std::future::future

(1) default constructor

Constructs an empty future: The object has no shared state, and thus is not valid, but it can be move-assigned another future value.

(2) copy constructor [deleted]

future objects cannot be copied (see shared_future for a copyable future class).

(3) move constructor

The constructed object acquires the shared state of x (if any).
x is left with no shared state (it is no longer valid).

Parameters

x

Another future object of the same type (with the same template parameter, T).

Example

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// future::future
#include <iostream>       // std::cout
#include <future>         // std::async, std::future

int get_value() { return 10; }

int main ()
{
  std::future<int> foo;                            // default-constructed
  std::future<int> bar = std::async (get_value);   // move-constructed

  int x = bar.get();

  std::cout << "value: " << x << '\n';

  return 0;
}

value: 10

Data races

Exception safety

See also

future::operator=

Move-assign future (public member function)

future::get

Get value (public member function)