/* write the empty data area */
if ((unknown = (rrd_value_t *) malloc(512 * sizeof(rrd_value_t))) == NULL) {
rrd_set_error("allocating unknown");
/* write the empty data area */
if ((unknown = (rrd_value_t *) malloc(512 * sizeof(rrd_value_t))) == NULL) {
rrd_set_error("allocating unknown");