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" conditional='HAVE_PAM'>
  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                 <refname>sd_get_machine_names</refname>
  50                 <refpurpose>Determine available seats, sessions, logged in users and virtual machines/containers</refpurpose>
  51         </refnamediv>
  52
  53         <refsynopsisdiv>
  54                 <funcsynopsis>
  55                         <funcsynopsisinfo>#include &lt;systemd/sd-login.h&gt;</funcsynopsisinfo>
  56
  57                         <funcprototype>
  58                                 <funcdef>int <function>sd_get_seats</function></funcdef>
  59                                 <paramdef>char ***<parameter>seats</parameter></paramdef>
  60                         </funcprototype>
  61
  62                         <funcprototype>
  63                                 <funcdef>int <function>sd_get_sessions</function></funcdef>
  64                                 <paramdef>char ***<parameter>sessions</parameter></paramdef>
  65                         </funcprototype>
  66
  67                         <funcprototype>
  68                                 <funcdef>int <function>sd_get_uids</function></funcdef>
  69                                 <paramdef>uid_t **<parameter>users</parameter></paramdef>
  70                         </funcprototype>
  71
  72                         <funcprototype>
  73                                 <funcdef>int <function>sd_get_machine_names</function></funcdef>
  74                                 <paramdef>char ***<parameter>machines</parameter></paramdef>
  75                         </funcprototype>
  76
  77                 </funcsynopsis>
  78         </refsynopsisdiv>
  79
  80         <refsect1>
  81                 <title>Description</title>
  82
  83                 <para><function>sd_get_seats()</function> may be used
  84                 to determine all currently available local
  85                 seats. Returns a <constant>NULL</constant> terminated array of seat
  86                 identifiers. The returned array and all strings it
  87                 references need to be freed with the libc
  88                 <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
  89                 call after use. Note that instead of an empty array
  90                 <constant>NULL</constant> may be returned and should be considered
  91                 equivalent to an empty array.</para>
  92
  93                 <para>Similarly, <function>sd_get_sessions()</function> may
  94                 be used to determine all current login sessions.</para>
  95
  96                 <para>Similarly, <function>sd_get_uids()</function> may
  97                 be used to determine all Unix users who currently have login sessions.</para>
  98
  99                 <para>Similarly,
 100                 <function>sd_get_machine_names()</function> may be
 101                 used to determine all current virtual machines and
 102                 containers on the system.</para>
 103
 104                 <para>Note that the returned lists are not sorted and in an undefined order.</para>
 105         </refsect1>
 106
 107         <refsect1>
 108                 <title>Return Value</title>
 109
 110                 <para>On success, <function>sd_get_seats()</function>,
 111                 <function>sd_get_sessions()</function>,
 112                 <function>sd_get_uids()</function> and
 113                 <function>sd_get_machine_names()</function> return the
 114                 number of entries in the arrays. On failure, these
 115                 calls return a negative errno-style error code.</para>
 116         </refsect1>
 117
 118         <refsect1>
 119                 <title>Notes</title>
 120
 121                 <para>The <function>sd_get_seats()</function>,
 122                 <function>sd_get_sessions()</function>,
 123                 <function>sd_get_uids()</function> and
 124                 <function>sd_get_machine_names()</function> interfaces
 125                 are available as a shared library, which can be compiled
 126                 and linked to with the
 127                 <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 128                 file.</para>
 129         </refsect1>
 130
 131         <refsect1>
 132                 <title>See Also</title>
 133
 134                 <para>
 135                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 136                         <citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 137                         <citerefentry><refentrytitle>sd_session_get_seat</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 138                 </para>
 139         </refsect1>
 140
 141 </refentry>