How does this #define example work?

Question

#define IF_DESKTOP(...)
static IF_DESKTOP(long long) int unpack()

I know that if #define MAX 3 is given then wherever MAX is used in the program it will be replaced by three. But here i did not understand what (...) does?

Answer 1

Here it will not do any work. As you said MAX is replaced with 3. So like that it will work Here IF_DESKTOP(...) is assigned as empty place. So the second one is changed into

static int unpack()

I confirmed that using cc -E. Sorry for previous answer.