CODEWITHSUNDEEP
c++epochc++-chrono
Narek
Narek

Reputation: 39881

C++ chrono epoch is 100000 times smaller?

THe code below returns number like 14517044:

typedef std::chrono::high_resolution_clock Clock;
typedef std::chrono::milliseconds Milliseconds;
unsigned long res = std::chrono::duration_cast<Milliseconds>(Clock::now().time_since_epoch()).count();
printf("epoch %lu", res);

But http://www.epochconverter.com/ site shows numbers like 1426143327, where as it is in seconds. So the epoch with Milliseconds has 8 digits and epoch with seconds has 10 digits?

What is wrong in my code?

Upvotes: 0

Views: 210

Answers (1)

Tony Delroy
Tony Delroy

Reputation: 106066

Beware - not all computers use the same date/time for their epoch. Anyway, your problem is truncation of the value to 32 bits... it needs more.

#include <cstdio>
#include <iostream>
#include <chrono>

int main()
{
    typedef std::chrono::high_resolution_clock Clock;
    typedef std::chrono::milliseconds Milliseconds;
    auto res = std::chrono::duration_cast<Milliseconds>(Clock::now().time_since_epoch()).count();
    printf("garbage %lu\n", res);  // garbage
    printf("epoch printf %lld\n", (long long)res);
    std::cout << "epoch cout " << res << '\n';
}

Output:

garbage 202650458
epoch printf 1426131792730
epoch cout 1426131792730

See it run here

Upvotes: 3

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