[time-nuts] Mac OS and iOS leap second handling

[Eric Scace]

   Maybe someone on the list has a recent and authoritative answer to the following questions.

   I’ve been digging around in “civilian mode” (not an OS X or iOS developer) trying to determine if current Mac OS X and iOS releases handle leap seconds:
no smearing
proper display of 23:59:60, etc on the system clock & return of same to appropriate function calls.

   I have not been able to discover a well-documented answer to this question; e.g., video of an OS X/iOS system clock displaying a leap second, or Apple-sourced documentation stating leap second support.

   There are assertions that OS X was built around POSIX and suffers from the limitations of Unix epoch time decisions of long ago. Is that still the case?

   (In contrast, Microsoft docs claim Win 2018 Oct and Win Server 2019 now have leap second support.)

Thanks,
   — Eric