Golang::WaitGroup 等待所有goroutine退出-蒲公英云

Golang::WaitGroup 等待所有goroutine退出

简介

waitgroup类似于的信号量，用于等待所有的goroutine退出，基本的操作包括
add(int) 增加信号的值,add的参数应该都为正数，done() 减少信号的值,相当于add(-1) ，wait() 等待信号量值为0，等待期间会一直阻塞

code

package main
import (
    "fmt"
    "sync"
    "time"
)
var waitGroutp = sync.WaitGroup{}
func goroutine1() {
    time.Sleep(time.Second * 3)
    waitGroutp.Done()
    fmt.Println("goroutine1退出")
}
func goroutine2() {
    time.Sleep(time.Second * 8)
    waitGroutp.Done()
    fmt.Println("goroutine2退出")
}
func goroutine3() {
    time.Sleep(time.Second * 1)
    waitGroutp.Done()
    fmt.Println("goroutine3退出")
}
func goroutine4() {
    time.Sleep(time.Second * 2)
    waitGroutp.Done()
    fmt.Println("goroutine4退出")
}
func main() {
    fmt.Println("waitgroup测试")
    go goroutine1()
    go goroutine2()
    go goroutine3()
    go goroutine4()
    waitGroutp.Add(4)
    //waitGroutp.Add(5) //add 大于开goroutie数目会死锁，
    //waitGroutp.Add(2) //少了会panic sync: negative WaitGroup counter
    waitGroutp.Wait()
    time.Sleep(time.Second * 2)
    fmt.Println("所有goroutine已经退出")
}