typedef int PK_TOPOL_track_t; This data type indicates what type of tracking data is being output. It has four values: PK_TOPOL_track_delete_c marks deletion of topologies PK_TOPOL_track_merge_c marks deletion of topology by merging PK_TOPOL_track_create_c marks creation of topology from scratch or by copying PK_TOPOL_track_split_c marks creation of topology by sub-division PK_TOPOL_track_derive_c marks creation of topology by combination of merging and splitting