How to control the displayed precision when sending `std::chrono::locale_time` to a c++ stream?

Question

I'm almost happy with this:

const auto time = std::chrono::current_zone()->to_local(std::chrono::system_clock::now());
std::cout << time;

It prints:

2023-07-26 21:08:47.2889025

that's great, but I'd like it to print slightly less decimals, for instance:

2023-07-26 21:08:47.289

Is there some iomanip-like ways of specifying the desired precision? Something like:

std::cout << std::chrono::setprecision(3) << time;

Answer 1

Just floor it to milliseconds, either when you call now, or when you store it, or when you print it:

const auto time = std::chrono::current_zone()->to_local(std::chrono::system_clock::now());
std::cout << std::chrono::floor<std::chrono::milliseconds>(time);

Or use round or ceil depending on your rounding preference.