-static void do_cmd_knowledge_monsters(bool *need_redraw, bool visual_only, int direct_r_idx);
-static void do_cmd_knowledge_objects(bool *need_redraw, bool visual_only, int direct_k_idx);
-static void do_cmd_knowledge_features(bool *need_redraw, bool visual_only, int direct_f_idx, int *lighting_level);
+static void do_cmd_knowledge_monsters(bool *need_redraw, bool visual_only, IDX direct_r_idx);
+static void do_cmd_knowledge_objects(bool *need_redraw, bool visual_only, IDX direct_k_idx);
+static void do_cmd_knowledge_features(bool *need_redraw, bool visual_only, IDX direct_f_idx, int *lighting_level);