extern void Volume_Up_Marktask_IR(void); extern void Volume_Down_Aiwa(void); extern void Volume_Down_Marktask_IR(void); extern void Page_Down_Marktask_IR(void); ..\MAINS.C(476): warning C206: 'Page_Down_MarkTask_IR': missing function-prototype ..\MAINS.C(486): warning C206: 'Volume_Up_MarkTask_IR': missing function-prototype ..\MAINS.C(497): warning C206: 'Volume_Down_MarkTask_IR': missing function-prototype Could be just a typo in your post here, but the capitalisation in your extern declarations doesn't match the names shown in the warnings... But IDE uvision2 build succesfully project dispite of existing wrong functions calls.
But IDE uvision2 build succesfully project dispite of existing wrong functions calls.