Return a bsl::string having the value of the concatenation of the strings referred to by the specified lhs and rhs values.
Declared in <bslstl_stringref.h>
template<class CHAR_TYPE>
bsl::basic_string<CHAR_TYPE>
operator+(
StringRefImp<CHAR_TYPE> const& lhs,
StringRefImp<CHAR_TYPE> const& rhs);