- var_dump: documentation ( source)
- str_repeat: documentation ( source)
- preg_match_all: documentation ( source)
<?php
$str = "a".str_repeat("\xCC\x8A", 100000);
var_dump(
1 === preg_match_all('/\X/u', $str),
1 === preg_match_all('/(?>\PM\pM*)/u', $str)
);