Here is the public interfaces of LinearHashingScan. Notice that the constructor for LinearHashingScan is not public. A scan can only be created by calling LinearHashingFile::new_scan.
class LinearHashingScan : public IndexFileScan {
public:
// get the next record
Status get_next(RID & rid);
// delete the record currently scanned
Status delete_current();
// destructor
~LinearHashingScan();
};