man-pages/man3/sd_get_seats.3.html
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<H1>SD_GET_SEATS</H1>
Section: sd_get_seats (3)<BR>Updated: <BR><A HREF="#index">Index</A>
<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
<A NAME="lbAB">&nbsp;</A>
<H2>NAME</H2>
sd_get_seats, sd_get_sessions, sd_get_uids, sd_get_machine_names - Determine available seats, sessions, logged in users and virtual machines/containers
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>
<P>
<B>
</B><PRE>
#include &lt;<A HREF="file:///usr/include/systemd/sd-login.h">systemd/sd-login.h</A>&gt;
</PRE>
<DL COMPACT>
<DT id="1">
<B>int sd_get_seats(char&nbsp;***</B><I>seats</I><B>);</B>
<DT id="2">
<B>int sd_get_sessions(char&nbsp;***</B><I>sessions</I><B>);</B>
<DT id="3">
<B>int sd_get_uids(uid_t&nbsp;**</B><I>users</I><B>);</B>
<DT id="4">
<B>int sd_get_machine_names(char&nbsp;***</B><I>machines</I><B>);</B>
</DL>
<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>
<P>
<B>sd_get_seats()</B>
<DD>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
<B>NULL</B>-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
<B><A HREF="/cgi-bin/man/man2html?3+free">free</A></B>(3)
call after use. Note that instead of an empty array
<B>NULL</B>
may be returned and should be considered equivalent to an empty array.
<P>
Similarly,
<B>sd_get_sessions()</B>
may be used to determine all current login sessions.
<P>
Similarly,
<B>sd_get_uids()</B>
may be used to determine all Unix users who currently have login sessions.
<P>
Similarly,
<B>sd_get_machine_names()</B>
may be used to determine all current virtual machines and containers on the system.
<P>
Note that the returned lists are not sorted and in an undefined order.
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<H2>RETURN VALUE</H2>
<P>
On success,
<B>sd_get_seats()</B>,
<B>sd_get_sessions()</B>,
<B>sd_get_uids()</B>
and
<B>sd_get_machine_names()</B>
return the number of entries in the arrays. On failure, these calls return a negative errno-style error code.
<A NAME="lbAF">&nbsp;</A>
<H3>Errors</H3>
<P>
Returned errors may indicate the following problems:
<P>
<B>-ENOMEM</B>
<DL COMPACT><DT id="5"><DD>
Memory allocation failed.
</DL>
<A NAME="lbAG">&nbsp;</A>
<H2>NOTES</H2>
<P>
These APIs are implemented as a shared library, which can be compiled and linked to with the
<B>libsystemd</B>&nbsp;<B><A HREF="/cgi-bin/man/man2html?1+pkg-config">pkg-config</A></B>(1)
file.
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<H2>SEE ALSO</H2>
<P>
<B><A HREF="/cgi-bin/man/man2html?1+systemd">systemd</A></B>(1),
<B><A HREF="/cgi-bin/man/man2html?3+sd-login">sd-login</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+sd_session_get_seat">sd_session_get_seat</A></B>(3)
<P>
<HR>
<A NAME="index">&nbsp;</A><H2>Index</H2>
<DL>
<DT id="6"><A HREF="#lbAB">NAME</A><DD>
<DT id="7"><A HREF="#lbAC">SYNOPSIS</A><DD>
<DT id="8"><A HREF="#lbAD">DESCRIPTION</A><DD>
<DT id="9"><A HREF="#lbAE">RETURN VALUE</A><DD>
<DL>
<DT id="10"><A HREF="#lbAF">Errors</A><DD>
</DL>
<DT id="11"><A HREF="#lbAG">NOTES</A><DD>
<DT id="12"><A HREF="#lbAH">SEE ALSO</A><DD>
</DL>
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Time: 00:05:55 GMT, March 31, 2021
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