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[elogind.git] / man / sd_get_seats.xml
1 <?xml version='1.0'?> <!--*-nxml-*-->
2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
4
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8   Copyright 2010 Lennart Poettering
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23
24 <refentry id="sd_get_seats">
25
26         <refentryinfo>
27                 <title>sd_get_seats</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_get_seats</refentrytitle>
42                 <manvolnum>3</manvolnum>
43         </refmeta>
44
45         <refnamediv>
46                 <refname>sd_get_seats</refname>
47                 <refname>sd_get_sessions</refname>
48                 <refname>sd_get_uids</refname>
49                 <refpurpose>Determine available seats, sessions and logged in users</refpurpose>
50         </refnamediv>
51
52         <refsynopsisdiv>
53                 <funcsynopsis>
54                         <funcsynopsisinfo>#include &lt;systemd/sd-login.h&gt;</funcsynopsisinfo>
55
56                         <funcprototype>
57                                 <funcdef>int <function>sd_get_seats</function></funcdef>
58                                 <paramdef>char*** <parameter>seats</parameter></paramdef>
59                         </funcprototype>
60
61                         <funcprototype>
62                                 <funcdef>int <function>sd_get_sessions</function></funcdef>
63                                 <paramdef>char*** <parameter>sessions</parameter></paramdef>
64                         </funcprototype>
65
66                         <funcprototype>
67                                 <funcdef>int <function>sd_get_uids</function></funcdef>
68                                 <paramdef>char*** <parameter>sessions</parameter></paramdef>
69                         </funcprototype>
70
71                 </funcsynopsis>
72         </refsynopsisdiv>
73
74         <refsect1>
75                 <title>Description</title>
76
77                 <para><function>sd_get_seats()</function> may be used
78                 to determine all currently available local
79                 seats. Returns a NULL terminated array of seat
80                 identifiers. The returned array and all strings it
81                 references need to be freed with the libc
82                 <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
83                 call after use. Note that instead of an empty array
84                 NULL may be returned and should be considered
85                 equivalent to an empty array.</para>
86
87                 <para>Similar, <function>sd_get_sessions()</function> may
88                 be used to determine all current login sessions.</para>
89
90                 <para>Similar, <function>sd_get_uids()</function> may
91                 be used to determine all Unix users who currently have login sessions.</para>
92         </refsect1>
93
94         <refsect1>
95                 <title>Return Value</title>
96
97                 <para>On success <function>sd_get_seats()</function>,
98                 <function>sd_get_sessions()</function> and
99                 <function>sd_get_uids()</function> return the number
100                 of entries in the arrays. On failure, these calls
101                 return a negative errno-style error code.</para>
102         </refsect1>
103
104         <refsect1>
105                 <title>Notes</title>
106
107                 <para>The <function>sd_get_seats()</function>,
108                 <function>sd_get_sessions()</function> and
109                 <function>sd_get_uids()</function> interfaces
110                 are available as shared library, which can be compiled
111                 and linked to with the
112                 <literal>libsystemd-login</literal>
113                 <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
114                 file.</para>
115         </refsect1>
116
117         <refsect1>
118                 <title>See Also</title>
119
120                 <para>
121                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
122                         <citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
123                         <citerefentry><refentrytitle>sd_session_get_seat</refentrytitle><manvolnum>3</manvolnum></citerefentry>
124                 </para>
125         </refsect1>
126
127 </refentry>