t</span>. <span class="k">If</span> <span class="nv">IERR</span> <span class="nv">returns</span> <span class="nv">a</span> <span class="nv">non</span><span class="o">-</span><span class="nv">zero</span>
          <span class="nv">value</span> <span class="nv">an</span> <span class="nv">error</span> <span class="nv">occurred</span>.
 <span class="nv">onerr</span>    <span class="nv">The</span> <span class="nv">value</span> <span class="nv">to</span> <span class="k">return</span> <span class="nv">on</span> <s