Get Unix timestamp with C++

Question

How do I get a uint unix timestamp in C++? I've googled a bit and it seems that most methods are looking for more convoluted ways to represent time. Can't I just get it as a uint?

Answer 1

C++20 introduced a guarantee that time_since_epoch is relative to the UNIX epoch, and cppreference.com gives an example that I've distilled to the relevant code, and changed to units of seconds rather than hours:

#include <iostream> #include <chrono>   int main() {     const auto p1 = std::chrono::system_clock::now();       std::cout << "seconds since epoch: "               << std::chrono::duration_cast<std::chrono::seconds>(                    p1.time_since_epoch()).count() << '\n'; } 

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Using C++17 or earlier, time() is the simplest function - seconds since Epoch, which for Linux and UNIX at least would be the UNIX epoch. Linux manpage here.

The cppreference page linked above gives this example:

#include <ctime> #include <iostream>   int main() {     std::time_t result = std::time(nullptr);     std::cout << std::asctime(std::localtime(&result))               << result << " seconds since the Epoch\n"; }