+void proc_discard_active_file (struct dataset *);
+void proc_set_active_file (struct dataset *,
+ struct casereader *, struct dictionary *);
+bool proc_set_active_file_data (struct dataset *, struct casereader *);
+bool proc_has_active_file (const struct dataset *ds);
+struct casereader *proc_extract_active_file_data (struct dataset *);