C++ Singletons which don't leak

Singleton.h

class Singleton {
public:
    // Lazily get reference to a static instance of Singleton.
    // The benifit of the following inplementation:
    //  * It lazily creates a Singleton.
    //  * It creates the Singleton on the global stack, so when the program ends
    //    the Singleton is automatically deallocated and it's deconstructor is invoked.
    static Singleton& getInstance() {
        // The following line (starting with `static`) only executes once, 
        // no matter how many times this function executes.
        static Singleton singleton; 
        return shelter;
    }
    
    // The following line explicitly forbids the compiler from using a copy constructor. (C++11)
    Singleton(const Singleton&) = delete;
  
    ~Singleton();

private:
    // Keep the constructor private so that the only way to create the Singleton
    // is through the `getInstance()` method.
    Singleton();
    
};