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1 | <?xml version='1.0'?> <!--*-nxml-*--> |
2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" | |
e735f4d4 | 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
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4 | |
5 | <!-- | |
6 | This file is part of systemd. | |
7 | ||
8 | Copyright 2013 Lennart Poettering | |
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_request_name" conditional="ENABLE_KDBUS"> | |
25 | ||
e735f4d4 MP |
26 | <refentryinfo> |
27 | <title>sd_bus_request_name</title> | |
28 | <productname>systemd</productname> | |
29 | ||
30 | <authorgroup> | |
31 | <author> | |
32 | <contrib>Developer</contrib> | |
33 | <firstname>Lennart</firstname> | |
34 | <surname>Poettering</surname> | |
35 | <email>lennart@poettering.net</email> | |
36 | </author> | |
37 | </authorgroup> | |
38 | </refentryinfo> | |
39 | ||
40 | <refmeta> | |
41 | <refentrytitle>sd_bus_request_name</refentrytitle> | |
42 | <manvolnum>3</manvolnum> | |
43 | </refmeta> | |
44 | ||
45 | <refnamediv> | |
46 | <refname>sd_bus_request_name</refname> | |
47 | <refname>sd_bus_release_name</refname> | |
48 | <refpurpose>Request or release a well-known name on a bus</refpurpose> | |
49 | </refnamediv> | |
50 | ||
51 | <refsynopsisdiv> | |
52 | <funcsynopsis> | |
53 | <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> | |
54 | ||
55 | <funcprototype> | |
56 | <funcdef>int <function>sd_bus_request_name</function></funcdef> | |
57 | <paramdef>sd_bus *<parameter>bus</parameter></paramdef> | |
58 | <paramdef>const char *<parameter>name</parameter></paramdef> | |
59 | <paramdef>uint64_t <parameter>flags</parameter></paramdef> | |
60 | </funcprototype> | |
61 | ||
62 | <funcprototype> | |
63 | <funcdef>int <function>sd_bus_release_name</function></funcdef> | |
64 | <paramdef>sd_bus *<parameter>bus</parameter></paramdef> | |
65 | <paramdef>const char *<parameter>name</parameter></paramdef> | |
66 | </funcprototype> | |
67 | </funcsynopsis> | |
68 | </refsynopsisdiv> | |
69 | ||
70 | <refsect1> | |
71 | <title>Description</title> | |
72 | ||
73 | <para><function>sd_bus_request_name()</function> requests a | |
74 | well-known name on a bus. It takes a bus connection, a valid bus | |
75 | name and a flags parameter. The flags parameter is a combination | |
76 | of the following flags:</para> | |
77 | ||
78 | <variablelist> | |
79 | <varlistentry> | |
80 | <term><varname>SD_BUS_NAME_ALLOW_REPLACEMENT</varname></term> | |
81 | ||
82 | <listitem><para>After acquiring the name successfully, permit | |
83 | other peers to take over the name when they try to acquire it | |
84 | with the <varname>SD_BUS_NAME_REPLACE_EXISTING</varname> flag | |
85 | set. If <varname>SD_BUS_NAME_ALLOW_REPLACEMENT</varname> is | |
86 | not set on the original request, such a request by other peers | |
87 | will be denied.</para></listitem> | |
88 | </varlistentry> | |
89 | ||
90 | <varlistentry> | |
91 | <term><varname>SD_BUS_NAME_REPLACE_EXISTING</varname></term> | |
92 | ||
93 | <listitem><para>Take over the name if it is already acquired | |
94 | by another peer, and that other peer has permitted takeover by | |
95 | setting <varname>SD_BUS_NAME_ALLOW_REPLACEMENT</varname> while | |
96 | acquiring it.</para></listitem> | |
97 | </varlistentry> | |
98 | ||
99 | <varlistentry> | |
100 | <term><varname>SD_BUS_NAME_QUEUE</varname></term> | |
101 | ||
102 | <listitem><para>Queue the acquisition of the name when the | |
103 | name is already taken.</para></listitem> | |
104 | </varlistentry> | |
105 | </variablelist> | |
106 | ||
107 | <para><function>sd_bus_release_name()</function> releases an | |
108 | acquired well-known name. It takes a bus connection and a valid | |
109 | bus name as parameters.</para> | |
110 | </refsect1> | |
111 | ||
112 | <refsect1> | |
113 | <title>Return Value</title> | |
114 | ||
115 | <para>On success, these calls return 0 or a positive integer. On | |
116 | failure, these calls return a negative errno-style error | |
117 | code.</para> | |
118 | ||
119 | <para>If <varname>SD_BUS_NAME_QUEUE</varname> is specified, | |
120 | <function>sd_bus_request_name()</function> will return 0 when the | |
121 | name is already taken by another peer and the client has been | |
122 | added to the queue for the name. In that case, the caller can | |
123 | subscribe to <literal>NameOwnerChanged</literal> signals to be | |
124 | notified when the name is successfully acquired. | |
125 | <function>sd_bus_request_name()</function> returns > 0 when the | |
126 | name has immediately been acquired successfully.</para> | |
127 | </refsect1> | |
128 | ||
129 | <refsect1> | |
130 | <title>Errors</title> | |
131 | ||
132 | <para>Returned errors may indicate the following problems:</para> | |
133 | ||
134 | <variablelist> | |
135 | <varlistentry> | |
136 | <term><constant>-EALREADY</constant></term> | |
137 | ||
138 | <listitem><para>The caller already is the owner of the | |
139 | specified name.</para></listitem> | |
140 | </varlistentry> | |
141 | ||
142 | <varlistentry> | |
143 | <term><constant>-EEXIST</constant></term> | |
144 | ||
145 | <listitem><para>The name has already been acquired by a | |
146 | different peer, and SD_BUS_NAME_REPLACE_EXISTING was not | |
147 | specified or the other peer did not specify | |
148 | SD_BUS_NAME_ALLOW_REPLACEMENT while acquiring the | |
149 | name.</para></listitem> | |
150 | </varlistentry> | |
151 | ||
152 | <varlistentry> | |
153 | <term><constant>-ESRCH</constant></term> | |
154 | ||
155 | <listitem><para>It was attempted to release a name that is | |
156 | currently not registered on the bus.</para></listitem> | |
157 | </varlistentry> | |
158 | ||
159 | <varlistentry> | |
160 | <term><constant>-EADDRINUSE</constant></term> | |
161 | ||
162 | <listitem><para>It was attempted to release a name that is | |
163 | owned by a different peer on the bus.</para></listitem> | |
164 | </varlistentry> | |
165 | ||
166 | <varlistentry> | |
167 | <term><constant>-EINVAL</constant></term> | |
168 | ||
169 | <listitem><para>A specified parameter is | |
170 | invalid.</para></listitem> | |
171 | </varlistentry> | |
172 | ||
173 | <varlistentry> | |
174 | <term><constant>-ENOTCONN</constant></term> | |
175 | ||
176 | <listitem><para>The bus connection has been | |
177 | disconnected.</para></listitem> | |
178 | </varlistentry> | |
179 | ||
180 | <varlistentry> | |
181 | <term><constant>-ECHILD</constant></term> | |
182 | ||
183 | <listitem><para>The bus connection has been created in a | |
184 | different process than the current one.</para></listitem> | |
185 | </varlistentry> | |
186 | </variablelist> | |
187 | </refsect1> | |
188 | ||
189 | <refsect1> | |
190 | <title>Notes</title> | |
191 | ||
192 | <para>The <function>sd_bus_acquire_name()</function> and | |
193 | <function>sd_bus_release_name()</function> interfaces are | |
194 | available as a shared library, which can be compiled and linked to | |
195 | with the | |
196 | <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
197 | file.</para> | |
198 | </refsect1> | |
199 | ||
200 | <refsect1> | |
201 | <title>See Also</title> | |
202 | ||
203 | <para> | |
204 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
205 | <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
206 | <citerefentry><refentrytitle>sd_bus_new</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
207 | </para> | |
208 | </refsect1> | |
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209 | |
210 | </refentry> |