What does __parameters return?

[simendsjo]

The documentation says "the parameter tuple of a function, 
delegate, or function pointer. This includes the parameter types, 
names, and default values."

.. but what type is it?

Error: argument (int i, char c, string s, bool b = false) to 
typeof is not an expression

How am I supposed to get the parameter names using this?

It's possible to use .stringof, and then regular string handling 
to extract the names, but I guess there should be a simpler way 
if only I knew what it returned.