std::chrono::steady_clock::now
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std::chrono::steady_clock
Member functions
steady_clock::now
static std::chrono::time_point <std::chrono::steady_clock > now() noexcept;
(since C++11)
Returns a time point representing the current point in time.
[edit] Return value
A time point representing the current time.
[edit] 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