C++ High Performance

Weak pointer

Weak ownership doesn't keep any objects alive; it only allows us to use an object if someone else owns it. Why would you want such a fuzzy ownership as weak ownership? One common reason for using a weak pointer is to break a reference cycle. A reference cycle occurs when two or more objects refer to each other using shared pointers. Even if all external std::shared_ptr constructors are gone, the objects are kept alive by referring to themselves.

Why not just use a raw pointer? Isn't the weak pointer exactly what a raw pointer already is? Not at all. A weak pointer is safe to use since we cannot reference the object unless it actually exists, which is not the case with a dangling raw pointer. An example will clarify this:

auto ...