misc/cgo/stdio/fib.go

// Copyright 2009 The Go Authors.  All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Compute Fibonacci numbers with two goroutines
// that pass integers back and forth.  No actual
// concurrency, just threads and synchronization
// and foreign code on multiple pthreads.

package main

import (
	"runtime";
	"stdio";
	"strconv";
)

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

	if i == 0 {
		c <- i
	}
	for {
		j := <-c;
		stdio.Puts(strconv.Itoa64(j));
		out <- j;
		<-out;
		i += j;
		c <- i;
	}
}

func main() {
	c := make(chan int64);
	out := make(chan int64);
	go fibber(c, out, 0);
	go fibber(c, out, 1);
	<-out;
	for i := 0; i < 90; i++ {
		out <- 1;
		<-out;
	}
}