* NB Note the difference between $errorlevel = false and
* $errorlevel = 0
* @param array $parsedata If passed, returns the parsed address components
+ * @return bool|int
*/
/*.mixed.*/ function is_email($email, $checkDNS = false, $errorlevel = false, &$parsedata = array()) {
// Check that $email is a valid address. Read the following RFCs to understand the constraints: