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514094f9 | 1 | <?xml version='1.0'?> |
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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 | SPDX-License-Identifier: LGPL-2.1+ | |
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7 | --> |
8 | ||
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9 | <refentry id="sd_bus_is_open" |
10 | xmlns:xi="http://www.w3.org/2001/XInclude"> | |
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11 | |
12 | <refentryinfo> | |
13 | <title>sd_bus_is_open</title> | |
14 | <productname>systemd</productname> | |
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15 | </refentryinfo> |
16 | ||
17 | <refmeta> | |
18 | <refentrytitle>sd_bus_is_open</refentrytitle> | |
19 | <manvolnum>3</manvolnum> | |
20 | </refmeta> | |
21 | ||
22 | <refnamediv> | |
23 | <refname>sd_bus_is_open</refname> | |
24 | <refname>sd_bus_is_ready</refname> | |
25 | ||
26 | <refpurpose>Check whether the a bus connection is open or ready.</refpurpose> | |
27 | </refnamediv> | |
28 | ||
29 | <refsynopsisdiv> | |
30 | <funcsynopsis> | |
31 | <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> | |
32 | ||
33 | <funcprototype> | |
34 | <funcdef>int <function>sd_bus_is_open</function></funcdef> | |
35 | <paramdef>sd_bus *<parameter>bus</parameter></paramdef> | |
36 | </funcprototype> | |
37 | ||
38 | <funcprototype> | |
39 | <funcdef>int <function>sd_bus_is_ready</function></funcdef> | |
40 | <paramdef>sd_bus *<parameter>bus</parameter></paramdef> | |
41 | </funcprototype> | |
42 | ||
43 | </funcsynopsis> | |
44 | </refsynopsisdiv> | |
45 | ||
46 | <refsect1> | |
47 | <title>Description</title> | |
48 | ||
49 | <para><function>sd_bus_is_open()</function> checks whether the specified bus connection is open, i.e. in the | |
50 | process of being established, already established or in the process of being torn down. It returns zero when the | |
51 | connection has not been started yet | |
52 | (i.e. <citerefentry><refentrytitle>sd_bus_start</refentrytitle><manvolnum>3</manvolnum></citerefentry> or some | |
53 | equivalent call has not been invoked yet), or is fully terminated again (for example after | |
54 | <citerefentry><refentrytitle>sd_bus_close</refentrytitle><manvolnum>3</manvolnum></citerefentry>), it returns | |
55 | positive otherwise.</para> | |
56 | ||
57 | <para><function>sd_bus_is_ready()</function> checks whether the specified connection is fully established, | |
58 | i.e. completed the connection and authentication phases of the protocol and received the | |
59 | <function>Hello()</function> method call response, and is not in the process of being torn down again. It returns | |
60 | zero outside of this state, and positive otherwise. Effectively, this function returns positive while regular | |
61 | messages can be sent or received on the connection.</para> | |
62 | ||
63 | <para>To be notified when the connection is fully established, use | |
64 | <citerefentry><refentrytitle>sd_bus_set_connected_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry> and | |
65 | install a match for the <function>Connected()</function> signal on the | |
66 | <literal>org.freedesktop.DBus.Local</literal> interface. To be notified when the connection is torn down again, | |
67 | install a match for the <function>Disconnected()</function> signal on the | |
68 | <literal>org.freedesktop.DBus.Local</literal> interface.</para> | |
69 | </refsect1> | |
70 | ||
71 | <refsect1> | |
72 | <title>Return Value</title> | |
73 | ||
74 | <para>On success, these functions return 0 or a positive integer. On failure, they return a negative errno-style | |
75 | error code.</para> | |
76 | </refsect1> | |
77 | ||
78 | <refsect1> | |
79 | <title>Errors</title> | |
80 | ||
81 | <para>Returned errors may indicate the following problems:</para> | |
82 | ||
83 | <variablelist> | |
84 | <varlistentry> | |
85 | <term><constant>-ECHILD</constant></term> | |
86 | ||
87 | <listitem><para>The bus connection has been created in a different process.</para></listitem> | |
88 | </varlistentry> | |
89 | </variablelist> | |
90 | </refsect1> | |
91 | ||
7647c01d | 92 | <xi:include href="libsystemd-pkgconfig.xml" /> |
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93 | |
94 | <refsect1> | |
95 | <title>See Also</title> | |
96 | ||
97 | <para> | |
98 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
99 | <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
100 | <citerefentry><refentrytitle>sd_bus_start</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
101 | <citerefentry><refentrytitle>sd_bus_close</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
102 | <citerefentry><refentrytitle>sd_bus_set_connected_signal</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
103 | </para> | |
104 | </refsect1> | |
105 | ||
106 | </refentry> |