3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $str = 'a,b\,c,d'; var_dump(preg_split('/(?<!(?<=\\\\)\\\\),/', $str));
based on UpsgS
Output for 4.3.0 - 7.1.0
array(4) { [0]=> string(1) "a" [1]=> string(2) "b\" [2]=> string(1) "c" [3]=> string(1) "d" }