29 Time library [time]

29.7 Clocks [time.clock]

29.7.6 Type file_clock [time.clock.file]

29.7.6.2 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.