三个线程顺序打印ABC

condition.go

package main

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

var l = sync.Mutex{}
var cond = sync.NewCond(&l)

var turn = 0

func main() {
	s := []string{"A", "B", "C"}
	for _, item := range s {
		go func(x string) {
			for i := 0; i < 10; i++ {
				//fmt.Println("try get lock ", x)
				l.Lock()
				for s[turn] != x {
					cond.Wait()
				}
				// my turn
				fmt.Println(i, x)
				turn = (turn + 1) % 3
				cond.Broadcast()
				cond.Wait()
				l.Unlock()
			}
		}(item)
	}
	time.Sleep(time.Hour)
}