std::packaged_task<R(Args...)>::reset (3) - Linux Manuals

std::packaged_task<R(Args...)>::reset: std::packaged_task<R(Args...)>::reset

NAME

std::packaged_task<R(Args...)>::reset - std::packaged_task<R(Args...)>::reset

Synopsis

void reset(); (since C++11)

Resets the state abandoning the results of previous executions. New shared state is constructed.
Equivalent to *this = packaged_task(std::move(f)), where f is the stored task.

Parameters

(none)

Return value

(none)

Exceptions

* std::future_error if *this has no shared state. The error condition is set to no_state.
* std::bad_alloc if there was not enough memory for a new shared state.
* any exception thrown by the move_constructor of the new packaged_task

Example

// Run this code

  #include <iostream>
  #include <cmath>
  #include <thread>
  #include <future>

  int main()
  {
      std::packaged_task<int(int,int)> task([](int a, int b) {
          return std::pow(a, b);
      });
      std::future<int> result = task.get_future();
      task(2, 9);
      std::cout << "2^9 = " << result.get() << '\n';

      task.reset();
      result = task.get_future();
      std::thread task_td(std::move(task), 2, 10);
      task_td.join();
      std::cout << "2^10 = " << result.get() << '\n';
  }

Output:

  2^9 = 512
  2^10 = 1024