我怎么知道是什么使一个不完整的类型不完整的错误:一个指针到一个不完整类型的算术?

I have tried to define my own PointT type to give me XYZRGBA and intensity values in a single point. I tried to follow the conventions laid out in this article on the point cloud library website: I have tried to define my own PointT type to gi