cpp exception question

gistfile1.txt

    std::stringstream errorMessage;
    errorMessage << "out of range access"
      << "tried to access " << x << ", " << y << ", " << z << ", " << w
      << std::endl << "but image dimensions are: " << width_ << ", " << height_ << ", " << depth_ << ", " << spektrum_
      << std::endl;
    throw std::out_of_range(errorMessage.str());