Chapter 3, Memory and Ownership

1. Clear memory ownership, and by extension, resource ownership, is one of the key attributes of a good design. With clear ownership, resources are certain to be created and made available in time for when they are needed, maintained while they are in use, and released/cleaned up when no longer needed.
2. Resource leaks, including memory leaks; dangling handles (resource handles, such as pointers, references, or iterators, pointing to resources that do not exist); multiple attempts to release the same resource; multiple attempts to construct the same resource.
3. Non-ownership, exclusive ownership, shared ownership, as well as conversion between different types of ownership and transfer of ownership.
4. Ownership-agnostic functions and classes should refer to objects by raw pointers and references if the corresponding ownership is handled through owning pointers. If the objects are owned by rich pointers or containers, the problem becomes more difficult...