25 Time library [time]

25.7 Clocks [time.clock]

25.7.3 Class tai_­clock [time.clock.tai]

25.7.3.2 Member functions [time.clock.tai.members]

static time_point now();
Returns: from_­utc(utc_­clock::now()), or a more accurate value of tai_­time.
template<class Duration> static utc_time<common_type_t<Duration, seconds>> to_utc(const tai_time<Duration>& t) noexcept;
Returns:
utc_time<common_type_t<Duration, seconds>>{t.time_since_epoch()} - 378691210s
[Note
:
378691210s == sys_days{1970y/January/1} - sys_days{1958y/January/1} + 10s
end note
]
template<class Duration> static tai_time<common_type_t<Duration, seconds>> from_utc(const utc_time<Duration>& t) noexcept;
Returns:
tai_time<common_type_t<Duration, seconds>>{t.time_since_epoch()} + 378691210s
[Note
:
378691210s == sys_days{1970y/January/1} - sys_days{1958y/January/1} + 10s
end note
]