33 lines
876 B
Go
33 lines
876 B
Go
// When using channels as function parameters, you can
|
|
// specify if a channel is meant to only send or receive
|
|
// values. This specificity increases the type-safety of
|
|
// the program.
|
|
|
|
package main
|
|
|
|
import "fmt"
|
|
|
|
// This `send` function only accepts a channel for sending
|
|
// values. It would be a compile-time error to try to
|
|
// receive on this channel.
|
|
func send(sendCh chan<- string, msg string) {
|
|
fmt.Println("send message:", msg)
|
|
sendCh <- msg
|
|
}
|
|
|
|
// The `fwd` function accepts one channel for receives
|
|
// (`sendCh`) and a second for sends (`forwardCh`).
|
|
func fwd(sendCh <-chan string, forwardCh chan<- string) {
|
|
msg := <-sendCh
|
|
fmt.Println("forwarding:", msg)
|
|
forwardCh <- msg
|
|
}
|
|
|
|
func main() {
|
|
sendCh := make(chan string, 1)
|
|
forwardCh := make(chan string, 1)
|
|
send(sendCh, "Hello, World!")
|
|
fwd(sendCh, forwardCh)
|
|
fmt.Println("reading messages: ", <-forwardCh)
|
|
}
|