domain_user_strip_chars($name)
domain_user/domain_user.module, line 336
Turn a user name into a domain-safe string.
$name The user name to process.
A string with only alphanumeric characters and dashes.
function domain_user_strip_chars($name) {
// Only alphanumeric characters are allowed.
$pattern = '/[^a-zA-Z0-9]/';
$name = preg_replace($pattern, '-', $name);
return strtolower($name);
}