c++c++11c++-chrono

How to convert std::chrono::duration to double (seconds)?

Let's have using duration = std::chrono::steady_clock::duration. I would like to convert duration to double in seconds with maximal precision elegantly.

I have found the reverse way, but it didn't help me finding it out.

Alternatively expressed, I want optimally some std function double F(duration), which returns seconds.

Solution

  • Simply do:

    std::chrono::duration<double>(d).count()

    Or, as a function:

    template <class Rep, class Period>
constexpr auto F(const std::chrono::duration<Rep,Period>& d)
{
    return std::chrono::duration<double>(d).count();
}

    If you need more complex casts that cannot be fulfilled by the std::chrono::duration constructors, use std::chrono::duration_cast.