an obtain the ID of body-fixed frame 
           associated with the segment. We'll need this frame
           later to compute illumination angles on the target
           body's reference ellipsoid.
           ./
           <a href="dskgd_c.html">dskgd_c</a> ( handle, &amp;dladsc, &amp;dskdsc );

           <a href="frmnam_c.html">frmnam_c</a> ( dskdsc.frmcde, FRNMLN, fixref );

           if ( <a href="eqstr_c.html">eqstr_c</a>(fixref, &quot; &quot;) )
           {
              <a href="setmsg_c.html">s