您的胶印中有错字

offsets[3] = offsetof(Vector3d, z);

应该是offset[2].我想这就是解决bcast问题的全部方法.

Should be offset[2] instead. I guess that and fixing the bcast problem is all it takes.

offsetof函数的结果又是什么?如何运作?

Also what is the result of your offsetof function? How does it work?