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- <a href="../libudev/index.html">gudev </a><span style="float:right">systemd 21
5</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
+ <a href="../libudev/index.html">gudev </a><span style="float:right">systemd 21
7</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="idm214182274704"></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
to determine all currently available local
seats. Returns a <code class="constant">NULL</code> terminated array of seat
identifiers. The returned array and all strings it
references need to be freed with the libc
- <a href="free.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
+ <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
call after use. Note that instead of an empty array
<code class="constant">NULL</code> may be returned and should be considered
equivalent to an empty array.</p><p>Similarly, <code class="function">sd_get_sessions()</code> may
be used to determine all Unix users who currently have login sessions.</p><p>Similarly,
<code class="function">sd_get_machine_names()</code> may be
used to determine all current virtual machines and
- 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="idm21418
8972032"></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>,
+ 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="idm21418
2266800"></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>,
<code class="function">sd_get_sessions()</code>,
<code class="function">sd_get_uids()</code> and
<code class="function">sd_get_machine_names()</code> return the
number of entries in the arrays. On failure, these
- calls return a negative errno-style error code.</p></div><div class="refsect1"><a name="idm21418
8967808"></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>,
+ calls return a negative errno-style error code.</p></div><div class="refsect1"><a name="idm21418
6167504"></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>,
<code class="function">sd_get_sessions()</code>,
<code class="function">sd_get_uids()</code> and
<code class="function">sd_get_machine_names()</code> interfaces
are available as a shared library, which can be compiled
and linked to with the
- <code class="constant">libsystemd</code> <a href="pkg-config.html"><span class="citerefentry"><span class="refentrytitle">pkg-config</span>(1)</span></a>
- file.</p></div><div class="refsect1"><a name="idm2141
92866880"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also">¶</a></h2><p>
+ <code class="constant">libsystemd</code> <a href="http://linux.die.net/man/1/pkg-config"><span class="citerefentry"><span class="refentrytitle">pkg-config</span>(1)</span></a>
+ file.</p></div><div class="refsect1"><a name="idm2141
86161680"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also">¶</a></h2><p>
<a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>,
<a href="sd-login.html"><span class="citerefentry"><span class="refentrytitle">sd-login</span>(3)</span></a>,
<a href="sd_session_get_seat.html"><span class="citerefentry"><span class="refentrytitle">sd_session_get_seat</span>(3)</span></a>
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