src/Drupal/Component/Utility/Unicode.php
public static function strtolower($text) {
    if (static::getStatus() == static::STATUS_MULTIBYTE) {
      return mb_strtolower($text);
    }
    else {
      // Use C-locale for ASCII-only lowercase.
      $text = strtolower($text);
      // Case flip Latin-1 accented letters.
      $text = preg_replace_callback('/\xC3[\x80-\x96\x98-\x9E]/', '\Drupal\Component\Utility\Unicode::caseFlip', $text);
      return $text;
    }
  }
public static function strtolower($text) {
    if (static::getStatus() == static::STATUS_MULTIBYTE) {
      return mb_strtolower($text);
    }
    else {
      // Use C-locale for ASCII-only lowercase.
      $text = strtolower($text);
      // Case flip Latin-1 accented letters.
      $text = preg_replace_callback('/\xC3[\x80-\x96\x98-\x9E]/', '\Drupal\Component\Utility\Unicode::caseFlip', $text);
      return $text;
    }
  }
public static function strtolower ( $ text ) { if ( static :: getStatus ( ) == static :: STATUS_MULTIBYTE ) { return mb_strtolower ( $ text ) ; } else { // Use C-locale for ASCII-only lowercase. $ text = strtolower ( $ text ) ; // Case flip Latin-1 accented letters. $ text = preg_replace_callback ( '/\xC3[\x80-\x96\x98-\x9E]/' , '\Drupal\Component\Utility\Unicode::caseFlip' , $ text ) ; return $ text ; } }
Converts a UTF-8 string to lowercase.

@param string $text
The string to run the operation on.

@return string
The string in lowercase.
Converts a UTF - 8 string to lowercase .