std::promise<R>::get_future
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std::promise
Member functions
Getting the result
promise::get_future
Setting the result
Non-member Functions
Helper Classes
std::future <R> get_future();
(since C++11)
Returns a future object associated with the same shared state as *this.
An exception is thrown if *this has no shared state or get_future has already been called. To get multiple "pop" ends of the promise-future communication channel, use std::future::share .
Calls to this function do not introduce data races with calls to set_value , set_exception , set_value_at_thread_exit , or set_exception_at_thread_exit (therefore they need not synchronize with each other).
[edit] Parameters
(none)
[edit] Return value
A future referring to the shared state of *this.
[edit] Exceptions
std::future_error on the following conditions:
- *this has no shared state. The error code is set to no_state.
-
get_future()has already been called on a promise with the same shared state as *this. The error code is set to future_already_retrieved.