The PIF object class contains just the PIF object's name, its handle, and a variable holding the update mode used for writing the object back to a PLB. Other GRS methods rely on the Check() method which searches and checks a PIF object requested by a certain application.
The PIF object reference class is a child of the PIF object class, and contains additional members that hold a PIF object's reference handles. This class is used by GRS as a parent for all GRS classes of PIF objects referencing other PIF objects such as grids and attributes. Two essential methods are implemented by this class for reading and writing of those reference handles from and to a PIF binary file.