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244 lines
9.4 KiB
XML
244 lines
9.4 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!--
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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-->
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<refentry id="sd_uid_get_state" conditional='HAVE_PAM'>
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<refentryinfo>
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<title>sd_uid_get_state</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>Lennart</firstname>
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<surname>Poettering</surname>
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<email>lennart@poettering.net</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>sd_uid_get_state</refentrytitle>
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<manvolnum>3</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>sd_uid_get_state</refname>
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<refname>sd_uid_is_on_seat</refname>
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<refname>sd_uid_get_sessions</refname>
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<refname>sd_uid_get_seats</refname>
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<refname>sd_uid_get_display</refname>
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<refpurpose>Determine login state of a specific Unix user ID</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcsynopsisinfo>#include <systemd/sd-login.h></funcsynopsisinfo>
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<funcprototype>
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<funcdef>int <function>sd_uid_get_state</function></funcdef>
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<paramdef>uid_t <parameter>uid</parameter></paramdef>
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<paramdef>char **<parameter>state</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_uid_is_on_seat</function></funcdef>
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<paramdef>uid_t <parameter>uid</parameter></paramdef>
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<paramdef>int <parameter>require_active</parameter></paramdef>
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<paramdef>const char *<parameter>seat</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_uid_get_sessions</function></funcdef>
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<paramdef>uid_t <parameter>uid</parameter></paramdef>
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<paramdef>int <parameter>require_active</parameter></paramdef>
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<paramdef>char ***<parameter>sessions</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_uid_get_seats</function></funcdef>
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<paramdef>uid_t <parameter>uid</parameter></paramdef>
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<paramdef>int <parameter>require_active</parameter></paramdef>
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<paramdef>char ***<parameter>seats</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_uid_get_display</function></funcdef>
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<paramdef>uid_t <parameter>uid</parameter></paramdef>
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<paramdef>char **<parameter>session</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para><function>sd_uid_get_state()</function> may be used to
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determine the login state of a specific Unix user identifier. The
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following states are currently known: <literal>offline</literal>
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(user not logged in at all), <literal>lingering</literal> (user
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not logged in, but some user services running),
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<literal>online</literal> (user logged in, but not active, i.e.
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has no session in the foreground), <literal>active</literal> (user
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logged in, and has at least one active session, i.e. one session
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in the foreground), <literal>closing</literal> (user not logged
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in, and not lingering, but some processes are still around). In
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the future additional states might be defined, client code should
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be written to be robust in regards to additional state strings
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being returned. The returned string needs to be freed with the
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libc
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<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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call after use.</para>
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<para><function>sd_uid_is_on_seat()</function> may be used to
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determine whether a specific user is logged in or active on a
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specific seat. Accepts a Unix user identifier and a seat
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identifier string as parameters. The
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<parameter>require_active</parameter> parameter is a boolean
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value. If non-zero (true), this function will test if the user is
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active (i.e. has a session that is in the foreground and accepting
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user input) on the specified seat, otherwise (false) only if the
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user is logged in (and possibly inactive) on the specified
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seat.</para>
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<para><function>sd_uid_get_sessions()</function> may be used to
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determine the current sessions of the specified user. Accepts a
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Unix user identifier as parameter. The
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<parameter>require_active</parameter> parameter controls whether
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the returned list shall consist of only those sessions where the
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user is currently active (> 0), where the user is currently
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online but possibly inactive (= 0), or logged in at all but
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possibly closing the session (< 0). The call returns a
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<constant>NULL</constant> terminated string array of session
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identifiers in <parameter>sessions</parameter> which needs to be
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freed by the caller with the libc
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<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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call after use, including all the strings referenced. If the
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string array parameter is passed as <constant>NULL</constant>, the
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array will not be filled in, but the return code still indicates
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the number of current sessions. Note that instead of an empty
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array <constant>NULL</constant> may be returned and should be
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considered equivalent to an empty array.</para>
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<para>Similarly, <function>sd_uid_get_seats()</function> may be
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used to determine the list of seats on which the user currently
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has sessions. Similar semantics apply, however note that the user
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may have multiple sessions on the same seat as well as sessions
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with no attached seat and hence the number of entries in the
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returned array may differ from the one returned by
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<function>sd_uid_get_sessions()</function>.</para>
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<para><function>sd_uid_get_display()</function> returns the name
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of the "primary" session of a user. If the user has graphical
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sessions, it will be the oldest graphical session. Otherwise, it
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will be the oldest open session.</para>
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</refsect1>
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<refsect1>
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<title>Return Value</title>
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<para>On success, <function>sd_uid_get_state()</function> returns
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0 or a positive integer. If the test succeeds,
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<function>sd_uid_is_on_seat()</function> returns a positive
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integer; if it fails, 0.
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<function>sd_uid_get_sessions()</function> and
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<function>sd_uid_get_seats()</function> return the number of
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entries in the returned arrays.
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<function>sd_uid_get_display()</function> returns a non-negative
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code on success. On failure, these calls return a negative
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errno-style error code.</para>
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</refsect1>
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<refsect1>
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<title>Errors</title>
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<para>Returned errors may indicate the following problems:</para>
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<variablelist>
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<varlistentry>
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<term><constant>-ENODATA</constant></term>
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<listitem><para>The given field is not specified for the described
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user.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-ENXIO</constant></term>
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<listitem><para>The specified seat is unknown.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-EINVAL</constant></term>
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<listitem><para>An input parameter was invalid (out of range,
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or NULL, where that is not accepted). This is also returned if
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the passed user ID is 0xFFFF or 0xFFFFFFFF, which are
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undefined on Linux.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-ENOMEM</constant></term>
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<listitem><para>Memory allocation failed.</para></listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Notes</title>
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<para>Functions described here are available as a shared library,
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and can be compiled and linked to using the
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<constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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entry.</para>
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</refsect1>
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<refsect1>
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<title>History</title>
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<para><function>sd_uid_get_state()</function>,
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<function>sd_uid_is_on_seat()</function>,
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<function>sd_uid_get_sessions()</function>, and
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<function>sd_uid_get_seats()</function> functions were added in
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systemd-31.</para>
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<para><function>sd_uid_get_display()</function> was added in
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systemd-213.</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<para>
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_pid_get_owner_uid</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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</para>
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</refsect1>
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</refentry>
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