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514094f9 | 1 | <?xml version='1.0'?> |
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"> |
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4 | |
5 | <!-- | |
572eb058 | 6 | SPDX-License-Identifier: LGPL-2.1+ |
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7 | --> |
8 | ||
7d6b2723 | 9 | <refentry id="sd_bus_message_append_basic" xmlns:xi="http://www.w3.org/2001/XInclude"> |
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10 | |
11 | <refentryinfo> | |
12 | <title>sd_bus_message_append_basic</title> | |
13 | <productname>systemd</productname> | |
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14 | </refentryinfo> |
15 | ||
16 | <refmeta> | |
17 | <refentrytitle>sd_bus_message_append_basic</refentrytitle> | |
18 | <manvolnum>3</manvolnum> | |
19 | </refmeta> | |
20 | ||
21 | <refnamediv> | |
22 | <refname>sd_bus_message_append_basic</refname> | |
23 | ||
e8216945 | 24 | <refpurpose>Attach a single field to a message</refpurpose> |
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25 | </refnamediv> |
26 | ||
27 | <refsynopsisdiv> | |
28 | <funcsynopsis> | |
29 | <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> | |
30 | ||
31 | <funcprototype> | |
32 | <funcdef>int sd_bus_message_append_basic</funcdef> | |
33 | <paramdef>sd_bus_message *<parameter>m</parameter></paramdef> | |
34 | <paramdef>char <parameter>type</parameter></paramdef> | |
e8216945 | 35 | <paramdef>const void *<parameter>p</parameter></paramdef> |
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36 | </funcprototype> |
37 | </funcsynopsis> | |
38 | </refsynopsisdiv> | |
39 | ||
40 | <refsect1> | |
41 | <title>Description</title> | |
42 | ||
e8216945 LP |
43 | <para><function>sd_bus_message_append_basic()</function> appends a |
44 | single field to the message <parameter>m</parameter>. The | |
45 | parameter <parameter>type</parameter> determines how the pointer | |
effbc8e4 | 46 | <parameter>p</parameter> is interpreted. |
e8216945 LP |
47 | <parameter>type</parameter> must be one of the basic types as |
48 | defined by the <ulink | |
49 | url="http://dbus.freedesktop.org/doc/dbus-specification.html#basic-types">Basic | |
50 | Types</ulink> section of the D-Bus specification, and listed in | |
51 | the table below. | |
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52 | </para> |
53 | ||
54 | <table id='format-specifiers'> | |
e8216945 | 55 | <title>Item type specifiers</title> |
effbc8e4 | 56 | |
e8216945 | 57 | <tgroup cols='5'> |
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58 | <colspec colname='specifier' /> |
59 | <colspec colname='constant' /> | |
60 | <colspec colname='description' /> | |
61 | <colspec colname='size' /> | |
e8216945 | 62 | <colspec colname='ctype' /> |
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63 | <thead> |
64 | <row> | |
65 | <entry>Specifier</entry> | |
66 | <entry>Constant</entry> | |
67 | <entry>Description</entry> | |
68 | <entry>Size</entry> | |
e8216945 | 69 | <entry>Expected C Type</entry> |
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70 | </row> |
71 | </thead> | |
72 | <tbody> | |
73 | <row> | |
74 | <entry><literal>y</literal></entry> | |
75 | <entry><constant>SD_BUS_TYPE_BYTE</constant></entry> | |
06b643e7 | 76 | <entry>unsigned integer</entry> |
effbc8e4 | 77 | <entry>1 byte</entry> |
e8216945 | 78 | <entry>uint8_t</entry> |
effbc8e4 ZJS |
79 | </row> |
80 | ||
81 | <row> | |
82 | <entry><literal>b</literal></entry> | |
83 | <entry><constant>SD_BUS_TYPE_BOOLEAN</constant></entry> | |
84 | <entry>boolean</entry> | |
85 | <entry>4 bytes</entry> | |
e8216945 | 86 | <entry>int</entry> |
effbc8e4 ZJS |
87 | </row> |
88 | ||
89 | <row> | |
90 | <entry><literal>n</literal></entry> | |
91 | <entry><constant>SD_BUS_TYPE_INT16</constant></entry> | |
92 | <entry>signed integer</entry> | |
93 | <entry>2 bytes</entry> | |
e8216945 | 94 | <entry>int16_t</entry> |
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95 | </row> |
96 | ||
97 | <row> | |
98 | <entry><literal>q</literal></entry> | |
99 | <entry><constant>SD_BUS_TYPE_UINT16</constant></entry> | |
100 | <entry>unsigned integer</entry> | |
101 | <entry>2 bytes</entry> | |
e8216945 | 102 | <entry>uint16_t</entry> |
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103 | </row> |
104 | ||
105 | <row> | |
106 | <entry><literal>i</literal></entry> | |
107 | <entry><constant>SD_BUS_TYPE_INT32</constant></entry> | |
108 | <entry>signed integer</entry> | |
109 | <entry>4 bytes</entry> | |
e8216945 | 110 | <entry>int32_t</entry> |
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111 | </row> |
112 | ||
113 | <row> | |
114 | <entry><literal>u</literal></entry> | |
115 | <entry><constant>SD_BUS_TYPE_UINT32</constant></entry> | |
116 | <entry>unsigned integer</entry> | |
117 | <entry>4 bytes</entry> | |
e8216945 | 118 | <entry>uint32_t</entry> |
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119 | </row> |
120 | ||
121 | <row> | |
122 | <entry><literal>x</literal></entry> | |
123 | <entry><constant>SD_BUS_TYPE_INT64</constant></entry> | |
124 | <entry>signed integer</entry> | |
125 | <entry>8 bytes</entry> | |
e8216945 | 126 | <entry>int64_t</entry> |
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127 | </row> |
128 | ||
129 | <row> | |
130 | <entry><literal>t</literal></entry> | |
131 | <entry><constant>SD_BUS_TYPE_UINT64</constant></entry> | |
132 | <entry>unsigned integer</entry> | |
133 | <entry>8 bytes</entry> | |
e8216945 | 134 | <entry>uint64_t</entry> |
effbc8e4 ZJS |
135 | </row> |
136 | ||
137 | <row> | |
138 | <entry><literal>d</literal></entry> | |
139 | <entry><constant>SD_BUS_TYPE_DOUBLE</constant></entry> | |
140 | <entry>floating-point</entry> | |
141 | <entry>8 bytes</entry> | |
e8216945 | 142 | <entry>double</entry> |
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143 | </row> |
144 | ||
145 | <row> | |
146 | <entry><literal>s</literal></entry> | |
147 | <entry><constant>SD_BUS_TYPE_STRING</constant></entry> | |
148 | <entry>Unicode string</entry> | |
149 | <entry>variable</entry> | |
e8216945 | 150 | <entry>char[]</entry> |
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151 | </row> |
152 | ||
153 | <row> | |
154 | <entry><literal>o</literal></entry> | |
155 | <entry><constant>SD_BUS_TYPE_OBJECT_PATH</constant></entry> | |
156 | <entry>object path</entry> | |
157 | <entry>variable</entry> | |
e8216945 | 158 | <entry>char[]</entry> |
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159 | </row> |
160 | ||
161 | <row> | |
162 | <entry><literal>g</literal></entry> | |
163 | <entry><constant>SD_BUS_TYPE_SIGNATURE</constant></entry> | |
164 | <entry>signature</entry> | |
165 | <entry>variable</entry> | |
e8216945 | 166 | <entry>char[]</entry> |
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167 | </row> |
168 | ||
169 | <row> | |
170 | <entry><literal>h</literal></entry> | |
171 | <entry><constant>SD_BUS_TYPE_UNIX_FD</constant></entry> | |
172 | <entry>UNIX file descriptor</entry> | |
173 | <entry>4 bytes</entry> | |
e8216945 | 174 | <entry>int</entry> |
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175 | </row> |
176 | </tbody> | |
177 | </tgroup> | |
178 | </table> | |
179 | ||
e8216945 LP |
180 | <para>The value of the parameter is copied into a memory area held |
181 | by the message object, stays in the possession of the caller and | |
182 | may hence be freely changed after this call without affecting the | |
183 | bus message it has been added to. If <parameter>type</parameter> | |
184 | is <literal>h</literal> (UNIX file descriptor), the descriptor is | |
185 | duplicated by this call and the passed descriptor stays in | |
186 | possession of the caller.</para> | |
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187 | |
188 | <para>For types <literal>s</literal>, <literal>o</literal>, and | |
189 | <literal>g</literal>, the parameter <parameter>p</parameter> is | |
190 | interpreted as a pointer to a <constant>NUL</constant>-terminated | |
191 | character sequence. As a special case, a <constant>NULL</constant> | |
192 | pointer is interpreted as an empty string. The string should be | |
193 | valid Unicode string encoded as UTF-8. In case of the two latter | |
b8bde116 | 194 | types, the additional requirements for a D-Bus object path or |
effbc8e4 | 195 | type signature should be satisfied. Those requirements should be |
06b643e7 | 196 | verified by the recipient of the message. |
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197 | </para> |
198 | </refsect1> | |
199 | ||
200 | <refsect1> | |
201 | <title>Return Value</title> | |
202 | ||
203 | <para>On success, this call returns 0 or a positive integer. On | |
204 | failure, it returns a negative errno-style error code.</para> | |
205 | </refsect1> | |
206 | ||
207 | <refsect1 id='errors'> | |
208 | <title>Errors</title> | |
209 | ||
210 | <para>Returned errors may indicate the following problems:</para> | |
211 | ||
212 | <variablelist> | |
213 | ||
214 | <varlistentry> | |
8474b70c | 215 | <term><constant>-EINVAL</constant></term> |
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216 | |
217 | <listitem><para>Specified parameter is invalid. | |
218 | </para></listitem> | |
219 | </varlistentry> | |
220 | ||
221 | <varlistentry> | |
8474b70c | 222 | <term><constant>-EPERM</constant></term> |
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223 | |
224 | <listitem><para>Message has been sealed. | |
225 | </para></listitem> | |
226 | </varlistentry> | |
227 | ||
228 | <varlistentry> | |
8474b70c | 229 | <term><constant>-ESTALE</constant></term> |
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230 | |
231 | <listitem><para>Message is in invalid state. | |
232 | </para></listitem> | |
233 | </varlistentry> | |
234 | ||
235 | <varlistentry> | |
8474b70c | 236 | <term><constant>-ENXIO</constant></term> |
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237 | |
238 | <listitem><para>Message cannot be appended to. | |
239 | </para></listitem> | |
240 | </varlistentry> | |
241 | ||
242 | <varlistentry> | |
8474b70c | 243 | <term><constant>-ENOMEM</constant></term> |
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244 | |
245 | <listitem><para>Memory allocation failed.</para></listitem> | |
246 | </varlistentry> | |
247 | </variablelist> | |
248 | </refsect1> | |
249 | ||
7d6b2723 | 250 | <xi:include href="libsystemd-pkgconfig.xml" /> |
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251 | |
252 | <refsect1> | |
253 | <title>See Also</title> | |
254 | ||
255 | <para> | |
256 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
257 | <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
258 | <citerefentry><refentrytitle>sd_bus_message_append</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
259 | <ulink url="http://dbus.freedesktop.org/doc/dbus-specification.html">The D-Bus specification</ulink> | |
260 | </para> | |
261 | </refsect1> | |
262 | ||
263 | </refentry> |