protected: ios_base ();
  private: ios_base (const ios_base&);

Construct object

ios_base objects have indeterminate values on construction. Each ios_base base object shall be initialized with ios::init.

Because the constructors are protected and private, this class cannot be directly instantiated: only objects of derived classes can be created.

ios_base also declares an assignment operator member function. Like the copy constructor, this function is also private:

private:
  ios_base (const ios_base&);
  ios_base& operator= (const ios_base&);

This effectively also prevents ios_base objects to be copied.