go - Meaning of ...interface{} (dot dot dot interface)

Question

Below is a piece of Go code I have question about. Specifically, what is a in this function?

func DPrintf(format string, a ...interface{}) (n int, err error) {
  if Debug > 0 {
    n, err = fmt.Printf(format, a...)
  }
  return
}

Could anyone tell me what the three dots are here? And what does ...interface{} do?

Answer 1

Waitting for answers