- mb_convert_encoding: documentation ( source)
- var_dump: documentation ( source)
- preg_match_all: documentation ( source)
- preg_quote: documentation ( source)
<?php
$text = <<<TXT
/some text/
TXT;
$pattern = "/ัะตัั";
$pattern = mb_convert_encoding($pattern, 'UTF-8', 'Windows-1251');
$pattern = preg_quote($pattern, '/');
$pattern = mb_convert_encoding($pattern, 'Windows-1251', 'UTF-8');
var_dump($pattern);
$matches = array();
$match = preg_match_all("/" . $pattern . "/mi", $text, $matches);
var_dump($match, $matches);