C++ class member pointer to global function

I want to have a class which has as a member a pointer to a function

here is the function pointer:

typedef double (*Function)(double);

here is a function that fits the function pointer definition:

double f1(double x)
{
    return 0;
}

here is the class definion:

class IntegrFunction
{
public:
    Function* function;
};

and somewhere in the main function i want to do something like this:

IntegrFunction func1;
func1.function = f1;

But, this code does not work.

Is it possible to assign to a class member a function pointer to a global function, declared as above? Or do I have to change something in the function pointer definition?

Thanks,