Low-level types

Another category of components provides fundamental, low-level types. These are low-level in the sense that you would be more likely to use them to build other components than to use them directly in an application. Pool(C++), Objection(C++), and the ``pointer'' classes provided by List(C++) and Set(C++) fall into this category. For example, one of the facilities of the Pool(C++) component, class Pool, manages fixed-size chunks of storage very efficiently. It is useful in building other classes that allocate and free many instances of some fixed-size type T. As a proof of concept, several of the components in C++ Standard Components use Pools for their internal storage management. List(C++), for example, uses Pools to allocate List nodes.