The nested class named FProtection prevents the creation of instances by direct calling the constructor.

singleton_using_nested_class.cpp

#include "stdafx.h"


template <typename T>
class TSingleton {
public:
    TSingleton() {}
    ~TSingleton() {
        delete(Instance_);
    }

private:
    static T* Instance_;

protected:
    struct FProtection {};

public:
    static T& GetInstance() {
        if (Instance_ == nullptr) {
            Instance_ = new T(FProtection());
        }
        return *Instance_;
    }

    TSingleton(TSingleton const&) = delete;
    void operator=(TSingleton const&) = delete;
};

template <typename T> T* TSingleton<T>::Instance_;

class Foo : public TSingleton<Foo> {
 public:
  void* GetAddress () {
    return reinterpret_cast<void*>(this);
  }
  Foo (const FProtection&) {}
};

int main() {
  //auto foo = new Foo(Foo::FProtection()); // C2248 compile error
  std::cout << Foo::GetInstance().GetAddress() << std::endl;
  return 0;
}