Some weeks ago I asked if there is the need for a function which measures the execution time of another function, but nobody responded. Could you please give me a short feedback.

Possible implementation:

template <typename Duration, typename Result>

    struct measurement_result {

    Duration duration;

    Result result;

};

template <

        typename Clock = std::chrono::high_resolution_clock,

        typename F, typename... Args>

auto measure_ignore_result(F f, Args&&... args)

{

    auto const start = Clock::now();

    f(std::forward<Args>(args)...);

    auto const stop = Clock::now();

    auto const duration = stop - start;

    return measurement_result<decltype(duration), std::monostate>{duration};

}

template <

        typename Clock = std::chrono::high_resolution_clock,

        typename F, typename... Args,

        std::enable_if_t<std::is_void_v<std::result_of_t<F(Args...)>>, bool> = true>

auto measure(F f, Args&&... args)

{

    return measure_ignore_result(

            std::forward<F>(f), std::forward<Args>(args)...);

}

template <

        typename Clock = std::chrono::high_resolution_clock,

        typename F, typename... Args,

        std::enable_if_t<!std::is_void_v<std::result_of_t<F(Args...)>>, bool> = true>

auto measure(F f, Args&&... args)

{

    auto const start = Clock::now();

    auto const result = f(std::forward<Args>(args)...);

    auto const stop = Clock::now();

    auto const duration = stop - start;

    return measurement_result{duration, result};

}

Usage:

auto fib(int i) -> int

{

    return i <= 1 ? i : fib(i-1) + fib(i-2);

}

auto main() -> int

{

    std::cout << std::chrono::duration<double>(measure(fib, 42).duration).count();

}

Paul Raffer

--
Std-Proposals mailing list
Std-Proposals@lists.isocpp.org
https://lists.isocpp.org/mailman/listinfo.cgi/std-proposals