Example golang of channels and syn.WaitGroup

Test.go

package main

import (
	"fmt"
	"runtime"
	"sync"
)

func init() {
	fmt.Println("func init()")
}

func sq(out chan int) {
	defer close(out)
	x := cap(out)
	for i := 0; i < x; i++ {
		out <- i * i
	}
}

func worker(n int) {
	_ = n * n * n
}

func init() {

	runtime.GOMAXPROCS(runtime.NumCPU())

}

func main() {

	const N = 100000

	ch := make(chan int, N)

	go sq(ch)

	for _ = range ch {
	}

	var wg sync.WaitGroup
	wg.Add(N)

	for i := 0; i < N; i++ {
		go func() {
			defer wg.Done()
			worker(i)
		}()

	}

	wg.Wait()

}