In a C function declaration, what does "..." as the last parameter do?

Question

Often I see a function declared like this:

void Feeder(char *buff, ...)

what does "..." mean?

Answer 1

It allows a variable number of arguments of unspecified type (like printf does).

You have to access the arguments with the va_start, va_arg and va_end functions.

See http://publications.gbdirect.co.uk/c_book/chapter9/stdarg.html or Where in the C standard variadic functions are described? for more information