What does this typedef statement mean?

Question

In a C++ reference page they provide some typedef examples and I'm trying to understand what they mean.

// simple typedef typedef unsigned long mylong;   // more complicated typedef typedef int int_t, *intp_t, (&fp)(int, mylong), arr_t[10]; 

So the simple typedef (the first declaration) I understand.

But what are they declaring with the second one (repeated below)?

typedef int int_t, *intp_t, (&fp)(int, ulong), arr_t[10]; 

Particularly what does (&fp)(int, mylong) mean?

Answer 1

It's declaring several typedefs at once, just as you can declare several variables at once. They are all types based on int, but some are modified into compound types.

Let's break it into separate declarations:

typedef int int_t;              // simple int typedef int *intp_t;            // pointer to int typedef int (&fp)(int, ulong);  // reference to function returning int typedef int arr_t[10];          // array of 10 ints