What does a function without body mean?

Question

I\'m reading the code that package time, and then I want to know how the func After(d Duration) <-chan Time works.

I found the code f

Answer 1

1) The function is defined here:

// startTimer adds t to the timer heap.
//go:linkname startTimer time.startTimer
func startTimer(t *timer) {
    if raceenabled {
        racerelease(unsafe.Pointer(t))
    }
    addtimer(t)
}

2) Function declarations:

A function declaration may omit the body. Such a declaration provides the signature for a function implemented outside Go, such as an assembly routine.

3) Not every programming language can express its own runtime entirely (C can, for example). Parts of the Go runtime and the standard library are in C, parts are in assembly while some other are in .goc, which is a not well documented hybrid of Go and C.