Beginning C++ Programming

Sharing ownership

There are occasions when you will need to share a pointer: you may create several objects and pass a pointer to a single object to each of them so they can call this object. Ordinarily, when an object has a pointer to another object, that pointer represents a resource that should be destroyed during the destruction of the containing object. If a pointer is shared, it means that when one of the objects deletes the pointer, the pointers in all of the other objects will be invalid (this is called a dangling pointer because it no longer points to an object). You need a mechanism where several objects can hold a pointer that will remain valid until all the objects using that pointer have indicated they will no longer need to ...