I'm seeking some support for Part 5 of my FFI tutorial http://blog.openinworld.com/2016/09/pharo-libclang-ffi-part-5-client-data-an... where I'm trying to replicate some C code where: * client_data is a void pointer, and an argument to a callout function * a reference to some data (an int, or a struct) is passed to the callout function as the client_data * the callout function passes that same client_data to a callback function which casts the client-data to the required type How can I replicate that with UFFI? The key thing is that *any* type can be passed via client_data. So for a normal Pharo object defined like... Object subclass: MyObject instanceVariables: 'x y' myobject := MyObject new x:3 y:4. I want to pass a reference to myobject to the callout, and in the callback dereference client_data to get myobject that I can operate on normally. Is this possible with current infrastructure, or would it need something new like FFIInternalPinnedReference to wrap myobject for the callout and unwrap it in the callback? cheers -ben