 a longer slot, the
application needs to issue a <a href="../api_reference/C/lockvec.html" class="olink">DB_ENV-&gt;lock_vec()</a> call, with one
<a href="../api_reference/C/lockget.html" class="olink">DB_ENV-&gt;lock_get()</a> operation per half-hour — up to the total length.  If
the <a href="../api_reference/C/lockvec.html" class="olink">DB_ENV-&gt;lock_vec()</a> call fails, the application would have to release
the parts of the time slot that were obtained.</p>
      <p>To cancel a reservation, the app