protected:
basic_ios();

public:
explicit basic_ios( std::basic_streambuf<CharT,Traits>* sb );

private:
basic_ios(const basic_ios&);

public:
basic_ios(const basic_ios& ) = delete;

1) Default constructor. The internal state is not initialized. init() must be called before the first use of the object or before destructor, otherwise the behavior is undefined.

2) Initializes the internal state by calling init(sb). The associated stream buffer is set to sb.

3) The copy constructor was declared private: and not defined until C++11 and is declared as deleted in C++11: I/O streams are not CopyConstructible.