// via uname(3) and fall back to the pipe if the kernel version is older than 10.0.

var netpollBreakRd, netpollBreakWr uintptr // for netpollBreak

func addWakeupEvent(kq int32) {
	r, w, errno := nonblockingPipe()
	if errno != 0 {
		println("runtime: pipe failed with", -errno)
		throw("runtime: pipe failed")
	}
	ev := keventt{
		filter: _EVFILT_READ,
		flags:  _EV_ADD,
	}

	wrwake         int32
	pendingUpdates int32

	netpollWakeSig atomic.Uint32 // used to avoid duplicate calls of netpollBreak
)

func netpollinit() {
	// Create the pipe we use to wakeup poll.
	r, w, errno := nonblockingPipe()
	if errno != 0 {
		throw("netpollinit: failed to create pipe")
	}
	rdwake = r
	wrwake = w

	// Pre-allocate array of pollfd structures for poll.
	pfds = make([]pollfd, 1, 128)