go goroutine 怎样进行错误处理

func main() {
 var wg sync.WaitGroup
 wg.Add(2)
 go func() {
  //... 业务逻辑
  wg.Done()
 }()
 go func() {
  //... 业务逻辑
  wg.Done()
 }()
 wg.Wait()
}

func main() {
 cherrors := make(chan error)
 wgDone := make(chan bool)

 var wg sync.WaitGroup
 wg.Add(2)
 go func() {
  //... 业务逻辑
  wg.Done()
 }()
 go func() {
  //... 业务逻辑
  err := returnErr()
  if err != nil {
   cherrors <- err
  }
  wg.Done()
 }()
 go func() {
  wg.Wait()
  close(wgDone)
 }()

 select {
 case <-wgDone:
  break
 case err := <-cherrors:
  close(cherrors)
  fmt.Println(err)
 }

 time.Sleep(time.Second)
}

func returnErr() error {
 return errors.New("出错啦。。我是错误信息")
}

type Group
    func WithContext(ctx context.Context) (*Group, context.Context)
    func (g *Group) Go(f func() error)
    func (g *Group) Wait() error

func main() {
 group := new(errgroup.Group)

 nums := []int{-1, 0, 1}
 for _, num := range nums {
  num := num
  group.Go(func() error {
   res, err := output(num)
   fmt.Println(res)
   return err
  })
 }

 if err := group.Wait(); err != nil {
  fmt.Println("Get errors: ", err)
 } else {
  fmt.Println("Get all num successfully!")
 }
}

func output(num int) (int, error) {
 if num < 0 {
  return 0, errors.New("math: square root error!")
 }
 return num, nil
}