These are nasty little corner-cases. I do wonder if the first two are worth worrying about: For (1) I can't see a use-case where it would be important. For (2

These are nasty little corner-cases. I do wonder if the first two are worth worrying about: For (1) I can't see a use-case where it would be important. For (2) Timing of this granularity is likely going to be done through nanosleep() and the POSIX.1 specification says that discontinuous changes in CLOCK_REALTIME should not affect nanosleep(). For (3) smearing, as Google and Amazon do, will handle it, as pointed out by others: https://developers.google.com/time/smear https://developers.google.com/time/smear