Mastering the C++17 STL

The origins of smart pointers

Raw pointers have many uses in C:

• As a cheap, non-copying view of an object owned by the caller
• As a way for the callee to modify an object owned by the caller
• As one-half of a pointer/length pair, used for arrays
• As an optional argument (either a valid pointer or null)
• As a way to manage memory on the heap

In C++, we have native references (const Foo& and Foo&) to handle the first two bullets; plus, move semantics makes it cheap for a callee to take and pass back a complex object by value in most cases, thus completely avoiding aliasing. In C++17 we can use std::string_view to address some of the first and third bullet. And we've just seen in Chapter 5, Vocabulary Types, that passing an optional<T>--or perhaps ...