Golang : How to capture return values from goroutines?


Tags : golang channels goroutines sync-waitgroup

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

  See also : Golang : Channels and buffered channels examples



Tags : golang channels goroutines sync-waitgroup

By Adam Ng(黃武俊)

IF you gain some knowledge or the information here solved your programming problem. Please consider donating to the less fortunate or some charities that you like. Apart from donation, planting trees, volunteering or reducing your carbon footprint will be great too.


Advertisement