run code in 200+ php & hhvm versions
Bugs & Features
<?php function &g(&$v) { return $v; } function f(&$v) { $v = 5; } $foo = null; $name = 'foo'; call_user_func_array('f', array(g(&$$name))); //var_dump(array(g($$name))); var_dump($foo);

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)