explicit basic_ostringstream(ios_base::openmode which);
explicit basic_ostringstream(
const basic_string<charT, traits, Allocator>& s,
ios_base::openmode which = ios_base::out);
basic_ostringstream(ios_base::openmode which, const Allocator& a);
explicit basic_ostringstream(
basic_string<charT, traits, Allocator>&& s,
ios_base::openmode which = ios_base::out);
template<class SAlloc>
basic_ostringstream(
const basic_string<charT, traits, SAlloc>& s,
ios_base::openmode which, const Allocator& a);
template<class SAlloc>
explicit basic_ostringstream(
const basic_string<charT, traits, SAlloc>& s,
ios_base::openmode which = ios_base::out);
basic_ostringstream(basic_ostringstream&& rhs);