r> and <var class="Ar">idp</var> should be passed
    since only the extra field data is returned (i.e., neither the ID nor the
    length, if the <var class="Ar">idp</var> and <var class="Ar">lenp</var>
    arguments are not provided).</p>
<p class="Pp">The following <var class="Ar">flags</var> are supported:</p>
<div class="Bd-indent">
<dl class="Bl-tag">
  <dt id="ZIP_FL_CENTRAL"><a class="permalink" href="#ZIP_FL_CENTRAL"><code class="Dv">ZIP_FL_CENTRAL</code></a></dt>
  <dd>Return extra fields from the