C中多个函数的回调

Question

I'm trying to write code in C (for embedded application), in which there would be event callback (caused by pressing a button) calling different functions, depending on GUI screen that is currently displayed.
Ideally I would like to "define" function like: keyXPressed() many times and programming different actions in different parts of the code (like on Screen1 do this and on Screen2 do that), so that single callback would always refer to one that is currently on. I know that multiple definitions of the functions are probably not the way and presumably some object-oriented techniques will be involved.
What are the ways of achieving such functionality in simple and elegant manner?

Answer 1

Use a function pointer.

void (*keyPressed)(screen *);

void keyXPressed(screen *s) {
    // code here
}
void keyYPressed(screen *s) {
    // code here
}

Then you can assign keyPressed = keyXPressed; or keyPressed = keyYPressed; , and call keyPressed(screen1);