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

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

#include <cmath>
#include <future>
#include <iostream>
#include <thread>
 
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';
}

2^9 = 512
2^10 = 1024