30 Input/output library [input.output]

30.8 String-based streams [string.streams]

30.8.3 Class template basic_­istringstream [istringstream]

30.8.3.1 basic_­istringstream constructors [istringstream.cons]

explicit basic_istringstream(ios_base::openmode which = ios_base::in);
Effects: Constructs an object of class basic_­istringstream<charT, traits>, initializing the base class with basic_­istream<charT, traits>(&sb) ([istream]) and initializing sb with basic_­stringbuf<charT, traits, Allocator>(which | ios_­base​::​in)) ([stringbuf.cons]).
explicit basic_istringstream( const basic_string<charT, traits, Allocator>& str, ios_base::openmode which = ios_base::in);
Effects: Constructs an object of class basic_­istringstream<charT, traits>, initializing the base class with basic_­istream<charT, traits>(&sb) ([istream]) and initializing sb with basic_­stringbuf<charT, traits, Allocator>(str, which | ios_­base​::​in)) ([stringbuf.cons]).
basic_istringstream(basic_istringstream&& 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.