C++ Primer Plus

Traditional C++ Namespaces

Before looking at the new namespace facilities in C++, let’s review the namespace properties that already exist in C++ and introduce some terminology. This can help make the idea of namespaces seem more familiar.

One term you need to be aware of is declarative region. A declarative region is a region in which declarations can be made. For example, you can declare a global variable outside any function. The declarative region for that variable is the file in which it is declared. If you declare a variable inside a function, its declarative region is the innermost block in which it is declared.

A second term you need to be aware of is potential scope. The potential scope for a variable begins at its point of declaration ...