How to check if a variable is of a certian class (considering PHP 5.3 namespace too)

How can I validate if an object is of a certian class? I currently use

get_class($obj) == 'User';

But it may look like 开发者_运维百科\KM\User when I am elsewhere? I think this way maybe abit prone to developer error. Is there something like:

compare_class($obj1, User);
// or maybe
classof($obj) == User;

Use the instanceof operator:

if($foo instanceof User) {
    ...
}

Just

if ($obj instanceof User) {
  // $obj is of User or any descendant
}

should do it. This is affected by the 5.3 namespace handling, which means: If you are in my\namespace, it assume User to be \my\namespace\User. Or if you have something like use another\namespace\User it will be treated as exactly that class specified by the use-statement.