[Pharo-project] NativeBoost callbacks: double return values?

Sig, Something that I would very much like to go on not really understanding<g> is that complexity of returning a double, and its further impact on callbacks. Aside from the usual myriad uses, my biggest interest in callbacks is for numerical analysis where double return values are very common. Is that something that you can make work by near magic? I don't really care if they require special handling, but it would be very nice if they are at least not very difficult to set up. Bill