The larger a program the greater the chances are you could run into name collisions with file locals when your program is linked. Functions or variables that are declared in a source file and are supposed to be local to the translation unit may collide with other similar functions or variables declared in another translation unit. That is because all symbols that are not declared static have external linkage and their names must be unique throughout the program. The typical C solution for this problem is to declare those symbols static, changing their linkage from external to internal and therefore making them local to a translation unit. In this recipe, we will look at the C++ solution for this problem.