Comma omitted in variadic function declaration in C++

Question

I am used to declaring variadic functions like this:

int f(int n, ...);

When reading The C++ Programming Language I found that the dec

Answer 1

According to § 8.3.5.4 of the C++ standard (current draft):

Where syntactically correct and where “...” is not part of an abstract-declarator, “, ...” is synonymous with “...”.

In short, in C++ ... (ellipsis) is an operator in its own right and so can be used without the comma, but use of the comma is retained for backwards compatibility.