explicit basic_stringstream(
ios_base::openmode which = ios_base::out|ios_base::in);
Effects: Constructs an object of class basic_stringstream<charT,traits>, initializing the base class with basic_iostream(&sb) and initializing sb with basic_stringbuf<charT,traits,Allocator>(which).
explicit basic_stringstream(
const basic_string<charT,traits,Allocator>& str,
ios_base::openmode which = ios_base::out|ios_base::in);
Effects: Constructs an object of class basic_stringstream<charT, traits>, initializing the base class with basic_iostream(&sb) and initializing sb with basic_stringbuf<charT, traits, Allocator>(str, which).
basic_stringstream(basic_stringstream&& rhs);
Effects: Move constructs from the rvalue rhs. This is accomplished by move constructing the base class, and the contained basic_stringbuf. Next basic_istream<charT,traits>::set_rdbuf(&sb) is called to install the contained basic_stringbuf.