// +build go1.9 package main import ( "fmt" "sync" "time" ) func main() { var m sync.Map for i := 0; i < 3; i++ { go func(i int) { for j := 0; ; j++ { m.Store(i, j) } }(i) } for i := 0; i < 10; i++ { m.Range(func(key, value interface{}) bool { fmt.Printf("%d: %d\t", key, value) return true }) fmt.Println() time.Sleep(time.Second) } }