duration time_since_epoch() const; | (since C++11) (until C++14) | |
constexpr duration time_since_epoch() const; | (since C++14) |
Returns a duration representing the amount of time between *this and the clock's epoch.
Parameters
(none).
Return value
The amount of time between this time_point and the clock's epoch.
Example
#include <iostream>
#include <chrono>
#include <ctime>
int main()
{
std::chrono::time_point<std::chrono::system_clock> p1, p2, p3;
p2 = std::chrono::system_clock::now();
p3 = p2 - std::chrono::hours(24);
std::time_t epoch_time = std::chrono::system_clock::to_time_t(p1);
std::cout << "epoch: " << std::ctime(&epoch_time);
std::time_t today_time = std::chrono::system_clock::to_time_t(p2);
std::cout << "today: " << std::ctime(&today_time);
std::cout << "hours since epoch: "
<< std::chrono::duration_cast<std::chrono::hours>(
p2.time_since_epoch()).count()
<< '\n';
std::cout << "yesterday, hours since epoch: "
<< std::chrono::duration_cast<std::chrono::hours>(
p3.time_since_epoch()).count()
<< '\n';
}Possible output:
epoch: Wed Dec 31 19:00:00 1969 today: Tue Jun 19 12:05:37 2012 hours since epoch: 372256 yesterday, hours since epoch: 372232
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