1 files changed, 20 insertions, 0 deletions
diff --git a/src/sync/example_test.go b/src/sync/example_test.go
index ed240e57ae..a019beebc5 100644
--- a/src/sync/example_test.go
+++ b/src/sync/example_test.go
@@ -26,6 +26,26 @@ func ExampleWaitGroup() {
 		"http://www.example.com/",
 	}
 	for _, url := range urls {
+		// Launch a goroutine to fetch the URL.
+		wg.Go(func() {
+			// Fetch the URL.
+			http.Get(url)
+		})
+	}
+	// Wait for all HTTP fetches to complete.
+	wg.Wait()
+}
+
+// This example is equivalent to the main example, but uses Add/Done
+// instead of Go.
+func ExampleWaitGroup_addAndDone() {
+	var wg sync.WaitGroup
+	var urls = []string{
+		"http://www.golang.org/",
+		"http://www.google.com/",
+		"http://www.example.com/",
+	}
+	for _, url := range urls {
 		// Increment the WaitGroup counter.
 		wg.Add(1)
 		// Launch a goroutine to fetch the URL.