Imported Upstream version 60upstream/60

1 files changed, 43 insertions, 0 deletions

diff --git a/misc/cgo/gmp/fib.go b/misc/cgo/gmp/fib.go
new file mode 100644
index 000000000..3eda39e17
--- /dev/null
+++ b/misc/cgo/gmp/fib.go
@@ -0,0 +1,43 @@
+// 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 (
+	big "gmp"
+	"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)
+	}
+}