open: procedure(aft,file,access,mode,status) external;
    declare (aft,file,access,mode,status) address;
    end open;
close:  procedure (aft,status) external;
    declare (aft,status) address;
    end close;
read:   procedure (aft,buffer,count,actual,status) external;
    declare (aft,buffer,count,actual,status) address;
    end read;
write:  procedure (aft,buffer,count,status) external;
    declare (aft,buffer,count,status) address;
    end write;
exit:   procedure external;
    declare status address;
    end exit;
error:  procedure (errnum) external;
    declare (errnum,status) address;
    end error;