As we know that a channel is a medium of communication between concurrently running goroutines so that they can send and receive data to each other. By default a channel is bidirectional but you can create a unidirectional channel also. A channel that can only receive data or a channel that can only send data is the unidirectional channel. The unidirectional channel can also create with the help of make() function as shown below:
// Only to receive data c1:= make(<- chan bool) // Only to send data c2:= make(chan<- bool)
Example 1:Â
Go
// Go program to illustrate the concept // of the unidirectional channel package main Â
import "fmt" Â
// Main function func main() { Â
    // Only for receiving     mychanl1 := make(<- chan string ) Â
    // Only for sending     mychanl2 := make( chan <- string ) Â
    // Display the types of channels     fmt.Printf("%T", mychanl1)     fmt.Printf("\n%T", mychanl2) } |
Output:
<-chan string chan<- string
Converting Bidirectional Channel into the Unidirectional Channel
In Go language, you are allowed to convert a bidirectional channel into a unidirectional channel, or in other words, you can convert a bidirectional channel into a receive-only or send-only channel, but vice versa is not possible. As shown in the below program:Â
Example:Â
Go
// Go program to illustrate how to convert // bidirectional channel into the // unidirectional channel package main Â
import "fmt" Â
func sending(s chan <- string ) { Â Â Â Â s <- "GeeksforGeeks" } Â
func main() { Â
    // Creating a bidirectional channel     mychanl := make( chan string ) Â
    // Here, sending() function convert     // the bidirectional channel     // into send only channel     go sending(mychanl) Â
    // Here, the channel is sent     // only inside the goroutine     // outside the goroutine the     // channel is bidirectional     // So, it print GeeksforGeeks     fmt.Println(<-mychanl) } |
Output:
GeeksforGeeks
Use of Unidirectional Channel: The unidirectional channel is used to provide the type-safety of the program so, that the program gives less error. Or you can also use a unidirectional channel when you want to create a channel that can only send or receive data.