$cacheDir = '../cache/runtime';
$dh = opendir($cacheDir);
while ( $file = readdir($dh) ) {

if (($file == '.') || ($file == '..')) { continue; }

if (file_exists( $cacheDir . '/' .$file)) {
if (!unlink($cacheDir . '/' . $file)) {
break;
}
}
}