3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php var_dump(mb_convert_case('asdf', MB_CASE_UPPER, null));
based on dktGi
Output for 5.2.6 - 7.2.0
Warning: mb_convert_case(): Unknown encoding "(null)" in /in/NBmli on line 3 bool(false)
Output for 4.3.0 - 5.2.5
string(4) "ASDF"