man/sd_get_seats.xml

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  11   Copyright 2010 Lennart Poettering
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  26
  27 <refentry id="sd_get_seats" conditional='HAVE_PAM'>
  28
  29   <refentryinfo>
  30     <title>sd_get_seats</title>
  31     <productname>systemd</productname>
  32
  33     <authorgroup>
  34       <author>
  35         <contrib>Developer</contrib>
  36         <firstname>Lennart</firstname>
  37         <surname>Poettering</surname>
  38         <email>lennart@poettering.net</email>
  39       </author>
  40     </authorgroup>
  41   </refentryinfo>
  42
  43   <refmeta>
  44     <refentrytitle>sd_get_seats</refentrytitle>
  45     <manvolnum>3</manvolnum>
  46   </refmeta>
  47
  48   <refnamediv>
  49     <refname>sd_get_seats</refname>
  50     <refname>sd_get_sessions</refname>
  51     <refname>sd_get_uids</refname>
  52     <refname>sd_get_machine_names</refname>
  53     <refpurpose>Determine available seats, sessions, logged in users and virtual machines/containers</refpurpose>
  54   </refnamediv>
  55
  56   <refsynopsisdiv>
  57     <funcsynopsis>
  58       <funcsynopsisinfo>#include &lt;systemd/sd-login.h&gt;</funcsynopsisinfo>
  59
  60       <funcprototype>
  61         <funcdef>int <function>sd_get_seats</function></funcdef>
  62         <paramdef>char ***<parameter>seats</parameter></paramdef>
  63       </funcprototype>
  64
  65       <funcprototype>
  66         <funcdef>int <function>sd_get_sessions</function></funcdef>
  67         <paramdef>char ***<parameter>sessions</parameter></paramdef>
  68       </funcprototype>
  69
  70       <funcprototype>
  71         <funcdef>int <function>sd_get_uids</function></funcdef>
  72         <paramdef>uid_t **<parameter>users</parameter></paramdef>
  73       </funcprototype>
  74
  75       <funcprototype>
  76         <funcdef>int <function>sd_get_machine_names</function></funcdef>
  77         <paramdef>char ***<parameter>machines</parameter></paramdef>
  78       </funcprototype>
  79
  80     </funcsynopsis>
  81   </refsynopsisdiv>
  82
  83   <refsect1>
  84     <title>Description</title>
  85
  86     <para><function>sd_get_seats()</function> may be used to determine
  87     all currently available local seats. Returns a
  88     <constant>NULL</constant> terminated array of seat identifiers.
  89     The returned array and all strings it references need to be freed
  90     with the libc
  91     <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
  92     call after use. Note that instead of an empty array
  93     <constant>NULL</constant> may be returned and should be considered
  94     equivalent to an empty array.</para>
  95
  96     <para>Similarly, <function>sd_get_sessions()</function> may be
  97     used to determine all current login sessions.</para>
  98
  99     <para>Similarly, <function>sd_get_uids()</function> may be used to
 100     determine all Unix users who currently have login sessions.</para>
 101
 102     <para>Similarly, <function>sd_get_machine_names()</function> may
 103     be used to determine all current virtual machines and containers
 104     on the system.</para>
 105
 106     <para>Note that the returned lists are not sorted and in an
 107     undefined order.</para>
 108   </refsect1>
 109
 110   <refsect1>
 111     <title>Return Value</title>
 112
 113     <para>On success, <function>sd_get_seats()</function>,
 114     <function>sd_get_sessions()</function>,
 115     <function>sd_get_uids()</function> and
 116     <function>sd_get_machine_names()</function> return the number of
 117     entries in the arrays. On failure, these calls return a negative
 118     errno-style error code.</para>
 119   </refsect1>
 120
 121   <refsect1>
 122     <title>Notes</title>
 123
 124     <para>The <function>sd_get_seats()</function>,
 125     <function>sd_get_sessions()</function>,
 126     <function>sd_get_uids()</function> and
 127     <function>sd_get_machine_names()</function> interfaces are
 128     available as a shared library, which can be compiled and linked to
 129     with the
 130     <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 131     file.</para>
 132   </refsect1>
 133
 134   <refsect1>
 135     <title>See Also</title>
 136
 137     <para>
 138       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 139       <citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 140       <citerefentry><refentrytitle>sd_session_get_seat</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 141     </para>
 142   </refsect1>
 143
 144 </refentry>