That would break systems that relies on time stamps earlier than 1970 though. int main(void) { time_t epoch = -100; printf("%s", asctime(gmtime

That would break systems that relies on time stamps earlier than 1970 though. int main(void) { time_t epoch = -100; printf("%s", asctime(gmtime(&epoch))); } The above would for example print a time in 1969.