(PHP 4 >= 4.2.0, PHP 5)
mb_regex_encoding — Returns current encoding for multibyte regex as string
mb_regex_encoding() returns the character encoding used by multibyte regex functions.
If the optional parameter encoding is specified, it is set to the character encoding for multibyte regex. The default value is the internal character encoding.
See also: mb_internal_encoding(), mb_ereg()