Always have x number of goroutines running at any time

Question

I see lots of tutorials and examples on how to make Go wait for x number of goroutines to finish, but what I\'m trying to do is have ensure there are always x number running

Answer 1

Thanks to everyone for helping me out with this. However, I don't feel that anyone really provided something that both worked and was simple/understandable, although you did all help me understand the technique.

What I have done in the end is I think much more understandable and practical as an answer to my specific question, so I will post it here in case anyone else has the same question.

Somehow this ended up looking a lot like what OneOfOne posted, which is great because now I understand that. But OneOfOne's code I found very difficult to understand at first because of the passing functions to functions made it quite confusing to understand what bit was for what. I think this way makes a lot more sense:

package main

import (
"fmt"
"sync"
)

const xthreads = 5 // Total number of threads to use, excluding the main() thread

func doSomething(a int) {
    fmt.Println("My job is",a)
    return
}

func main() {
    var ch = make(chan int, 50) // This number 50 can be anything as long as it's larger than xthreads
    var wg sync.WaitGroup

    // This starts xthreads number of goroutines that wait for something to do
    wg.Add(xthreads)
    for i:=0; i