<?php
$p = new Phar(dirname(__FILE__) . '/my.phar', 0, 'my.phar');
$p['firstfile.txt'] = 'first file';
$p['secondfile.txt'] = 'second file';
// the next set of lines call offsetExists() indirectly
var_dump(isset($p['firstfile.txt']));
var_dump(isset($p['nothere.txt']));
?>
The above example will output: