Singletons

singleton.h

// Very bad because the destruction order is not specified.
// From experience, these are one of the hardest to debug bugs.
template <class T>
T BadSingleton() {
  static T t;
  return t;
}

// Better. It is NOT a leak because the compiler will clear it after the shutdown.
// Downside -- destuctors are not called. But you should never do complicated
// things in destructors.
template <class T>
T BetterSingleton() {
  static T* t = new T();
  return *t;
}