Hi guy's I'm back with new questions.. :) I recently tried to add a ISR into a C++ file.. So thats working right now, but now I want to try something like that: #define TIMER(node_instance) extern "C" {void TIM2_IRQHandler() node_instance.TimerInterrupt();}} I want to create a Macro for the TIM2 IRQ. So if an Timer Interrupt occurs it should call the node_instance.TimerInterrupt() function. But somehow it's not working, that means that the node_instance.TimerInterrupt() is not getting called.. I don't have access to the uC. So I can't do any kind of testing right now. But maybe I dont have it in the right order?! Or maybe it should be like: #define extern "C" {void TIM2_IRQHandler()}(node_instance.TimerInterrupt()) But I think this is also wrong.. Any ideas? Thx Kenan p.s. I'm working with codesourcery and the stm32f103