> var currentPtr = > cast[LPLOCALGROUP_MEMBERS_INFO_2](https://forum.nim-lang.org/bufptr)
On that line you declare that currentPtr is of type `LPLOCALGROUP_MEMBERS_INFO_2` through (unsafe) casting. If you want to use the `[]` operator on the type it needs to be defined. If you want a pointer to multiple element of the type you should use `ptr UncheckedArray[T]` instead of `ptr T`.
