C++ Patterns: The Badge

An outsider class or function can also be declared as a friend. Let’s use an example from the (virtual file system) class in Serenity:

These functions are called by all objects when they are constructed and destroyed respectively. A common technique for preventing others from accessing these functions would be making them private and adding as a friend of :

This prevents outsiders except from calling those functions, but it also means that now has full access to the private parts of which is not great.

Source: awesomekling.github.io