Capture and move a unique_ptr in a c++14 lambda expression

The operator () of a lambda is const by default, and you can’t move from a const object.

Declare it mutable if you want to modify the captured variables.

auto lambda = [ capturedStr = std::move(str) ] () mutable {
//                                             ^^^^^^^^^^
    cout << *capturedStr.get() << endl;
    auto str2 = std::move(capturedStr);
};