// In header: <boost/log/utility/setup/from_settings.hpp>
template<typename CharT> 
struct sink_factory {
  // types
  typedef CharT                               char_type;         // Character type. 
  typedef std::basic_string< char_type >      string_type;       // String type. 
  typedef basic_settings_section< char_type > settings_section;  // Settings section type. 
  // construct/copy/destruct
  sink_factory() = default;
  sink_factory(sink_factory const &) = delete;
  sink_factory & operator=(sink_factory const &) = delete;
  ~sink_factory();
  // public member functions
  virtual shared_ptr< sinks::sink > create_sink(settings_section const &) = 0;
};