(PHP 5 >= 5.2.0, PECL zip >= 1.4.0)
ZipArchive::setCommentName — Set the comment of an entry defined by its name
$name
   , string $comment
   )Set the comment of an entry defined by its name.
nameName of the entry.
commentThe contents of the comment.
   Returns TRUE on success or FALSE on failure.
  
Example #1 Open an archive and set a comment for an entry
<?php
$zip = new ZipArchive;
$res = $zip->open('test.zip');
if ($res === TRUE) {
    $zip->setCommentName('entry1.txt', 'new entry comment');
    $zip->close();
    echo 'ok';
} else {
    echo 'failed';
}
?>