- var_dump: documentation ( source)
- preg_match: documentation ( source)
<?php
var_dump(preg_match('/あ/u', "\xE38182", $matches));
var_dump(preg_match('//u', "\xF0A0808B", $matches));
var_dump(preg_match('//u', "𠀋", $matches));
var_dump("\xF0A0808B" == "𠀋");