warning: control reaches end of non-void function in recursive function

Question

I am getting warning: control reaches end of non-void function.

I have a recursive function that looks like this:

unsigned long FUNCTION (....) {

    if (something) {
        return 1;
    }
    else if (something2) {

        if(thing) {
            FUNCTION(....);
        }
        else
            return 0;
    }
    else {
        return 0;
    }
}

I can't just put return 0; at the end of the function because it ends up making my program do what I don't want it to. How do I make the warning go away?

Answer 1

The branch calling FUNCTION(...) doesn't return anything. As a result, if this branch is taken your function has undefined behavior. What needs to be returned can't be determined from your code: you'll have to come up with that.

Note that FUNCTION normally indicates that the name is a macro: there are a few conventions how things are named to avoid confusion. You can call your functions with all uppercase letters but it may not be a good idea.