// In header: <boost/log/sinks/text_file_backend.hpp>

class rotation_at_time_point {
public:
  // types
  typedef bool result_type;
  // construct/copy/destruct
  explicit rotation_at_time_point(unsigned char, unsigned char, unsigned char);
  explicit rotation_at_time_point(date_time::weekdays, unsigned char = 0, 
                                  unsigned char = 0, unsigned char = 0);
  explicit rotation_at_time_point(gregorian::greg_day, unsigned char = 0, 
                                  unsigned char = 0, unsigned char = 0);
  // public member functions
  bool operator()() const;
};