It was 5.3 that gained the 64-bit time API. Prior to that, there was only 32-bit time_t, even on 64-bit AIX. See Redbook SG247463 section 5.19 ("Date APIs pas

It was 5.3 that gained the 64-bit time API. Prior to that, there was only 32-bit time_t, even on 64-bit AIX. See Redbook SG247463 section 5.19 ("Date APIs past 2038").