man/sd_session_is_active.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_session_is_active">
  25
  26         <refentryinfo>
  27                 <title>sd_session_is_active</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_session_is_active</refentrytitle>
  42                 <manvolnum>3</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>sd_session_is_active</refname>
  47                 <refname>sd_session_get_uid</refname>
  48                 <refname>sd_session_get_seat</refname>
  49                 <refpurpose>Determine state of a specific session</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_session_is_active</function></funcdef>
  58                                 <paramdef>const char* <parameter>session</parameter></paramdef>
  59                         </funcprototype>
  60
  61                         <funcprototype>
  62                                 <funcdef>int <function>sd_session_get_uid</function></funcdef>
  63                                 <paramdef>const char* <parameter>session</parameter></paramdef>
  64                                 <paramdef>uid_t* <parameter>uid</parameter></paramdef>
  65                         </funcprototype>
  66
  67                         <funcprototype>
  68                                 <funcdef>int <function>sd_session_get_seat</function></funcdef>
  69                                 <paramdef>const char* <parameter>session</parameter></paramdef>
  70                                 <paramdef>char** <parameter>seat</parameter></paramdef>
  71                         </funcprototype>
  72                 </funcsynopsis>
  73         </refsynopsisdiv>
  74
  75         <refsect1>
  76                 <title>Description</title>
  77
  78                 <para><function>sd_session_is_active()</function> may
  79                 be used to determine whether the session identified by
  80                 the specified session identifier is currently active
  81                 (i.e. currently in the foreground and available for
  82                 user input) or not.</para>
  83
  84                 <para><function>sd_session_get_uid()</function> may be
  85                 used to determine the user identifier of the Unix user the session
  86                 identified by the specified session identifier belongs
  87                 to.</para>
  88
  89                 <para><function>sd_session_get_seat()</function> may
  90                 be used to determine the seat identifier of the seat
  91                 the session identified by the specified session
  92                 identifier belongs to. Note that not all sessions are
  93                 attached to a seat, this call will fail for them. The
  94                 returned string needs to be freed with the libc
  95                 <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
  96                 call after use.</para>
  97         </refsect1>
  98
  99         <refsect1>
 100                 <title>Return Value</title>
 101
 102                 <para>If the test succeeds
 103                 <function>sd_session_is_active()</function> returns a
 104                 positive integer, if it fails 0.  On success
 105                 <function>sd_session_get_uid()</function> and
 106                 <function>sd_session_get_seat()</function> return 0 or
 107                 a positive integer. On failure, these calls return a
 108                 negative errno-style error code.</para>
 109         </refsect1>
 110
 111         <refsect1>
 112                 <title>Notes</title>
 113
 114                 <para>The <function>sd_session_is_active()</function>,
 115                 <function>sd_session_get_uid()</function>, and
 116                 <function>sd_session_get_seat()</function> interfaces
 117                 are available as shared library, which can be compiled
 118                 and linked to with the
 119                 <literal>libsystemd-login</literal>
 120                 <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 121                 file.</para>
 122         </refsect1>
 123
 124         <refsect1>
 125                 <title>See Also</title>
 126
 127                 <para>
 128                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 129                         <citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 130                         <citerefentry><refentrytitle>sd_pid_get_session</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 131                 </para>
 132         </refsect1>
 133
 134 </refentry>