Hands-On Design Patterns with C++

Meyers' Singleton

This implementation is named after its inventor, Scott Meyers. If the main problem with the static singleton is that it can be initialized later than its first use, then the solution must be to initialize the singleton when it is needed for the first time:

class Singleton {    public:    static Singleton&amp; instance() {        static Singleton inst;        return inst;    }    int&amp; get() { return value_; }    private:    Singleton() : value_(0) {        std::cout << "Singleton::Singleton()" << std::endl;    }    Singleton(const Singleton&amp;) = delete;    Singleton&amp; operator=(const Singleton&amp;) = delete;    ~Singleton() {        std::cout << "Singleton::~Singleton()" << std::endl;    }

    private:    int value_;};

The Meyers' Singleton has a private constructor, so it cannot ...