code: func getMemifError(code int) error {
  	if code == 0 {
  		return nil /* success */
  	}
  	err, known := errorRegistry[code]
  	if !known {
  		return ErrUnknown
  	}
  	return err
  }
docs: // getMemifError returns the MemifError associated with the given C-libmemif
  // error code.