This is what I'd _like_ to do, but unfortunately it's not well supported. As far as I know, all OSes store the time including leap seconds, so there's no way to

This is what I'd _like_ to do, but unfortunately it's not well supported. As far as I know, all OSes store the time including leap seconds, so there's no way to go back to TAI. And even if it were, that time zone is not available in user programs. edit: Oh, I see that it's available in Linux https://www.man7.org/linux/man-pages/man3/clock_gettime.3.html https://www.man7.org/linux/man-pages/man3/clock_gettime.3.ht... . Can't find similar calls for Windows or OSX