functionID is what's called "standard level" in the link I posted. So it should be 4 (you can also see that in the C version btw.).
I agree that the example isn't very well tested - the author probably pulled it out of some existing code and wasn't very careful.
It's not that I thought that this information was difficult to look up, rather it seemed very odd information to be missing from a link that was submitted as useful/interesting.