How to make a vec3 pointer in lua?

cocos2d-x Lua
#1

Hi Everyone, I got a lot of warning like this.

Warning: ccui.Widget:hitTest argument 4 is invalid native object(nullptr)

The last arg type is “cocos2d::Vec3*”. How to make a “cocos2d::Vec3*” in lua?

function Widget:hitTest(pos)
    local func = tolua.getcfunction(self, "hitTest")
    func(self, pos, cc.Camera:getDefaultCamera(), nil)
end