golang/misc/cgo/gmp/fib.go

46 lines
919 B
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.
//go:build ignore
// 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 (
big "."
"runtime"
)
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)
out := make(chan string)
go fibber(c, out, 0)
go fibber(c, out, 1)
for i := 0; i < 200; i++ {
println(<-out)
}
}