basic_streambuf();
Remarks: Once the getloc() member is initialized, results of calling locale member functions, and of members of facets so obtained, can safely be cached until the next time the member imbue is called.
basic_streambuf(const basic_streambuf& rhs);
~basic_streambuf();
The default constructor is protected for class basic_streambuf to assure that only objects for classes derived from this class may be constructed.