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std::packaged_task::packaged_task

From cppreference.com
packaged_task()
(1)
template <class F>
explicit packaged_task(F&& f)
(2)
template <class F, class Allocator>
explicit packaged_task(std::allocator_arg_t, const Allocator& a, F&& f)
(3)
packaged_task(const packaged_task&) = delete
(4)
packaged_task(packaged_task&& rhs)
(5)
1) Constructs a std::packaged_task object with no task and no shared state.
2) Constructs a std::packaged_task object with a shared state and a copy of the task, initialized with std::forward<F>(f).
3) Constructs a std::packaged_task object with a shared state and a copy of the task, initialized with std::forward<F>(f). Uses the provided allocator to allocate memory necessary to store the task.
4) The copy constructor is deleted, std::packaged_task is move-only.

Note: C++11 does not specify const here, this is the defect 2067.

5) Constructs a std::packaged_task with the shared state and task formerly owned by rhs, leaving rhs with no shared state and a moved-from task.

[edit] Parameters

f - the callable target (function, member function, lambda-expression, functor) to execute
a - the allocator to use when storing the task
rhs - the std::packaged_task to move from

[edit] Exceptions

1)
noexcept specification:  
noexcept
  (since C++11)

3-4) Any exceptions thrown by copy/move constructor of f and possiblly std::bad_alloc if the allocation fails.

5)
noexcept specification:  
noexcept
  (since C++11)

[edit] Example