[go] 检查 channel 是否已经被关闭

Posted 2022-11-29 adream307

val, ok := <-ch

如果 channel 已经被关闭，上述调用立刻返回，并且 ok 为 false，完整测试代码如下

package main

import (
	"log"
	"sync"
)

func main() 
	ch := make(chan int)
	var wg sync.WaitGroup
	go func() 
		for i := 0; i <= 100; i++ 
			ch <- i
		
		close(ch)
	()
	wg.Add(1)
	go func() 
		defer wg.Done()
		total := 0
		for 
			if val, ok := <-ch; ok 
				total += val
			 else 
				break
			
		
		log.Printf("recv total = %d", total)
	()
	wg.Wait()

程序输出

2020/09/11 11:52:55 recv total = 5050