// Go's _select_ lets you wait on multiple channel // operations. Combining goroutines and channels with // select is a powerful feature of Go. package main import ( "fmt" "time" ) func main() { // For our example we'll select across two channels. c1 := make(chan string) c2 := make(chan string) // Each channel will receive a value after some amount // of time, to simulate e.g. blocking RPC operations // executing in concurrent goroutines. go func() { time.Sleep(1 * time.Second) c1 <- "one" }() go func() { time.Sleep(2 * time.Second) c2 <- "two" }() // We'll use `select` to await both of these values // simultaneously, printing each one as it arrives. for i := 0; i < 2; i++ { select { case msg1 := <-c1: fmt.Println("received", msg1) case msg2 := <-c2: fmt.Println("received", msg2) } } }