1// Copyright 2009 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5//go:build ignore
6
7// Compute Fibonacci numbers with two goroutines
8// that pass integers back and forth.  No actual
9// concurrency, just threads and synchronization
10// and foreign code on multiple pthreads.
11
12package main
13
14import (
15	big "."
16	"runtime"
17)
18
19func fibber(c chan *big.Int, out chan string, n int64) {
20	// Keep the fibbers in dedicated operating system
21	// threads, so that this program tests coordination
22	// between pthreads and not just goroutines.
23	runtime.LockOSThread()
24
25	i := big.NewInt(n)
26	if n == 0 {
27		c <- i
28	}
29	for {
30		j := <-c
31		out <- j.String()
32		i.Add(i, j)
33		c <- i
34	}
35}
36
37func main() {
38	c := make(chan *big.Int)
39	out := make(chan string)
40	go fibber(c, out, 0)
41	go fibber(c, out, 1)
42	for i := 0; i < 200; i++ {
43		println(<-out)
44	}
45}
46