go by example part 3

5-go-by-example/23-goroutines.go

@@ -0,0 +1,32 @@
+// A goroutine is a lightweight thread of execution
+package main
+
+import (
+	"fmt"
+	"time"
+)
+
+func f(from string) {
+	for i := 0; i < 3; i++ {
+		fmt.Println(from, ":", i)
+	}
+}
+
+func main() {
+	// normal function call f(s), running synchronously
+	f("direct")
+
+	// invoke functions in a goroutine, use go f(s)
+	// this new goroutine will execute concurrently with the calling one
+	go f("goroutine")
+
+	// start a goroutine for an anonymous function call
+	go func(msg string) {
+		fmt.Println(msg)
+	}("going")
+
+	// the two function calls are running asynchronously in separate goroutines now
+	// Wait for them to finish (alternate use WaitGroup)
+	time.Sleep(time.Second)
+	fmt.Println("done")
+}