Defined in header <chrono> | ||
|---|---|---|
template <class Rep>
struct treat_as_floating_point : std::is_floating_point<Rep> {};
| (since C++11) |
The std::chrono::treat_as_floating_point trait helps determine if a duration can be converted to another duration with a different tick period.
Implicit conversions between two durations normally depends on the tick period of the durations. However, implicit conversions can happen regardless of tick period if std::chrono::treat_as_floating_point<Rep>::value == true.
template< class Rep > inline constexpr bool treat_as_floating_point_v = treat_as_floating_point<Rep>::value; | (since C++17) |
std::chrono::treat_as_floating_point may be specialized for program-defined types.
#include <iostream>
#include <chrono>
#include <thread>
void timed_piece_of_code()
{
std::chrono::milliseconds simulated_work(2);
std::this_thread::sleep_for(simulated_work);
}
int main()
{
auto start = std::chrono::high_resolution_clock::now();
std::cout << "Running some timed piece of code..." << '\n';
timed_piece_of_code();
auto stop = std::chrono::high_resolution_clock::now();
// A floating point milliseconds type
using FpMilliseconds =
std::chrono::duration<float, std::chrono::milliseconds::period>;
static_assert(std::chrono::treat_as_floating_point<FpMilliseconds::rep>::value,
"Rep required to be floating point");
// Note that implicit conversion is not allowed here
auto i_ms = std::chrono::duration_cast<std::chrono::milliseconds>(stop - start);
// Note that implicit conversion is allowed here
auto f_ms = FpMilliseconds(stop - start);
std::cout << "Timing stats: " << '\n';
std::cout << " Time in milliseconds, using default rep: "
<< i_ms.count() << '\n';
std::cout << " Time in milliseconds, using floating point rep: "
<< f_ms.count() << '\n';
}Possible output:
Running some timed piece of code... Timing stats: Time in milliseconds, using default rep: 2 Time in milliseconds, using floating point rep: 2.57307
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