Code can always be called outside of that scope just by returning function pointers or closures. The point is not to restrict calling that code, but to restrict

Code can always be called outside of that scope just by returning function pointers or closures. The point is not to restrict calling that code, but to restrict the ability to refer to that piece of code by name. As mentioned by others, C++ has lambdas. Even if you don't use lambdas, people used to achieve the same effect by using plenty of private functions inside classes, even though the class might have zero variables and simply holds functions. In even older C code, people are used to making one separate .c file for each public function and then define plenty of static functions within each file.