Description:
------------
According to http://php.net/manual/en/function.get-resource-type.php get_resource_type should return FALSE if $handle is not a resource, but it returns NULL.
I reckon that returning false is the proper response and that following the documentation is the more sane option.

Test script:
---------------
<?php
var_dump(@get_resource_type("not_a_resource"));
?>

Expected result:
----------------
bool(false)

Actual result:
--------------
NULL