goroutine并发之callback回调

package main

import (
	"fmt"
	"strings"
	"sync"
)

var wait sync.WaitGroup

func main() {

	wait.Add(1)

	toUpperAsync("Hello Callback!", func(v string) {
		fmt.Printf("Callback: %s\n", v)
		wait.Done()
	})
	println("Waiting async response...")
	wait.Wait()
}

func toUpperAsync(word string, f func(string)) {
	go func() {
		f(strings.ToUpper(word))
	}()
}