Review Videos! • clocks, clock_cast, leap_seconds (https://youtu.be/WX3OmVu4lAs) • time_zone and time_zone_link (https://youtu.be/MODhhr7m-5s) • system_clock::now(), file_clock, leap second awareness (https://youtu Plus, the types often end up boiling down to constants anyway!18 Part III: Clocks19 What is a clock? #include #include using namespace std::chrono; class MyClock { public: is_steady = false; static time_point now() {} }; static_assert(is_clock_v); For a type T to qualify as a Clock, it must satisfy each of the following conditions: • The following qualified-ids

in :  std::system_clock: wall clock time from system-wide real-time clock  std::steady_clock: guarantees it never goes backwards  std::high_resolution_clock: has shortest possible tick C++20 adds:  utc_clock, tai_clock, gps_clock, and file_clock  Every clock has a now() method21 Clocks – Examples  Example: // Get current time as a time_point. system_clock::time_point tpoint tpoint { system_clock::now() }; // Or: auto tpoint { system_clock::now() }; // Convert to a time_t. time_t tt { system_clock::to_time_t(tpoint) }; // Convert to local time. tm* t { localtime(&tt) }; // Write

uint64_t CPU_CLOCK_HZ = 400'000'000; // API to implement: std::chrono::nanoseconds elapsed_time(uint64_t num_cpu_ticks); 1 2 3 4 8Example: “CPU ticks” time units constexpr uint64_t CPU_CLOCK_HZ = 400'000'000; nds elapsed_time(uint64_t num_cpu_ticks) { using NS_PER_TICK = std::ratio<1'000'000'000, CPU_CLOCK_HZ>; return std::chrono::nanoseconds{ num_cpu_ticks * NS_PER_TICK::num / NS_PER_TICK::den NS_PER_TICK::den }; } 1 2 3 4 5 6 8.1Example: “CPU ticks” time units constexpr uint64_t CPU_CLOCK_HZ = 400'000'000; // API to implement: std::chrono::nanoseconds elapsed_time(uint64_t num_cpu_ticks); 1 2

it’s actually needed. Creating a Celery instance will only do the following: 1. Create a logical clock instance, used for events. 2. Create the task registry. 3. Set itself as the current app (but not User id used to connect to the broker with. virtual_host Virtual host used. clock Value of the workers logical clock. This is a positive integer and should be increasing every time you receive statistics [https://docs.python.org/dev/library/datetime.html#datetime.timedelta] schedules are scheduled “by the clock.” This means the frequency is rounded to the nearest second, minute, hour or day depending on the

it’s actually needed. Creating a Celery instance will only do the following: 1. Create a logical clock instance, used for events. 2. Create the task registry. 3. Set itself as the current app (but not User id used to connect to the broker with. virtual_host Virtual host used. clock Value of the workers logical clock. This is a positive integer and should be increasing every time you receive statistics [https://docs.python.org/dev/library/datetime.html#datetime.timedelta] schedules are scheduled “by the clock.” This means the frequency is rounded to the nearest second, minute, hour or day depending on the

it’s actually needed. Creating a Celery instance will only do the following: 1. Create a logical clock instance, used for events. 2. Create the task registry. 3. Set itself as the current app (but not User id used to connect to the broker with. virtual_host Virtual host used. clock Value of the workers logical clock. This is a positive integer and should be increasing every time you receive statistics [https://docs.python.org/dev/library/datetime.html#datetime.timedelta] schedules are scheduled “by the clock.” This means the frequency is rounded to the nearest second, minute, hour or day depending on the

it’s actually needed. Creating a Celery instance will only do the following: 1. Create a logical clock instance, used for events. 2. Create the task registry. 3. Set itself as the current app (but not User id used to connect to the broker with. virtual_host Virtual host used. clock Value of the workers logical clock. This is a positive integer and should be increasing every time you receive statistics [https://docs.python.org/dev/library/datetime.html#datetime.timedelta] schedules are scheduled “by the clock.” This means the frequency is rounded to the nearest second, minute, hour or day depending on the

it’s actually needed. Creating a Celery instance will only do the following: 1. Create a logical clock instance, used for events. 2. Create the task registry. 3. Set itself as the current app (but not User id used to connect to the broker with. virtual_host Virtual host used. clock Value of the workers logical clock. This is a positive integer and should be increasing every time you receive statistics [https://docs.python.org/dev/library/datetime.html#datetime.timedelta] schedules are scheduled “by the clock.” This means the frequency is rounded to the nearest second, minute, hour or day depending on the

it’s actually needed. Creating a Celery instance will only do the following: 1. Create a logical clock instance, used for events. 2. Create the task registry. 3. Set itself as the current app (but not User id used to connect to the broker with. virtual_host Virtual host used. clock Value of the workers logical clock. This is a positive integer and should be increasing every time you receive statistics [https://docs.python.org/dev/library/datetime.html#datetime.timedelta] schedules are scheduled “by the clock.” This means the frequency is rounded to the nearest second, minute, hour or day depending on the

(int i { startValue }; i < startValue + numberOfValues; ++i) { time_t t { system_clock::to_time_t(system_clock::now()) }; cout << std::ctime(&t); co_yield i; } } int main() { auto gen 1 week into days62 Calendars & Timezones  New clocks (besides system_clock, steady_clock, high_resolution_clock):  utc_clock: represents Coordinated Universal Time (UTC), measures time since 00:00:00 00:00:00 UTC, Thursday, 1 January 1970, including leap seconds  tai_clock: represents International Atomic Time (TAI), measures time since 00:00:00, 1 January 1958, and was offseted 10 seconds ahead of