Explain what happens inside when using the std::move function in C++

The std::move function in C++ does not move an object by itself. It merely casts the object passed to it into an rvalue reference, enabling move semantics.

Inside std::move, there is a simple type cast:

template <typename T>
typename std::remove_reference<T>::type&& move(T&& t) {
    return static_cast<typename std::remove_reference<T>::type&&>(t);
}

This means that std::move informs the compiler that the object t can be treated as a temporary (rvalue), and its resources can be "moved" (for example, in a move constructor or move assignment operator).

Example:

std::string s1 = "Hello";
std::string s2 = std::move(s1); // s1 is now in a state suitable for moving

Here, std::move does not copy or move data, it simply changes the value category, allowing the move constructor to be invoked.