golang顺序输出

seq-output.go

import (
	"fmt"
	"sync/atomic"
)

const (
	total   = 30
	threads = 3
)

var (
	counter int32
	done    = make(chan struct{})
)

func main() {
	var chns [threads]chan struct{}

	for i := 0; i < threads; i++ {
		chns[i] = make(chan struct{})
	}
	var next chan struct{}
	for i := 0; i < threads; i++ {
		if i == threads-1 {
			next = chns[0]
		} else {
			next = chns[i+1]
		}
		go func(mine, next chan struct{}, toPrint string) {
			for {
				<-mine
				fmt.Println(toPrint)
				if atomic.AddInt32(&counter, 1) == total {
					close(done)
					return
				}
				next <- struct{}{}
			}
		}(chns[i], next, string([]byte{'A' + byte(i)}))
	}
	chns[0] <- struct{}{}
	<-done
}