boost::text::v1::normalize_append
// In header: <boost/text/normalize_string.hpp> template<nf Normalization, code_point_iter I, std::sentinel_for< I > S, utf_string String> void normalize_append(I first, S last, String & s);
Appends [first, last) in normalization form Normalization to s. The output is UTF-8 if sizeof(*s.begin()) == 1, and UTF-16 otherwise.
[first, last)
Normalization
s
sizeof(*s.begin()) == 1