)

func fibber(c chan *big.Int, out chan string, n int64) {
	// Keep the fibbers in dedicated operating system
	// threads, so that this program tests coordination
	// between pthreads and not just goroutines.
	runtime.LockOSThread()

	i := big.NewInt(n)
	if n == 0 {
		c <- i
	}
	for {
		j := <-c
		out <- j.String()
		i.Add(i, j)
		c <- i
	}
}

func main() {
	c := make(chan *big.Int)

	// leave the thread locked to die without a risk of the current thread
	// left lingering with incorrect namespace.
	var innerError error
	go func() {
		defer wg.Done()
		runtime.LockOSThread()
		innerError = containedCall()
	}()
	wg.Wait()

	return innerError