Using Standard Smart Pointers

C++ emphasizes programming with values. By default, your code uses objects, not indirections (references and pointers) to objects. Indirect access to objects is, of course, allowed, and rare is the program that never uses such semantics, but it is an opt-in and requires additional syntax. Chapter 4 explored the association of resource management with object lifetime through destructors and the RAII idiom, demonstrating one of C++’s main strengths in that essentially all resources (including memory) can be handled implicitly through the very mechanics of the language.

C++ allows the use of raw pointers in code but does not actively encourage it. Quite the contrary, in fact – raw pointers are a low-level facility, extremely efficient but easy to misuse, and for which it is not easy to infer responsibility about the pointee directly from the source code. Starting with the (now-removed) auto_ptr<T> facility of decades past, there has...