validate_url(&$url)

random_element($array)

subject($subject)

underscore($str)

cache($time)

create_captcha([$data = ''[, $img_path = ''[, $img_url = ''[, $font_path = '']]]])

memory_usage()

redirect($uri = '', $method = 'auto', $code = NULL)

do_upload([$field = 'userfile'])

unmark_temp($key)