C Programming Question

[tophq]

Ok, before I begin let me start off by saying that I have checked around to find the answer ot my question and I have not found a suitable answer, this may be due to the lack of my attention span though...lol. Ok my problem is I'm trying to use the trim wheel on the joystick to set the robot into autonomous mode. Now I first added the

unsigned char wheel_right

to the user_routines.h header file and I still keep getting errors. It says "wheel_right is not defined" when I try to build it. I also tried adding the code directly before the function but when I do that it says I have multiple definitions and it still won't build. Where and how do I need to define and declare my variables. Any help would be greatly appreciated.