std::basic_iostream<CharT,Traits>:: basic_iostream

1) Initializes with streambuf sb . The base classes are initialized as basic_istream < CharT,Traits > ( sb ) and basic_ostream < CharT,Traits > ( sb ) . After the call rdbuf ( ) == sb and gcount ( ) == 0 .

2) Copy construction is not allowed.

3) Move constructor: move-constructs the first base class basic_istream as basic_istream < CharT,Traits > ( std :: move ( rhs ) ) ; , which in turn move-constructs and initializes the virtual base std::basic_ios . The initialization of the other base, basic_ostream , is implementation-defined (e.g., a protected default constructor may be added to std::basic_ostream , which does nothing) because move-construction cannot use rhs twice. This move constructor is protected: it is called by the move constructors of the derived stream classes std::basic_fstream and std::basic_stringstream before they move-construct and associate the stream buffer.