echo '>>>$s_umm='.($s_umm).'<br/>';
    echo '>>>substr='.substr($s_umm, 0, 1).'<br/>';
    echo '>>>mb_substr='.mb_substr($s_umm, 0, 1).'<br/>';

array(15) {
  ["internal_encoding"]=>
  string(5) "UTF-8"
  ["http_input"]=>
  string(0) ""
  ["http_output"]=>
  string(4) "pass"
  ["http_output_conv_mimetypes"]=>
  string(31) "^(text/|application/xhtml\+xml)"
  ["func_overload"]=>
  int(2)
  ["func_overload_list"]=>
  array(12) {
    ["strlen"]=>
    string(9) "mb_strlen"
    ["strpos"]=>
    string(9) "mb_strpos"
    ["strrpos"]=>
    string(10) "mb_strrpos"
    ["stripos"]=>
    string(10) "mb_stripos"
    ["strripos"]=>
    string(11) "mb_strripos"
    ["strstr"]=>
    string(9) "mb_strstr"
    ["strrchr"]=>
    string(10) "mb_strrchr"
    ["stristr"]=>
    string(10) "mb_stristr"
    ["substr"]=>
    string(9) "mb_substr"
    ["strtolower"]=>
    string(13) "mb_strtolower"
    ["strtoupper"]=>
    string(13) "mb_strtoupper"
    ["substr_count"]=>
    string(15) "mb_substr_count"
  }
  ["mail_charset"]=>
  string(5) "UTF-8"
  ["mail_header_encoding"]=>
  string(6) "BASE64"
  ["mail_body_encoding"]=>
  string(6) "BASE64"
  ["illegal_chars"]=>
  int(0)
  ["encoding_translation"]=>
  string(3) "Off"
  ["language"]=>
  string(7) "neutral"
  ["detect_order"]=>
  array(2) {
    [0]=>
    string(5) "ASCII"
    [1]=>
    string(5) "UTF-8"
  }
  ["substitute_character"]=>
  int(63)
  ["strict_detection"]=>
  string(3) "Off"
}