message: aded invalid operation failure code
diff: @@ -25,6 +25,7 @@ enum NrtResultKind {
  NRT_FAILURE_INITIALISATION_FAILURE = -10,
  NRT_FAILURE_NOT_INITIALISED = -11,
  NRT_FAILURE_FUNCTION_NOT_FOUND = -12,
  + NRT_FAILURE_INVALID_OPERATION = -13
  };
  typedef int32_t NrtBool;
  