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514094f9 | 1 | <?xml version='1.0'?> |
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2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> | |
0307f791 | 4 | <!-- SPDX-License-Identifier: LGPL-2.1+ --> |
effbc8e4 | 5 | |
7d6b2723 | 6 | <refentry id="sd_bus_message_append_basic" xmlns:xi="http://www.w3.org/2001/XInclude"> |
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7 | |
8 | <refentryinfo> | |
9 | <title>sd_bus_message_append_basic</title> | |
10 | <productname>systemd</productname> | |
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11 | </refentryinfo> |
12 | ||
13 | <refmeta> | |
14 | <refentrytitle>sd_bus_message_append_basic</refentrytitle> | |
15 | <manvolnum>3</manvolnum> | |
16 | </refmeta> | |
17 | ||
18 | <refnamediv> | |
19 | <refname>sd_bus_message_append_basic</refname> | |
20 | ||
e8216945 | 21 | <refpurpose>Attach a single field to a message</refpurpose> |
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22 | </refnamediv> |
23 | ||
24 | <refsynopsisdiv> | |
25 | <funcsynopsis> | |
26 | <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> | |
27 | ||
28 | <funcprototype> | |
29 | <funcdef>int sd_bus_message_append_basic</funcdef> | |
30 | <paramdef>sd_bus_message *<parameter>m</parameter></paramdef> | |
31 | <paramdef>char <parameter>type</parameter></paramdef> | |
e8216945 | 32 | <paramdef>const void *<parameter>p</parameter></paramdef> |
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33 | </funcprototype> |
34 | </funcsynopsis> | |
35 | </refsynopsisdiv> | |
36 | ||
37 | <refsect1> | |
38 | <title>Description</title> | |
39 | ||
e8216945 LP |
40 | <para><function>sd_bus_message_append_basic()</function> appends a |
41 | single field to the message <parameter>m</parameter>. The | |
42 | parameter <parameter>type</parameter> determines how the pointer | |
effbc8e4 | 43 | <parameter>p</parameter> is interpreted. |
e8216945 LP |
44 | <parameter>type</parameter> must be one of the basic types as |
45 | defined by the <ulink | |
46 | url="http://dbus.freedesktop.org/doc/dbus-specification.html#basic-types">Basic | |
47 | Types</ulink> section of the D-Bus specification, and listed in | |
48 | the table below. | |
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49 | </para> |
50 | ||
51 | <table id='format-specifiers'> | |
e8216945 | 52 | <title>Item type specifiers</title> |
effbc8e4 | 53 | |
e8216945 | 54 | <tgroup cols='5'> |
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55 | <colspec colname='specifier' /> |
56 | <colspec colname='constant' /> | |
57 | <colspec colname='description' /> | |
58 | <colspec colname='size' /> | |
e8216945 | 59 | <colspec colname='ctype' /> |
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60 | <thead> |
61 | <row> | |
62 | <entry>Specifier</entry> | |
63 | <entry>Constant</entry> | |
64 | <entry>Description</entry> | |
65 | <entry>Size</entry> | |
e8216945 | 66 | <entry>Expected C Type</entry> |
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67 | </row> |
68 | </thead> | |
69 | <tbody> | |
70 | <row> | |
71 | <entry><literal>y</literal></entry> | |
72 | <entry><constant>SD_BUS_TYPE_BYTE</constant></entry> | |
06b643e7 | 73 | <entry>unsigned integer</entry> |
effbc8e4 | 74 | <entry>1 byte</entry> |
e8216945 | 75 | <entry>uint8_t</entry> |
effbc8e4 ZJS |
76 | </row> |
77 | ||
78 | <row> | |
79 | <entry><literal>b</literal></entry> | |
80 | <entry><constant>SD_BUS_TYPE_BOOLEAN</constant></entry> | |
81 | <entry>boolean</entry> | |
82 | <entry>4 bytes</entry> | |
e8216945 | 83 | <entry>int</entry> |
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84 | </row> |
85 | ||
86 | <row> | |
87 | <entry><literal>n</literal></entry> | |
88 | <entry><constant>SD_BUS_TYPE_INT16</constant></entry> | |
89 | <entry>signed integer</entry> | |
90 | <entry>2 bytes</entry> | |
e8216945 | 91 | <entry>int16_t</entry> |
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92 | </row> |
93 | ||
94 | <row> | |
95 | <entry><literal>q</literal></entry> | |
96 | <entry><constant>SD_BUS_TYPE_UINT16</constant></entry> | |
97 | <entry>unsigned integer</entry> | |
98 | <entry>2 bytes</entry> | |
e8216945 | 99 | <entry>uint16_t</entry> |
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100 | </row> |
101 | ||
102 | <row> | |
103 | <entry><literal>i</literal></entry> | |
104 | <entry><constant>SD_BUS_TYPE_INT32</constant></entry> | |
105 | <entry>signed integer</entry> | |
106 | <entry>4 bytes</entry> | |
e8216945 | 107 | <entry>int32_t</entry> |
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108 | </row> |
109 | ||
110 | <row> | |
111 | <entry><literal>u</literal></entry> | |
112 | <entry><constant>SD_BUS_TYPE_UINT32</constant></entry> | |
113 | <entry>unsigned integer</entry> | |
114 | <entry>4 bytes</entry> | |
e8216945 | 115 | <entry>uint32_t</entry> |
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116 | </row> |
117 | ||
118 | <row> | |
119 | <entry><literal>x</literal></entry> | |
120 | <entry><constant>SD_BUS_TYPE_INT64</constant></entry> | |
121 | <entry>signed integer</entry> | |
122 | <entry>8 bytes</entry> | |
e8216945 | 123 | <entry>int64_t</entry> |
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124 | </row> |
125 | ||
126 | <row> | |
127 | <entry><literal>t</literal></entry> | |
128 | <entry><constant>SD_BUS_TYPE_UINT64</constant></entry> | |
129 | <entry>unsigned integer</entry> | |
130 | <entry>8 bytes</entry> | |
e8216945 | 131 | <entry>uint64_t</entry> |
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132 | </row> |
133 | ||
134 | <row> | |
135 | <entry><literal>d</literal></entry> | |
136 | <entry><constant>SD_BUS_TYPE_DOUBLE</constant></entry> | |
137 | <entry>floating-point</entry> | |
138 | <entry>8 bytes</entry> | |
e8216945 | 139 | <entry>double</entry> |
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140 | </row> |
141 | ||
142 | <row> | |
143 | <entry><literal>s</literal></entry> | |
144 | <entry><constant>SD_BUS_TYPE_STRING</constant></entry> | |
145 | <entry>Unicode string</entry> | |
146 | <entry>variable</entry> | |
e8216945 | 147 | <entry>char[]</entry> |
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148 | </row> |
149 | ||
150 | <row> | |
151 | <entry><literal>o</literal></entry> | |
152 | <entry><constant>SD_BUS_TYPE_OBJECT_PATH</constant></entry> | |
153 | <entry>object path</entry> | |
154 | <entry>variable</entry> | |
e8216945 | 155 | <entry>char[]</entry> |
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156 | </row> |
157 | ||
158 | <row> | |
159 | <entry><literal>g</literal></entry> | |
160 | <entry><constant>SD_BUS_TYPE_SIGNATURE</constant></entry> | |
161 | <entry>signature</entry> | |
162 | <entry>variable</entry> | |
e8216945 | 163 | <entry>char[]</entry> |
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164 | </row> |
165 | ||
166 | <row> | |
167 | <entry><literal>h</literal></entry> | |
168 | <entry><constant>SD_BUS_TYPE_UNIX_FD</constant></entry> | |
169 | <entry>UNIX file descriptor</entry> | |
170 | <entry>4 bytes</entry> | |
e8216945 | 171 | <entry>int</entry> |
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172 | </row> |
173 | </tbody> | |
174 | </tgroup> | |
175 | </table> | |
176 | ||
e8216945 LP |
177 | <para>The value of the parameter is copied into a memory area held |
178 | by the message object, stays in the possession of the caller and | |
179 | may hence be freely changed after this call without affecting the | |
180 | bus message it has been added to. If <parameter>type</parameter> | |
181 | is <literal>h</literal> (UNIX file descriptor), the descriptor is | |
182 | duplicated by this call and the passed descriptor stays in | |
183 | possession of the caller.</para> | |
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184 | |
185 | <para>For types <literal>s</literal>, <literal>o</literal>, and | |
186 | <literal>g</literal>, the parameter <parameter>p</parameter> is | |
187 | interpreted as a pointer to a <constant>NUL</constant>-terminated | |
188 | character sequence. As a special case, a <constant>NULL</constant> | |
189 | pointer is interpreted as an empty string. The string should be | |
190 | valid Unicode string encoded as UTF-8. In case of the two latter | |
b8bde116 | 191 | types, the additional requirements for a D-Bus object path or |
effbc8e4 | 192 | type signature should be satisfied. Those requirements should be |
06b643e7 | 193 | verified by the recipient of the message. |
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194 | </para> |
195 | </refsect1> | |
196 | ||
197 | <refsect1> | |
198 | <title>Return Value</title> | |
199 | ||
200 | <para>On success, this call returns 0 or a positive integer. On | |
201 | failure, it returns a negative errno-style error code.</para> | |
effbc8e4 | 202 | |
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203 | <refsect2 id='errors'> |
204 | <title>Errors</title> | |
effbc8e4 | 205 | |
b1de39de | 206 | <para>Returned errors may indicate the following problems:</para> |
effbc8e4 | 207 | |
b1de39de | 208 | <variablelist> |
effbc8e4 | 209 | |
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210 | <varlistentry> |
211 | <term><constant>-EINVAL</constant></term> | |
effbc8e4 | 212 | |
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213 | <listitem><para>Specified parameter is invalid. |
214 | </para></listitem> | |
215 | </varlistentry> | |
effbc8e4 | 216 | |
b1de39de ZJS |
217 | <varlistentry> |
218 | <term><constant>-EPERM</constant></term> | |
effbc8e4 | 219 | |
b1de39de ZJS |
220 | <listitem><para>Message has been sealed. |
221 | </para></listitem> | |
222 | </varlistentry> | |
effbc8e4 | 223 | |
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224 | <varlistentry> |
225 | <term><constant>-ESTALE</constant></term> | |
effbc8e4 | 226 | |
b1de39de ZJS |
227 | <listitem><para>Message is in invalid state. |
228 | </para></listitem> | |
229 | </varlistentry> | |
effbc8e4 | 230 | |
b1de39de ZJS |
231 | <varlistentry> |
232 | <term><constant>-ENXIO</constant></term> | |
effbc8e4 | 233 | |
b1de39de ZJS |
234 | <listitem><para>Message cannot be appended to. |
235 | </para></listitem> | |
236 | </varlistentry> | |
effbc8e4 | 237 | |
b1de39de ZJS |
238 | <varlistentry> |
239 | <term><constant>-ENOMEM</constant></term> | |
effbc8e4 | 240 | |
b1de39de ZJS |
241 | <listitem><para>Memory allocation failed.</para></listitem> |
242 | </varlistentry> | |
243 | </variablelist> | |
244 | </refsect2> | |
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245 | </refsect1> |
246 | ||
7d6b2723 | 247 | <xi:include href="libsystemd-pkgconfig.xml" /> |
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248 | |
249 | <refsect1> | |
250 | <title>See Also</title> | |
251 | ||
252 | <para> | |
253 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
254 | <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
50972aac | 255 | <citerefentry><refentrytitle>sd_bus_message_read_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
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256 | <citerefentry><refentrytitle>sd_bus_message_append</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
257 | <ulink url="http://dbus.freedesktop.org/doc/dbus-specification.html">The D-Bus specification</ulink> | |
258 | </para> | |
259 | </refsect1> | |
260 | ||
261 | </refentry> |