The get member function waits (by calling wait ()) until the shared state is ready, then retrieves the value stored in the shared state (if any). The creator of the asynchronous operation can then use a variety of. This function may block for longer than timeout_duration due to scheduling or resource contention delays. The behavior is undefined if valid () is false before the call to this function, or clock does not meet the clock requirements. You can use annotations because annotations have existed since python 3.0, you don't need to import anything from __future__ to use them what you're importing if you do from __future__ import annotations is postponed annotations.
Blocks until the result becomes available. The first part is easy: The class template std::future provides a mechanism to access the result of asynchronous operations: Checks if the future refers to a shared state. If the future is the result of a call to async that used lazy evaluation, this function returns immediately without waiting.
The get member function waits (by calling wait ()) until the shared state is ready, then retrieves the value stored in the shared state (if any). The creator of the asynchronous operation can then use a variety of. This function may block for longer than timeout_duration due to scheduling or resource contention delays. The behavior is undefined if valid ().
Blocks until the result becomes available. The first part is easy: The class template std::future provides a mechanism to access the result of asynchronous operations: Checks if the future refers to a shared state. If the future is the result of a call to async that used lazy evaluation, this function returns immediately without waiting.
// functions to check state bool valid () const noexcept; If valid () is false before the call to this function, the behavior is undefined. An asynchronous operation (created via std::async, std::packaged_task, or std::promise) can provide a std::future object to the creator of that asynchronous operation. Future (const future &) = delete; Future & operator =(const future &) = delete;
Returns a future object associated with the same shared state as *this. The behavior is undefined if valid() == false before the call to this function. Right after calling this function, valid () is false. The postponed annotations feature means that you can use something in an annotation even if it hasn't been. Valid() == true after the call.
// retrieving the value /* see description */ get (); An exception is thrown if *this has no shared state or get_future has already been called. Future & operator =(future &&) noexcept; Returned by std::promise::get_future (), std::packaged_task::get_future () or std::async ()) until the first time get () or share () is called. If the future is the result of a.
If valid () is false before the call to this function, the behavior is undefined. An asynchronous operation (created via std::async, std::packaged_task, or std::promise) can provide a std::future object to the creator of that asynchronous operation. Future (const future &) = delete; Future & operator =(const future &) = delete;
The behavior is undefined if valid() == false before the call to this function. Right after calling this function, valid () is false. The postponed annotations feature means that you can use something in an annotation even if it hasn't been. Valid() == true after the call.
An exception is thrown if *this has no shared state or get_future has already been called. Future & operator =(future &&) noexcept; Returned by std::promise::get_future (), std::packaged_task::get_future () or std::async ()) until the first time get () or share () is called. If the future is the result of a call to std::async that used lazy evaluation, this function returns immediately without waiting.
Shared_future share () noexcept; The function template std::async runs the function f asynchronously (potentially in a separate thread which might be a part of a thread pool) and returns a std::future that will eventually hold the result of that function call.