Question

I was going through the stdio.h header file that comes with MinGW and noticed that the printf function is declared like this:

int printf (const char *__format, ...)
{
    //body omitted
}

I have never seen ellipsis in function parameter list before so I tried it out. It compiles and runs without error. What, then, is the purpose of “…”?

Answer 1

That means that the function is a variadic function that takes a variable number of parameters:

http://en.wikipedia.org/wiki/Variadic_function

printf() itself is probably the best example of a variadic function.