1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
|
<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
This file is part of systemd.
Copyright 2013 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refentry id="sd_bus_request_name">
<refentryinfo>
<title>sd_bus_request_name</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Lennart</firstname>
<surname>Poettering</surname>
<email>lennart@poettering.net</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>sd_bus_request_name</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_bus_request_name</refname>
<refname>sd_bus_release_name</refname>
<refpurpose>Request or release a well-known name on a bus</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_bus_request_name</function></funcdef>
<paramdef>sd_bus* <parameter>bus</parameter></paramdef>
<paramdef>const char *<parameter>name</parameter></paramdef>
<paramdef>uint64_t <parameter>flags</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_bus_release_name</function></funcdef>
<paramdef>sd_bus* <parameter>bus</parameter></paramdef>
<paramdef>const char *<parameter>name</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><function>sd_bus_request_name()</function> requests
a well-known name on a bus. It takes a bus connection,
a valid bus name and a flags parameter. The flags
parameter is a combination of the following
flags:</para>
<variablelist>
<varlistentry>
<term><varname>SD_BUS_NAME_ALLOW_REPLACEMENT</varname></term>
<listitem><para>After acquiring the
name successuflly, permit other peers
to take over the name when they try to
acquire it with the
<varname>SD_BUS_NAME_REPLACE_EXISTING</varname>
flag set. If
<varname>SD_BUS_NAME_ALLOW_REPLACEMENT</varname>
is not set on the original request
such a request by other peers will be
denied.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>SD_BUS_NAME_REPLACE_EXISTING</varname></term>
<listitem><para>Take over a the name
if it is already acquired by a another
peer, and that other peer permitted
taking it over by setting
<varname>SD_BUS_NAME_ALLOW_REPLACEMENT</varname>
while acquiring it.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>SD_BUS_NAME_QUEUE</varname></term>
<listitem><para>Queue name
acquisition when the name is already
taken.</para></listitem>
</varlistentry>
</variablelist>
<para><function>sd_bus_release_name()</function> releases
an acquired well-known name. It takes a bus connection
and a valid bus name as parameters.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>On success, these calls return 0 or a positive
integer. On failure, these calls return a negative
errno-style error code.</para>
<para>If <varname>SD_BUS_NAME_QUEUE</varname> is
specified <function>sd_bus_request_name()</function>
will return 0 when the name is already taken by
another peer and the client has been added to the
queue for the name. In that case the caller can
subscribe to <literal>NameOwnerChanged</literal>
signals to be notified when the name is successfully
acquired. <function>sd_bus_request_name()</function>
returns > 0 when the name has immediately been
acquired successfully.</para>
</refsect1>
<refsect1>
<title>Errors</title>
<para>Returned errors may indicate the following problems:</para>
<variablelist>
<varlistentry>
<term><varname>-EALREADY</varname></term>
<listitem><para>The caller already is
the owner of the specified
name.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>-EEXIST</varname></term>
<listitem><para>The name has already
been acquired by a different peer, and
SD_BUS_NAME_REPLACE_EXISTING was not
specified or the other peer did not
specify SD_BUS_NAME_ALLOW_REPLACEMENT
while acquiring the
name.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>-ESRCH</varname></term>
<listitem><para>It was attemted to
release a name that is currently not
registered on the
bus.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>-EADDRINUSE</varname></term>
<listitem><para>It was attemted to
release a name that is owned by a
different peer on the
bus.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>-EINVAL</varname></term>
<listitem><para>A specified parameter
is invalid.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>-ENOTCONN</varname></term>
<listitem><para>The bus connection has
been disconnected.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>-ECHILD</varname></term>
<listitem><para>The bus connection has
been created in a different process
than the current.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Notes</title>
<para>The <function>sd_bus_acquire_name()</function>
and <function>sd_bus_release_name()</function>
interfaces are available as shared library, which can
be compiled and linked to with the
<constant>libsystemd-bus</constant> <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
file.</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_bus_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
|
