Checking if a class is a subclass of another

Question

I want to check if a class is a subclass of another without creating an instance. I have a class that receives as a parameter a class name, and as a part of the validation process, I want to check if it's of a specific class family (to prevent security issues and such). Any good way of doing this?

Answer 1

is_subclass_of() will correctly check if a class extends another class, but will not return true if the two parameters are the same (is_subclass_of('Foo', 'Foo') will be false).

A simple equality check will add the functionality you require.

function is_class_a($a, $b) {     return $a == $b || is_subclass_of($a, $b); }