void wait() const; | (since C++11) |
Blocks until the result becomes available. valid() == true after the call.
The behavior is undefined if valid()== false before the call to this function.
(none).
(none).
(none).
The implementations are encouraged to detect the case when valid == false before the call and throw a std::future_error with an error condition of std::future_errc::no_state.
#include <iostream>
#include <future>
#include <thread>
int fib(int n)
{
if (n < 3) return 1;
else return fib(n-1) + fib(n-2);
}
int main()
{
std::future<int> f1 = std::async(std::launch::async, [](){
return fib(20);
});
std::future<int> f2 = std::async(std::launch::async, [](){
return fib(25);
});
std::cout << "waiting...\n";
f1.wait();
f2.wait();
std::cout << "f1: " << f1.get() << '\n';
std::cout << "f2: " << f2.get() << '\n';
}Output:
waiting... f1: 6765 f2: 75025
| waits for the result, returns if it is not available for the specified timeout duration (public member function) |
|
| waits for the result, returns if it is not available until specified time point has been reached (public member function) |
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