- TR(TRACE_MOVE, ("mvcur_scrolln(%d, %d, %d, %d)", n, top, bot, maxy));
+ TR(TRACE_MOVE, ("_nc_scrolln(%p, %d, %d, %d, %d)",
+ (void *) SP_PARM, n, top, bot, maxy));
+
+ if (!IsValidScreen(SP_PARM))
+ return (ERR);
+
+ blank = ClrBlank(NCURSES_SP_ARGx StdScreen(SP_PARM));