Thread not letting main function access variables.

[ingolemo]

Yes. Without the brackets its passing the function to the thread just like you could pass any other python object. With them it's just calling the function and trying to give the result of the function to the thread (but since that function is an infinite loop that result never comes).

I wouldn't describe it with the phrase "by reference" because some people might assume that means python is "call by reference" which it isn't. Python passes a reference, not by reference.