26 Time library [time]

26.7 Clocks [time.clock]

26.7.5 Type file_­clock [time.clock.file]

26.7.5.2 Member functions [time.clock.file.members]

The type denoted by file_­clock provides precisely one of the following two sets of static member functions:
template<class Duration>
  static sys_time<see below>
    to_sys(const file_time<Duration>&);
template<class Duration>
  static file_time<see below>
    from_sys(const sys_time<Duration>&);
or:
template<class Duration>
  static utc_time<see below>
    to_utc(const file_time<Duration>&);
template<class Duration>
  static file_time<see below>
    from_utc(const utc_time<Duration>&);
These member functions shall provide time_­point conversions consistent with those specified by utc_­clock, tai_­clock, and gps_­clock.
The Duration of the resultant time_­point is computed from the Duration of the input time_­point.