A general solution to the overflowing-clock problem is to deal with the clock in modular arithmetic. When wanting to know if t2 comes before t1, check the MSB o

A general solution to the overflowing-clock problem is to deal with the clock in modular arithmetic. When wanting to know if t2 comes before t1, check the MSB of the modular difference. uint32_t t1 = ...; uint32_t t2 = ...; if ((uint32_t)(t2 - t1) >= UINT32_C(0x80000000)) { // t2 is before t1 } else { // t2 is after or equal to t1 } What this gives us is that if the difference of the actual times (not these uint32 representations which are ambiguous modulo 2^32) is less than 2^31 units (plus minus one maybe..), this check will give the expected result. This does allow a correct system that never fails if the timing/duration of the events is suitably limited. For example you time events at a fixed time interval, and it will keep going forever in spite of clock roll-over. uint32_t next_time = now(); while (1) { while ((uint32_t)(now() - next_time) >= UINT32_C(0x80000000)); printf("Shoot\n"); next_time += interval; } The timing events also need to be processed quickly enough of course (that printf shouldn't block for longer than about 2^31).