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">
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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
  93                 <para>Note that the returned lists are not sorted and in an undefined order.</para>
  94         </refsect1>
  95
  96         <refsect1>
  97                 <title>Return Value</title>
  98
  99                 <para>On success <function>sd_get_seats()</function>,
 100                 <function>sd_get_sessions()</function> and
 101                 <function>sd_get_uids()</function> return the number
 102                 of entries in the arrays. On failure, these calls
 103                 return a negative errno-style error code.</para>
 104         </refsect1>
 105
 106         <refsect1>
 107                 <title>Notes</title>
 108
 109                 <para>The <function>sd_get_seats()</function>,
 110                 <function>sd_get_sessions()</function> and
 111                 <function>sd_get_uids()</function> interfaces
 112                 are available as shared library, which can be compiled
 113                 and linked to with the
 114                 <literal>libsystemd-login</literal>
 115                 <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 116                 file.</para>
 117         </refsect1>
 118
 119         <refsect1>
 120                 <title>See Also</title>
 121
 122                 <para>
 123                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 124                         <citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 125                         <citerefentry><refentrytitle>sd_session_get_seat</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 126                 </para>
 127         </refsect1>
 128
 129 </refentry>