e class="Dv">NULL</code> is returned and the error code in
    <var class="Ar">archive</var> is set to indicate the error.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="ERRORS"><a class="permalink" href="#ERRORS">ERRORS</a></h1>
<p class="Pp"><code class="Fn">zip_file_get_comment</code>() fails if:</p>
<dl class="Bl-tag">
  <dt id="ZIP_ER_INVAL">[<a class="permalink" href="#ZIP_ER_INVAL"><code class="Er">ZIP_ER_INVAL</code></a>]</dt>
  <dd><var class="Ar">index</var> is not a valid file index in
  