Singleton in C++

Note:

• This solution is not thread-safe in C++ 98/03.

   // Header:
   #include <iostream>

   class Singleton
   {
       /*
           Implementation notes:
               This is thread-safe as of C++ 11/17/..
               This is NOT thread-safe in C++ 98/03
       */

       public:
           // Public-facing methods:

           static void EnableLogging(const bool state)
           {
               Singleton& instance = GetInstance();
               instance.logEnabled = state;
           };

           static void LogMessage(const char* message)
           {
               Singleton& instance = GetInstance();
               if(instance.logEnabled)
               {
                   std::cout << message << std::endl;
               }
           };

       private:
           // Private constructor:
           Singleton()
               : logEnabled(true)
           { };

           // Unlike other languages, we can declare it static
           // Makes instancing much nicer for us.
           static Singleton& GetInstance()
           {
               static Singleton instance;
               return instance;
           }

       public:
           // We don't want these to be usable:
           Singleton(const Singleton&) = delete;
           Singleton& operator=(const Singleton&) = delete;

       private:
           // Instance data:
           bool logEnabled;
   };