<?xml version='1.0'?> <!--*-nxml-*--> <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> <!-- This file is part of systemd. Copyright 2010 Lennart Poettering systemd is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. --> <refentry id="sd_get_seats" conditional='HAVE_PAM'> <refentryinfo> <title>sd_get_seats</title> <productname>systemd</productname> <authorgroup> <author> <contrib>Developer</contrib> <firstname>Lennart</firstname> <surname>Poettering</surname> <email>lennart@poettering.net</email> </author> </authorgroup> </refentryinfo> <refmeta> <refentrytitle>sd_get_seats</refentrytitle> <manvolnum>3</manvolnum> </refmeta> <refnamediv> <refname>sd_get_seats</refname> <refname>sd_get_sessions</refname> <refname>sd_get_uids</refname> <refname>sd_get_machine_names</refname> <refpurpose>Determine available seats, sessions, logged in users and virtual machines/containers</refpurpose> </refnamediv> <refsynopsisdiv> <funcsynopsis> <funcsynopsisinfo>#include <systemd/sd-login.h></funcsynopsisinfo> <funcprototype> <funcdef>int <function>sd_get_seats</function></funcdef> <paramdef>char ***<parameter>seats</parameter></paramdef> </funcprototype> <funcprototype> <funcdef>int <function>sd_get_sessions</function></funcdef> <paramdef>char ***<parameter>sessions</parameter></paramdef> </funcprototype> <funcprototype> <funcdef>int <function>sd_get_uids</function></funcdef> <paramdef>uid_t **<parameter>users</parameter></paramdef> </funcprototype> <funcprototype> <funcdef>int <function>sd_get_machine_names</function></funcdef> <paramdef>char ***<parameter>machines</parameter></paramdef> </funcprototype> </funcsynopsis> </refsynopsisdiv> <refsect1> <title>Description</title> <para><function>sd_get_seats()</function> may be used to determine all currently available local seats. Returns a <constant>NULL</constant> terminated array of seat identifiers. The returned array and all strings it references need to be freed with the libc <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry> call after use. Note that instead of an empty array <constant>NULL</constant> may be returned and should be considered equivalent to an empty array.</para> <para>Similarly, <function>sd_get_sessions()</function> may be used to determine all current login sessions.</para> <para>Similarly, <function>sd_get_uids()</function> may be used to determine all Unix users who currently have login sessions.</para> <para>Similarly, <function>sd_get_machine_names()</function> may be used to determine all current virtual machines and containers on the system.</para> <para>Note that the returned lists are not sorted and in an undefined order.</para> </refsect1> <refsect1> <title>Return Value</title> <para>On success, <function>sd_get_seats()</function>, <function>sd_get_sessions()</function>, <function>sd_get_uids()</function> and <function>sd_get_machine_names()</function> return the number of entries in the arrays. On failure, these calls return a negative errno-style error code.</para> </refsect1> <refsect1> <title>Notes</title> <para>The <function>sd_get_seats()</function>, <function>sd_get_sessions()</function>, <function>sd_get_uids()</function> and <function>sd_get_machine_names()</function> interfaces are available as a shared library, which can be compiled and linked to with the <constant>libsystemd</constant> <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> file.</para> </refsect1> <refsect1> <title>See Also</title> <para> <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>3</manvolnum></citerefentry>, <citerefentry><refentrytitle>sd_session_get_seat</refentrytitle><manvolnum>3</manvolnum></citerefentry> </para> </refsect1> </refentry>