OfxInteractiveVariable is a project mainly written in C++ and C, it's free.
Wrappers for simple variables (e.g. float, int, etc) that automatically register themselves onto a stack of interactive variables. These can then be edited globally. (So far not useful)
ofxInteractiveVariable, copyright Kimchi and Chips 2011
Wrappers for simple vars (e.g. float, int, etc) to register onto global 'interactive variable' dictionary for global editing.