# std::shared_future<T>::wait_until

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< cpp‎ | thread‎ | shared future

template< class Clock, class Duration > std::future_status wait_until( const std::chrono::time_point <Clock,Duration>& timeout_time ) const; |  | (since C++11)

`wait_until` waits for a result to become available. It blocks until specified `timeout_time` has been reached or the result becomes available, whichever comes first. The return value indicates why `wait_until` returned.

The behavior is undefined if valid() == false before the call to this function.

### Parameters

timeout_time | - | maximum time point to block until

### Return value

Constant | Explanation
`future_status::deferred` | The function to calculate the result has not been started yet
`future_status::ready` | The result is ready
`future_status::timeout` | The timeout has expired

### Exceptions

Any exception thrown by clock, time_point, or duration during the execution (clocks, time points, and durations provided by the standard library never throw)

### Notes

The implementations are encouraged to detect the case when valid == false before the call and throw a future_error with an error condition of future_errc::no_state.

The clock tied to `timeout_time` is used, which 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 convert `timeout_time` from `Clock` to std::chrono::system_clock and delegate to POSIX pthread_cond_timedwait so that the wait honors ajustments to the system clock, but not to the the user-provided `Clock`. In any case, the function also may wait for longer than until after `timeout_time` has been reached due to scheduling or resource contention delays.

### Example

| This section is incomplete Reason: no example

### See also

wait | waits for the result to become available (public member function)
wait_for | waits for the result, returns if it is not available for the specified timeout duration (public member function)

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