I only instantiated the templates currently using the C++ wrappers in the code base. We can add to this list as more are required. It would also be possible to make ORB_DEFINE do this automatically, but this could lead to instantiated templates that we never use. If you use a new template that isn't listed you will get a link error that should make it obvious you need to add the template instantiation to the uORB library. We could also typedef the currently available instantiated templates as Subscription_parameter_update etc if this would be helpful.