run code in 200+ php & hhvm versions
Bugs & Features
<?php $string = "♫"; $len = mb_strlen($string, '8bit'); for($i=0;$i<$len;++$i) echo mb_substr($str, $i, 1, 'UTF-8')."<br/>"

Here you find the average performance (time & memory) of each version. A grayed out version indicates it didn't complete successfully (based on exit-code).
Note: hhvm uses a JIT which only kicks in after a few runs. Since we run scripts only once, hhvm always runs slower.

VersionSystem time (s)User time (s)Memory (MiB)