25 Time library [time]

25.7 Clocks [time.clock]

25.7.5 Class file_­clock [time.clock.file] Overview [time.clock.file.overview]

namespace std::chrono {
  class file_clock {
    using rep                       = a signed arithmetic type;
    using period                    = ratio<unspecified, unspecified>;
    using duration                  = chrono::duration<rep, period>;
    using time_point                = chrono::time_point<file_clock>;
    static constexpr bool is_steady = unspecified;

    static time_point now() noexcept;

    // Conversion functions, see below
The clock file_­clock is used to create the time_­point system used for file_­time_­type ([filesystems]).
Its epoch is unspecified.