man/sd_get_machine_names.html

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  22   <a href="../libudev/index.html">gudev </a><span style="float:right">systemd 214</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 &lt;systemd/sd-login.h&gt;</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="idm214192262480"></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="idm214195789600"></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="idm214192004480"></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="idm214191998928"></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>