the higher
    <var class="Ar">version_needed</var> is used, and
    <var class="Ar">general_purpose_bit_flags</var> are only overwritten if the
    corresponding bit is set in
  <var class="Ar">general_purpose_bit_mask</var>.</p>
</section>
<section class="Ss">
<h2 class="Ss" id="ZIP_SOURCE_OPEN"><a class="permalink" href="#ZIP_SOURCE_OPEN"><code class="Dv">ZIP_SOURCE_OPEN</code></a></h2>
<p class="Pp">The lower layer is opened before the callback is called.</p>
</section>
<section class="Ss">
<h2 class="S