获取父类列表[重复]

Possible Duplicate:
php: determining class hierarchy of an object at runtime

Is there a way to get a list of parent classes for a certaint class?

For example:

class a{ 
    public function getParentsList(){...}
}

class b extends a{}

class c extends b{}

$c=new c;

var_dump($c->getParentsList());

should print array(a,b)

10x in advance