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| Member functions | ||||
| Getting the result | ||||
| State | ||||
shared_future::wait_until |
template<class Clock,class Duration> std::future_status wait_until(conststd::chrono::time_point<Clock,Duration>& timeout_time)const; | (since C++11) | |
wait_until waits for a result to become available. It blocks until specifiedtimeout_time has been reached or the result becomes available, whichever comes first. The return value indicates whywait_until returned.
If the future is the result of a call toasync that used lazy evaluation, this function returns immediately without waiting.
The behavior is undefined ifvalid() isfalse before the call to this function, orClock does not meet theClock requirements.The programs is ill-formed ifstd::chrono::is_clock_v<Clock> isfalse.(since C++20)
Contents |
| timeout_time | - | maximum time point to block until |
| Constant | Explanation |
| future_status::deferred | The shared state contains a deferred function using lazy evaluation, so the result will be computed only when explicitly requested |
| future_status::ready | The result is ready |
| future_status::timeout | The timeout has expired |
Any exception thrown by clock, time_point, or duration during the execution (clocks, time points, and durations provided by the standard library never throw).
The implementations are encouraged to detect the case whenvalid()==false before the call and throw astd::future_error with an error condition offuture_errc::no_state.
The standard recommends that the clock tied totimeout_time be used to measure time; that clock is not required to be a monotonic clock. There are no guarantees regarding the behavior of this function if the clock is adjusted discontinuously, but the existing implementations converttimeout_time fromClock tostd::chrono::system_clock and delegate to POSIXpthread_cond_timedwait so that the wait honors adjustments to the system clock, but not to the user-providedClock. In any case, the function also may wait for longer than until aftertimeout_time has been reached due to scheduling or resource contention delays.
| This section is incomplete Reason: no example |
| waits for the result to become available (public member function)[edit] | |
| waits for the result, returns if it is not available for the specified timeout duration (public member function)[edit] |
