Systemd/man/sd_get_seats.xml
Lennart Poettering 818bf54632 tree-wide: drop 'This file is part of systemd' blurb
This part of the copyright blurb stems from the GPL use recommendations:

https://www.gnu.org/licenses/gpl-howto.en.html

The concept appears to originate in times where version control was per
file, instead of per tree, and was a way to glue the files together.
Ultimately, we nowadays don't live in that world anymore, and this
information is entirely useless anyway, as people are very welcome to
copy these files into any projects they like, and they shouldn't have to
change bits that are part of our copyright header for that.

hence, let's just get rid of this old cruft, and shorten our codebase a
bit.
2018-06-14 10:20:20 +02:00

136 lines
4.3 KiB
XML

<?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">
<!--
SPDX-License-Identifier: LGPL-2.1+
Copyright 2010 Lennart Poettering
-->
<refentry id="sd_get_seats" conditional='HAVE_PAM'
xmlns:xi="http://www.w3.org/2001/XInclude">
<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 the number of seat
identifiers and if the input pointer is non-NULL, a
<constant>NULL</constant>-terminated array of seat identifiers
is stored at the address.
The returned array and all strings it references need to be freed
with the libc
<citerefentry project='man-pages'><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>Errors</title>
<para>Returned errors may indicate the following problems:</para>
<variablelist>
<varlistentry>
<term><constant>-ENOMEM</constant></term>
<listitem><para>Memory allocation failed.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<xi:include href="libsystemd-pkgconfig.xml" />
<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>