} static function getInstance() { if (self::$con instanceof self) { return self::$con; } else { self::$con = new self(); return self::$con; } } } class t extends M { } $t1 = t::getInstance(); $t2 = t::getInstance(); $t3 = clone $t2; var_dump($t1); var_dump($t2); var_dump($t3); if ($t1 === $t2) { echo 't1 === t2<br/>'; } else { echo 't1!==t2<br/>'; } if ($t2 === $t3) { echo 't2 === t3<br/>'; } else { echo 't2!== t3<br/>'; } /*