> must also call <b>chkout_c</b>, or else the
   trace mechanism will become very confused and need alot of therapy.

   It is possible to disable check-ins (and check-outs) by calling
   the <a href="trcoff_c.html">trcoff_c</a>.  <a href="chkin_c.html">chkin_c</a> and <b>chkout_c</b> will return immediately
   upon entry after <a href="trcoff_c.html">trcoff_c</a> has been called.  It is not possible to
   re-enable check-ins and check-outs after calling <a href="trcoff_c.html">trcoff_c</a>. Routines
   tha