3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php preg_match('/(?>[A-Za-z])+[A-Za-z]+/', 'FooBar', $m); var_dump($m); preg_match('/[A-Za-z]++[A-Za-z]+/', 'FooBar', $m); var_dump($m);
based on eqKvQ
Output for 4.3.0 - 5.6.28, hhvm-3.10.0 - 3.12.0, 7.0.0 - 7.1.0
array(1) { [0]=> string(6) "FooBar" } array(0) { }