3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php var_dump(JSON_UNESCAPED_UNICODE);
Output for 5.4.0 - 7.1.0
int(256)
Output for 4.3.0 - 5.3.29
Notice: Use of undefined constant JSON_UNESCAPED_UNICODE - assumed 'JSON_UNESCAPED_UNICODE' in /in/XiPvL on line 3 string(22) "JSON_UNESCAPED_UNICODE"