func main() {
var L *lua.State
L = lua.NewState()
L.OpenLibs()
rawptr := L.NewUserdata(uintptr(unsafe.Sizeof(Userdata{})))
var ptr *Userdata
ptr = (*Userdata)(rawptr)
ptr.a = 2
ptr.b = 3
fmt.Println(ptr)
rawptr2 := L.ToUserdata(-1)
ptr2 := (*Userdata)(rawptr2)
fmt.Println(ptr2)
}