WaitGroup夠程,我從博客https://nathanleclaire.com/blog/2014/02/15/how-to-wait-for-all-goroutines-to-finish-executing-before-continuing/與渠道
學習WaitGroup
代碼:
package main
import (
"fmt"
"sync"
"time"
)
func main() {
messages := make(chan int)
var wg sync.WaitGroup
// you can also add these one at
// a time if you need to
wg.Add(3)
go func() {
defer wg.Done()
time.Sleep(time.Second * 3)
messages <- 1
}()
go func() {
defer wg.Done()
time.Sleep(time.Second * 2)
messages <- 2
}()
go func() {
defer wg.Done()
time.Sleep(time.Second * 1)
messages <- 3
}()
go func() {
for i := range messages {
fmt.Println(i)
}
}()
wg.Wait()
}
我認爲應該以打印3,2和1。但它只打印3,2,但1丟失,問題是什麼?
您可以樹它https://play.golang.org/p/kZCvDhykYM
或者,使它成爲'wg.Add(4)',並在打印例程中放置一個'wg.Done()'作爲好。也就是說,我個人更喜歡把'wg.Wait()'放在goroutine中,並使用通道閉包作爲「完成」信號:https://play.golang.org/p/o-EYS_fK2k – Kaedys