package main

import (
	"errors"
	"fmt"
	"sync"
	"time"
)

func main() {
	done := make(chan bool)
	errChan := make(chan error)
	wg := new(sync.WaitGroup)
	for i := 0; i < 5; i++ {
		wg.Add(1)
		go Sl(wg, i, errChan)
	}

	go func(w *sync.WaitGroup, d chan bool) {
		w.Wait()
		d <- true
	}(wg, done)

	select {
	case <-done:
	case err := <-errChan:
		fmt.Println(err)

	}
}

func Sl(wg *sync.WaitGroup, i int, errChan chan error) {
	time.Sleep(5 * time.Second)
	fmt.Println("See: ", i)
	if i == 3 { // spits error then the process stops
		errChan <- errors.New("Some error")
	}
	wg.Done()
}