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std::promise::get_future(3) C++ Standard Libary std::promise::get_future(3)


std::promise::get_future - std::promise::get_future


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

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 (but they
need not synchronize with each other).



Return value

A future referring to the shared state of *this


std::future_error on the following conditions:

* *this has no shared state. The error category is set to no_state.

* get_future() has already been called on a promise with the same shared state as
*this. The error category is set to future_already_retrieved.