
204 | <para>The value of the parameter is copied into a memory area held |
205 | by the message object, stays in the possession of the caller and | |
206 | may hence be freely changed after this call without affecting the | |
207 | bus message it has been added to. If <parameter>type</parameter> | |
208 | is <literal>h</literal> (UNIX file descriptor), the descriptor is | |
209 | duplicated by this call and the passed descriptor stays in | |
210 | possession of the caller.</para> | |
60f067b4 JS |
211 | |
212 | <para>For types <literal>s</literal>, <literal>o</literal>, and | |
213 | <literal>g</literal>, the parameter <parameter>p</parameter> is | |
214 | interpreted as a pointer to a <constant>NUL</constant>-terminated | |
215 | character sequence. As a special case, a <constant>NULL</constant> | |
216 | pointer is interpreted as an empty string. The string should be | |
217 | valid Unicode string encoded as UTF-8. In case of the two latter | |
218 | types, the additional requirements for a D-Bus object path or | |
219 | type signature should be satisfied. Those requirements should be | |
5eef597e | 220 | verified by the recipient of the message. |
60f067b4 JS |
221 | </para> |
222 | </refsect1> | |
223 | ||
224 | <refsect1> | |
225 | <title>Return Value</title> | |
226 | ||
227 | <para>On success, this call returns 0 or a positive integer. On | |
228 | failure, it returns a negative errno-style error code.</para> | |
229 | </refsect1> | |
230 | ||
231 | <refsect1 id='errors'> | |
232 | <title>Errors</title> | |
233 | ||
234 | <para>Returned errors may indicate the following problems:</para> | |
235 | ||
236 | <variablelist> | |
237 | ||
238 | <varlistentry> | |
5eef597e | 239 | <term><constant>-EINVAL</constant></term> |
60f067b4 JS |
240 | |
241 | <listitem><para>Specified parameter is invalid. | |
242 | </para></listitem> | |
243 | </varlistentry> | |
244 | ||
245 | <varlistentry> | |
5eef597e | 246 | <term><constant>-EPERM</constant></term> |
60f067b4 JS |
247 | |
248 | <listitem><para>Message has been sealed. | |
249 | </para></listitem> | |
250 | </varlistentry> | |
251 | ||
252 | <varlistentry> | |
5eef597e | 253 | <term><constant>-ESTALE</constant></term> |
60f067b4 JS |
254 | |
255 | <listitem><para>Message is in invalid state. | |
256 | </para></listitem> | |
257 | </varlistentry> | |
258 | ||
259 | <varlistentry> | |
5eef597e | 260 | <term><constant>-ENXIO</constant></term> |
60f067b4 JS |
261 | |
262 | <listitem><para>Message cannot be appended to. | |
263 | </para></listitem> | |
264 | </varlistentry> | |
265 | ||
266 | <varlistentry> | |
5eef597e | 267 | <term><constant>-ENOMEM</constant></term> |
60f067b4 JS |
268 | |
269 | <listitem><para>Memory allocation failed.</para></listitem> | |
270 | </varlistentry> | |
271 | </variablelist> | |
272 | </refsect1> | |
273 | ||
274 | <refsect1> | |
275 | <title>Notes</title> | |
276 | ||
277 | <para>The <function>sd_bus_append_basic()</function> function | |
278 | described here is available as a shared library, which can be | |
279 | compiled and linked to with the | |
5eef597e | 280 | <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
60f067b4 JS |
281 | file.</para> |
282 | </refsect1> | |
283 | ||
284 | <refsect1> | |
285 | <title>See Also</title> | |
286 | ||
287 | <para> | |
288 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
289 | <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
290 | <citerefentry><refentrytitle>sd_bus_message_append</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
291 | <ulink url="http://dbus.freedesktop.org/doc/dbus-specification.html">The D-Bus specification</ulink> | |
292 | </para> | |
293 | </refsect1> | |
294 | ||
295 | </refentry> |