[re.regex.nonmemb]
28 Text processing library [text]
28.6 Regular expressions library [re]
28.6.7 Class template basic_regex [re.regex]
28.6.7.7 Non-member functions [re.regex.nonmemb]
template<class charT, class traits>
void swap(basic_regex<charT, traits>& lhs, basic_regex<charT, traits>& rhs);