C++

13.2    Anonymous Namespace

You can also define a namespace without its own identifier. This then has a special meaning. For the purposes of the next listing, assume that you have several files here.

// https://godbolt.org/z/e3d55zvT8// modul.hpp#include <string>#include <iostream>namespace plant {    class Tree {        std::string name_;    public:        explicit Tree(const std::string_view name);        void print(std::ostream& os) const;    };    std::ostream& operator<<(std::ostream& os, const Tree& arg);}// modul.cpp#include "module.hpp"namespace {  // anonymous namespace    std::string PREFIX = "TREE:";    void printInfo(std::ostream& os) {        os << "Author: Torsten T. Will\n";    }}bool debug = false;  // global, no namespacenamespace plant {    Tree::Tree(const std::string_view name) ...