valid_object - allows control over which objects can be loaded
int valid_object( object obj );
After loading an object, the driver will call valid_object() with the newly created object as its argument, in the master object. If the function exists, and returns 0, then the object will be destructed and the efun that caused it to load will error out. If it does not exist, or returns 1, then loading will proceed as normal. In conjunction with 'nomask' and the inherits() efun, this could allow safely restricting destruct() via a simul_efun.