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std::chrono::time_point::time_point(3) C++ Standard Libary std::chrono::time_point::time_point(3)


std::chrono::time_point::time_point - std::chrono::time_point::time_point


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


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

constructor constructs new duration
(public member function of std::chrono::duration<Rep,Period>)
duration_cast converts a duration to another, with a different tick interval
(C++11) (function template)