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1 | <?xml version='1.0'?> <!--*-nxml-*--> |
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 2014 Zbigniew Jędrzejewski-Szmek | |
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_append_basic" conditional="ENABLE_KDBUS"> | |
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 | ||
48 | <refpurpose>Attach a single part to a message</refpurpose> | |
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> | |
59 | <paramdef>char void *<parameter>p</parameter></paramdef> | |
60 | </funcprototype> | |
61 | </funcsynopsis> | |
62 | </refsynopsisdiv> | |
63 | ||
64 | <refsect1> | |
65 | <title>Description</title> | |
66 | ||
67 | <para><function>sd_bus_message_append_basic</function> appends a | |
68 | single item to the message <parameter>m</parameter>. Parameter | |
69 | <parameter>type</parameter> determines how pointer | |
70 | <parameter>p</parameter> is interpreted. | |
71 | <parameter>type</parameter> must be one of the basic types | |
72 | as defined by the | |
73 | ||
74 | <ulink url="http://dbus.freedesktop.org/doc/dbus-specification.html#basic-types">Basic Types</ulink> | |
75 | section of the D-Bus specification, and listed in the table below. | |
76 | </para> | |
77 | ||
78 | <table id='format-specifiers'> | |
79 | <title>Item format specifiers</title> | |
80 | ||
81 | <tgroup cols='4'> | |
82 | <colspec colname='specifier' /> | |
83 | <colspec colname='constant' /> | |
84 | <colspec colname='description' /> | |
85 | <colspec colname='size' /> | |
86 | <thead> | |
87 | <row> | |
88 | <entry>Specifier</entry> | |
89 | <entry>Constant</entry> | |
90 | <entry>Description</entry> | |
91 | <entry>Size</entry> | |
92 | </row> | |
93 | </thead> | |
94 | <tbody> | |
95 | <row> | |
96 | <entry><literal>y</literal></entry> | |
97 | <entry><constant>SD_BUS_TYPE_BYTE</constant></entry> | |
5eef597e | 98 | <entry>unsigned integer</entry> |
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99 | <entry>1 byte</entry> |
100 | </row> | |
101 | ||
102 | <row> | |
103 | <entry><literal>b</literal></entry> | |
104 | <entry><constant>SD_BUS_TYPE_BOOLEAN</constant></entry> | |
105 | <entry>boolean</entry> | |
106 | <entry>4 bytes</entry> | |
107 | </row> | |
108 | ||
109 | <row> | |
110 | <entry><literal>n</literal></entry> | |
111 | <entry><constant>SD_BUS_TYPE_INT16</constant></entry> | |
112 | <entry>signed integer</entry> | |
113 | <entry>2 bytes</entry> | |
114 | </row> | |
115 | ||
116 | <row> | |
117 | <entry><literal>q</literal></entry> | |
118 | <entry><constant>SD_BUS_TYPE_UINT16</constant></entry> | |
119 | <entry>unsigned integer</entry> | |
120 | <entry>2 bytes</entry> | |
121 | </row> | |
122 | ||
123 | <row> | |
124 | <entry><literal>i</literal></entry> | |
125 | <entry><constant>SD_BUS_TYPE_INT32</constant></entry> | |
126 | <entry>signed integer</entry> | |
127 | <entry>4 bytes</entry> | |
128 | </row> | |
129 | ||
130 | <row> | |
131 | <entry><literal>u</literal></entry> | |
132 | <entry><constant>SD_BUS_TYPE_UINT32</constant></entry> | |
133 | <entry>unsigned integer</entry> | |
134 | <entry>4 bytes</entry> | |
135 | </row> | |
136 | ||
137 | <row> | |
138 | <entry><literal>x</literal></entry> | |
139 | <entry><constant>SD_BUS_TYPE_INT64</constant></entry> | |
140 | <entry>signed integer</entry> | |
141 | <entry>8 bytes</entry> | |
142 | </row> | |
143 | ||
144 | <row> | |
145 | <entry><literal>t</literal></entry> | |
146 | <entry><constant>SD_BUS_TYPE_UINT64</constant></entry> | |
147 | <entry>unsigned integer</entry> | |
148 | <entry>8 bytes</entry> | |
149 | </row> | |
150 | ||
151 | <row> | |
152 | <entry><literal>d</literal></entry> | |
153 | <entry><constant>SD_BUS_TYPE_DOUBLE</constant></entry> | |
154 | <entry>floating-point</entry> | |
155 | <entry>8 bytes</entry> | |
156 | </row> | |
157 | ||
158 | <row> | |
159 | <entry><literal>s</literal></entry> | |
160 | <entry><constant>SD_BUS_TYPE_STRING</constant></entry> | |
161 | <entry>Unicode string</entry> | |
162 | <entry>variable</entry> | |
163 | </row> | |
164 | ||
165 | <row> | |
166 | <entry><literal>o</literal></entry> | |
167 | <entry><constant>SD_BUS_TYPE_OBJECT_PATH</constant></entry> | |
168 | <entry>object path</entry> | |
169 | <entry>variable</entry> | |
170 | </row> | |
171 | ||
172 | <row> | |
173 | <entry><literal>g</literal></entry> | |
174 | <entry><constant>SD_BUS_TYPE_SIGNATURE</constant></entry> | |
175 | <entry>signature</entry> | |
176 | <entry>variable</entry> | |
177 | </row> | |
178 | ||
179 | <row> | |
180 | <entry><literal>h</literal></entry> | |
181 | <entry><constant>SD_BUS_TYPE_UNIX_FD</constant></entry> | |
182 | <entry>UNIX file descriptor</entry> | |
183 | <entry>4 bytes</entry> | |
184 | </row> | |
185 | </tbody> | |
186 | </tgroup> | |
187 | </table> | |
188 | ||
189 | <para>The value of the parameter is copied into the memory area | |
190 | containing the message and may be changed after this call. If | |
191 | <parameter>type</parameter> is <literal>h</literal> (UNIX file | |
192 | descriptor), it is always "consumed" by this call, and either | |
193 | successfully appended to the message or closed.</para> | |
194 | ||
195 | <para>For types <literal>s</literal>, <literal>o</literal>, and | |
196 | <literal>g</literal>, the parameter <parameter>p</parameter> is | |
197 | interpreted as a pointer to a <constant>NUL</constant>-terminated | |
198 | character sequence. As a special case, a <constant>NULL</constant> | |
199 | pointer is interpreted as an empty string. The string should be | |
200 | valid Unicode string encoded as UTF-8. In case of the two latter | |
201 | types, the additional requirements for a D-Bus object path or | |
202 | type signature should be satisfied. Those requirements should be | |
5eef597e | 203 | verified by the recipient of the message. |
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204 | </para> |
205 | </refsect1> | |
206 | ||
207 | <refsect1> | |
208 | <title>Return Value</title> | |
209 | ||
210 | <para>On success, this call returns 0 or a positive integer. On | |
211 | failure, it returns a negative errno-style error code.</para> | |
212 | </refsect1> | |
213 | ||
214 | <refsect1 id='errors'> | |
215 | <title>Errors</title> | |
216 | ||
217 | <para>Returned errors may indicate the following problems:</para> | |
218 | ||
219 | <variablelist> | |
220 | ||
221 | <varlistentry> | |
5eef597e | 222 | <term><constant>-EINVAL</constant></term> |
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223 | |
224 | <listitem><para>Specified parameter is invalid. | |
225 | </para></listitem> | |
226 | </varlistentry> | |
227 | ||
228 | <varlistentry> | |
5eef597e | 229 | <term><constant>-EPERM</constant></term> |
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230 | |
231 | <listitem><para>Message has been sealed. | |
232 | </para></listitem> | |
233 | </varlistentry> | |
234 | ||
235 | <varlistentry> | |
5eef597e | 236 | <term><constant>-ESTALE</constant></term> |
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237 | |
238 | <listitem><para>Message is in invalid state. | |
239 | </para></listitem> | |
240 | </varlistentry> | |
241 | ||
242 | <varlistentry> | |
5eef597e | 243 | <term><constant>-ENXIO</constant></term> |
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244 | |
245 | <listitem><para>Message cannot be appended to. | |
246 | </para></listitem> | |
247 | </varlistentry> | |
248 | ||
249 | <varlistentry> | |
5eef597e | 250 | <term><constant>-ENOMEM</constant></term> |
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251 | |
252 | <listitem><para>Memory allocation failed.</para></listitem> | |
253 | </varlistentry> | |
254 | </variablelist> | |
255 | </refsect1> | |
256 | ||
257 | <refsect1> | |
258 | <title>Notes</title> | |
259 | ||
260 | <para>The <function>sd_bus_append_basic()</function> function | |
261 | described here is available as a shared library, which can be | |
262 | compiled and linked to with the | |
5eef597e | 263 | <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
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264 | file.</para> |
265 | </refsect1> | |
266 | ||
267 | <refsect1> | |
268 | <title>See Also</title> | |
269 | ||
270 | <para> | |
271 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
272 | <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
273 | <citerefentry><refentrytitle>sd_bus_message_append</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
274 | <ulink url="http://dbus.freedesktop.org/doc/dbus-specification.html">The D-Bus specification</ulink> | |
275 | </para> | |
276 | </refsect1> | |
277 | ||
278 | </refentry> |