1 <html><head><meta http-equiv=
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</a><span style=
"float:right">systemd
215</span><hr><div class=
"refentry"><a name=
"sd_get_seats"></a><div class=
"titlepage"></div><div class=
"refnamediv"><h2>Name
</h2><p>sd_get_seats, sd_get_sessions, sd_get_uids, sd_get_machine_names — Determine available seats, sessions, logged in users and virtual machines/containers
</p></div><div class=
"refsynopsisdiv"><h2>Synopsis
</h2><div class=
"funcsynopsis"><pre class=
"funcsynopsisinfo">#include
<systemd/sd-login.h
></pre><table border=
"0" class=
"funcprototype-table" summary=
"Function synopsis" style=
"cellspacing: 0; cellpadding: 0;"><tr><td><code class=
"funcdef">int
<b class=
"fsfunc">sd_get_seats
</b>(
</code></td><td>char ***
<var class=
"pdparam">seats
</var><code>)
</code>;
</td></tr></table><div class=
"funcprototype-spacer"> </div><table border=
"0" class=
"funcprototype-table" summary=
"Function synopsis" style=
"cellspacing: 0; cellpadding: 0;"><tr><td><code class=
"funcdef">int
<b class=
"fsfunc">sd_get_sessions
</b>(
</code></td><td>char ***
<var class=
"pdparam">sessions
</var><code>)
</code>;
</td></tr></table><div class=
"funcprototype-spacer"> </div><table border=
"0" class=
"funcprototype-table" summary=
"Function synopsis" style=
"cellspacing: 0; cellpadding: 0;"><tr><td><code class=
"funcdef">int
<b class=
"fsfunc">sd_get_uids
</b>(
</code></td><td>uid_t **
<var class=
"pdparam">users
</var><code>)
</code>;
</td></tr></table><div class=
"funcprototype-spacer"> </div><table border=
"0" class=
"funcprototype-table" summary=
"Function synopsis" style=
"cellspacing: 0; cellpadding: 0;"><tr><td><code class=
"funcdef">int
<b class=
"fsfunc">sd_get_machine_names
</b>(
</code></td><td>char ***
<var class=
"pdparam">machines
</var><code>)
</code>;
</td></tr></table><div class=
"funcprototype-spacer"> </div></div></div><div class=
"refsect1"><a name=
"idm214188979664"></a><h2 id=
"Description">Description
<a class=
"headerlink" title=
"Permalink to this headline" href=
"#Description">¶
</a></h2><p><code class=
"function">sd_get_seats()
</code> may be used
23 to determine all currently available local
24 seats. Returns a
<code class=
"constant">NULL
</code> terminated array of seat
25 identifiers. The returned array and all strings it
26 references need to be freed with the libc
27 <a href=
"free.html"><span class=
"citerefentry"><span class=
"refentrytitle">free
</span>(
3)
</span></a>
28 call after use. Note that instead of an empty array
29 <code class=
"constant">NULL
</code> may be returned and should be considered
30 equivalent to an empty array.
</p><p>Similarly,
<code class=
"function">sd_get_sessions()
</code> may
31 be used to determine all current login sessions.
</p><p>Similarly,
<code class=
"function">sd_get_uids()
</code> may
32 be used to determine all Unix users who currently have login sessions.
</p><p>Similarly,
33 <code class=
"function">sd_get_machine_names()
</code> may be
34 used to determine all current virtual machines and
35 containers on the system.
</p><p>Note that the returned lists are not sorted and in an undefined order.
</p></div><div class=
"refsect1"><a name=
"idm214188972032"></a><h2 id=
"Return Value">Return Value
<a class=
"headerlink" title=
"Permalink to this headline" href=
"#Return%20Value">¶
</a></h2><p>On success,
<code class=
"function">sd_get_seats()
</code>,
36 <code class=
"function">sd_get_sessions()
</code>,
37 <code class=
"function">sd_get_uids()
</code> and
38 <code class=
"function">sd_get_machine_names()
</code> return the
39 number of entries in the arrays. On failure, these
40 calls return a negative errno-style error code.
</p></div><div class=
"refsect1"><a name=
"idm214188967808"></a><h2 id=
"Notes">Notes
<a class=
"headerlink" title=
"Permalink to this headline" href=
"#Notes">¶
</a></h2><p>The
<code class=
"function">sd_get_seats()
</code>,
41 <code class=
"function">sd_get_sessions()
</code>,
42 <code class=
"function">sd_get_uids()
</code> and
43 <code class=
"function">sd_get_machine_names()
</code> interfaces
44 are available as a shared library, which can be compiled
45 and linked to with the
46 <code class=
"constant">libsystemd
</code> <a href=
"pkg-config.html"><span class=
"citerefentry"><span class=
"refentrytitle">pkg-config
</span>(
1)
</span></a>
47 file.
</p></div><div class=
"refsect1"><a name=
"idm214192866880"></a><h2 id=
"See Also">See Also
<a class=
"headerlink" title=
"Permalink to this headline" href=
"#See%20Also">¶
</a></h2><p>
48 <a href=
"systemd.html"><span class=
"citerefentry"><span class=
"refentrytitle">systemd
</span>(
1)
</span></a>,
49 <a href=
"sd-login.html"><span class=
"citerefentry"><span class=
"refentrytitle">sd-login
</span>(
3)
</span></a>,
50 <a href=
"sd_session_get_seat.html"><span class=
"citerefentry"><span class=
"refentrytitle">sd_session_get_seat
</span>(
3)
</span></a>
51 </p></div></div></body></html>