What are channels used for?

Question

When looking through some Go code I found the following:

  ch := make(chan int) 

I looked up in a online tutorial how Go Channels work:

https://tour.golang.org/concurrency/2

But I find this example unclear.

Can someone give me a easy explanation and an example of the use of channels?

Answer 1

chan is a channel in Golang. In simple word you can think it as a box in which you put a item at one end and then pick it from other end.

Unbuffered Channels

Buffered Channel

This is the small code I have written for you to understand channels. Now change order of go routines and see the outputs. Each time output may differ.

    package main      import (         "fmt"         "time"     )      func main() {         messages := make(chan int)         go func() {             time.Sleep(time.Second * 3)             messages <- 1         }()         go func() {             time.Sleep(time.Second * 2)             messages <- 2         }()          go func() {             time.Sleep(time.Second * 1)             messages <- 3         }()         go func() {             for i := range messages {                 fmt.Println(i)             }         }()         go func() {             time.Sleep(time.Second * 1)             messages <- 4         }()         go func() {             time.Sleep(time.Second * 1)             messages <- 5         }()         time.Sleep(time.Second * 5)     } 

For best understanding visit this blog where go routines and channels are described in GUI.

Visit http://divan.github.io/posts/go_concurrency_visualize/