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| // future example #include <iostream> // std::cout #include <future> // std::async, std::future #include <chrono> // std::chrono::milliseconds // a non-optimized way of checking for prime numbers: bool is_prime (int x) { for (int i=2; i<x; ++i) if (x%i==0) return false; return true; } int main () { // call function asynchronously: std::future<bool> fut = std::async (is_prime,444444443); // do something while waiting for function to set future: std::cout << "checking, please wait"; std::chrono::milliseconds span (100); while (fut.wait_for(span)==std::future_status::timeout) std::cout << '.' << std::flush; bool x = fut.get(); // retrieve return value std::cout << "\n444444443 " << (x?"is":"is not") << " prime.\n"; return 0; }
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