std::chrono::time_point<Clock,Duration>::time_point (3) - Linux Manuals

std::chrono::time_point<Clock,Duration>::time_point: std::chrono::time_point<Clock,Duration>::time_point


std::chrono::time_point<Clock,Duration>::time_point - std::chrono::time_point<Clock,Duration>::time_point


time_point(); (since C++11)
                                                                      (until C++14)
constexpr time_point(); (since C++14)
explicit time_point( const duration& d ); (since C++11)
                                                              (1) (until C++14)
constexpr explicit time_point( const duration& d ); (since C++14)
template< class Duration2 > (2) (since C++11)
time_point( const time_point<Clock,Duration2>& t ); (3) (until C++14)
template< class Duration2 > (since C++14)
constexpr time_point( const time_point<Clock,Duration2>& t );

Constructs a new time_point from one of several optional data sources.
1) Default constructor, creates a time_point representing the Clock's epoch (i.e., time_since_epoch() is zero).
2) Constructs a time_point at Clock's epoch plus d.
3) Constructs a time_point by converting t to duration. This constructor only participates in overload resolution if Duration2 is implicitly convertible to duration.


d - a duration to copy from
t - a time_point to convert from


// Run this code

  #include <chrono>
  #include <iostream>

  using Clock = std::chrono::high_resolution_clock;
  using TimePoint = std::chrono::time_point<Clock>;

  void print_ms(const TimePoint& point)
      using Ms = std::chrono::milliseconds;
      const Clock::duration since_epoch = point.time_since_epoch();
      std::cout << std::chrono::duration_cast<Ms>(since_epoch).count() << " ms\n";

  int main()
      const TimePoint default_value = TimePoint(); // (1)
      print_ms(default_value); // 0 ms

      const Clock::duration duration_4_seconds = std::chrono::seconds(4);
      const TimePoint time_point_4_seconds(duration_4_seconds); // (2)
        // 4 seconds from start of epoch
      print_ms(time_point_4_seconds); // 4000 ms

      const TimePoint time_point_now = Clock::now(); // (3)
      print_ms(time_point_now); // 43098276 ms

Possible output:

  0 ms
  4000 ms
  43098276 ms

See also

              constructs new duration
constructor (public member function of std::chrono::duration<Rep,Period>)
              converts a duration to another, with a different tick interval
duration_cast (function template)