C++ and the Perils of Double-Checked Locking: Part II

class Singleton {
public:
   static Singleton* instance();  
   ...
private:
   static Singleton* volatile pInstance;
   int x;
   ...
};
Singleton* Singleton::instance()
{
   if (pInstance == 0) {
      Lock lock;
      if (pInstance == 0) {
         Singleton* volatile temp =
         static_cast<Singleton*>(operator new(sizeof(Singleton)));
            static_cast<volatile int&>(temp->x) = 5;
            pInstance = temp;
      }
   }
}

Example 11: Inlining a function in Singleton.