std::chrono::treat_as_floating_point
From cppreference.com
C++
Feature test macros (C++20)
Concepts library (C++20)
Metaprogramming library (C++11)
Ranges library (C++20)
Filesystem library (C++17)
Concurrency support library (C++11)
Execution control library (C++26)
Date and time library
(C++11)
(C++20)
(C++20)
(C++11)
(C++11)
(C++11)
(C++20)
(C++20)
(C++20)
(C++11)
(C++20)
(C++20)
(C++20)
(C++20)(C++20)
(C++20)(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)(C++20)
(C++20)
(C++20)
(C++20)
(C++20)(C++20)(C++20)(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
std::chrono::duration
Member functions
Non-member functions
(until C++20)(C++20)
(C++20)
(C++17)
(C++17)
(C++17)
(C++17)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++20)
Helper classes
Defined in header
<chrono>
template< class Rep >
struct treat_as_floating_point : std::is_floating_point <Rep> {};
(since C++11)
struct treat_as_floating_point : std::is_floating_point <Rep> {};
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 is true.
[edit] Helper variable template
template< class Rep >
constexpr bool treat_as_floating_point_v = treat_as_floating_point<Rep>::value;
(since C++17)
constexpr bool treat_as_floating_point_v = treat_as_floating_point<Rep>::value;
[edit] Specializations
std::chrono::treat_as_floating_point may be specialized for program-defined types.
[edit] Example
Run this code
#include <chrono> #include <iostream> #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