golang sync.WaitGroup

//阻塞，直到WaitGroup中的因此過程完成。
import (
    "fmt"
    "sync"
)

func wgProcess(wg *sync.WaitGroup, id int) {
    fmt.Printf("process:%d is going!\n", id)
    //if id == 2 {
    //    return
    //}
    wg.Done()
}

func main() {
    //var wg sync.WaitGroup
    wg := new(sync.WaitGroup)
    for i := 0; i < 3; i++ {
        wg.Add(1)
        go wgProcess(wg, i)
    }
    wg.Wait()
    fmt.Println("after wait group")
}