- gmmktime: documentation ( source)
- gmdate: documentation ( source)
<?php
// Everything you enter here will be executed by our servers. Try it!
$t = gmmktime(11, 59, 59, 9, 2, 2013);
echo gmdate('Y-m-d H:i:s', $t), "\n";
echo gmdate('Y-m-d H:i:s', $t - 12 * 3600), "\n";