std::shared_future::operator= (3) Linux Manual Page

std::shared_future<T>::operator= – std::shared_future<T>::operator=

Synopsis

shared_future &operator=(const shared_future &other);
(since C++ 11)(1)(until C++ 17)

    shared_future &
    operator=(const shared_future &other) noexcept;
(since C++ 17)

    shared_future &
    operator=(shared_future &&other) noexcept;
(2)(since C++ 11)

Assigns the contents of another shared_future.
1) Releases any shared state and assigns the contents of other to *this. After the assignment, this->valid() == other.valid().
2) Releases any shared state and move-assigns the contents of other to *this. After the assignment, other.valid() == false and this->valid() will yield the same value as other.valid() before the assignment.

Parameters

other – a std::shared_future that will transfer state to *this

Return value

*this