C++ Virtual function being hidden

I'm having a problem with C++ inheritance.

I have a class hierarchy:

class A {
public:
   virtual void onFoo() {}
   virtual void onFoo(int i) {}
};

class B : public A {
public:
    virtual void onFoo(int i) {}
};

class C : public B {
};


int main() {
    C* c = new C();
    c->onFoo(); //Compile error - doesn't exist
}

My question is: why doesn't this compile? My understanding is that C should inherit both onFoo functions from A - and in fact, this compiles if you remove the redefinition of onFoo in B - but g++ gives an error that C has no onFoo() function.