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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"

"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

<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 &lt;systemd/sd-login.h&gt;</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>Similar, <function>sd_get_sessions()</function> may

be used to determine all current login sessions.</para>

<para>Similar, <function>sd_get_uids()</function> may

be used to determine all Unix users who currently have login sessions.</para>

<para>Similar,

<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 shared library, which can be compiled

and linked to with the

<constant>libsystemd-login</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>