Golang : How to capture return values from goroutines?

Got a question asked by a newbie on Facebook yesterday. Her question was how to capture the return values generated by goroutines.

Alright, the simplest way to capture the output generated by goroutines is to use channels. The sample Golang code below demonstrate how to use channels to capture the return values.

 package main

 import "fmt"

 func say(msg chan<- string) {
  msg <- "Hello, 世界!"
 }

 // return multiple values, in this case it is 2
 func trueOrFalse(answer chan<- bool) {
  answer <- true
  answer <- false
 }

 func main() {
  messageChannel := make(chan string)

  // execute Gorountine and return the value into messageChannel
  go say(messageChannel)

  fmt.Println(<-messageChannel)

  // the channel has type. To receive 2 boolean values, we use increase it by 2

  booleanChannel := make(chan bool, 2)

  go trueOrFalse(booleanChannel)

  fmt.Println(<-booleanChannel) // true
  fmt.Println(<-booleanChannel) // false -- and also pop the stack

 }

Output:

 Hello, 世界!
 true
 false

References :

https://socketloop.com/tutorials/golang-channels-and-buffered-channels-examples

https://socketloop.com/tutorials/golang-concurrency-and-goroutine