# std::chrono::steady_clock::now

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< cpp‎ | chrono‎ | steady clock

static std::chrono::time_point < std::chrono::steady_clock > now() noexcept; |  | (since C++11)

Returns a time point representing the current point in time.

### Return value

A time point representing the current time.

### Example

Run this code

    #include <chrono>
    #include <cstddef>
    #include <iomanip>
    #include <iostream>
    #include <numeric>
    #include <vector>

    volatile int sink; // prevents optimization

    void do_some_work(std::size_t size)
    {
        std::vector<int> v(size, 42);
        sink = std::accumulate(v.begin(), v.end(), 0); // ensures side effect
    }

    int main()
    {
        std::cout << std::fixed << std::setprecision(9) << std::left;
        for (auto size{1ull}; size < 1000'000'000ull; size *= 100)
        {
            const auto start = std::chrono::steady_clock::now();
            do_some_work(size);
            const auto end = std::chrono::steady_clock::now();
            const std::chrono::duration<double> diff = end - start;

            std::cout << "diff = " << diff << "; size = " << size << '\n';
        }
    }

Possible output:

    diff = 0.000005415s; size = 1
    diff = 0.000001986s; size = 100
    diff = 0.000051633s; size = 10000
    diff = 0.006043920s; size = 1000000
    diff = 0.636128648s; size = 100000000

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