std::packaged_task::reset - cppreference.com

##### cppreference.com

##### Search

Create account

##### Namespaces

- Page
- Discussion

##### Variants

##### Views

- View
- Edit
- History

##### Actions

# std::packaged_task::reset

From cppreference.com
< cpp‎ | thread‎ | packaged task

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.

### [edit] Parameters

(none)

### [edit] Return value

(none)

### [edit] 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`

### [edit] 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

Retrieved from "http://en.cppreference.com/mwiki/index.php?title=cpp/thread/packaged_task/reset&oldid=69985"