Function template is

Function template is_upper

boost::text::v1::is_upper

// In header: <boost/text/case_mapping.hpp>


template<code_point_range R> bool is_upper(R && r);

Returns true if no code point in r would change in a call to to_upper(), and false otherwise.

Returns true if no grapheme in r would change in a call to to_upper(), and false otherwise.