### 实际输出： main done
### 期望输出：有bug ！main done
```
package main
import (
"fmt"
"sync"
)
func main() {
ch2 := make(chan int, 1000)
var wg sync.WaitGroup
go testThreadSate01(ch2, &wg)
go testThreadSate02(ch2, &wg)
go testThreadSate03(ch2, &wg)
go func() {
for {
select {
case res := <-ch2:
if res == 28 {
break
}
case resGt := <-ch2:
if resGt > 28 {
fmt.Println("有bug ！")
break
}
default:
}
}
}()
wg.Wait()
fmt.Println("main done")
}
func testThreadSate03(ch chan int, wg *sync.WaitGroup) {
defer wg.Done()
wg.Add(1)
for j := 21; j <= 30; j++ {
ch <- j
}
}
func testThreadSate01(ch chan int, wg *sync.WaitGroup) {
defer wg.Done()
wg.Add(1)
for j := 0; j <= 10; j++ {
ch <- j
}
}
func testThreadSate02(ch chan int, wg *sync.WaitGroup) {
defer wg.Done()
wg.Add(1)
//time.Sleep(1 * time.Microsecond)
for j := 11; j <= 20; j++ {
ch <- j
}
}
```
`break`跳出的是`select`，不是`for`循环；`select`会随机执行满足条件的语句，感觉`case resGt := <-ch2:`有概率一次都不执行，然后程序卡住。
#4
更多评论
实际上你的协程可能来不及执行wg.Add(1)主程就退出了，而且你的go func() {}是个死循环只不过你的主程没有去等待这个协程才没有卡住
#1
嗯，理解，有什么补救办法吗，我改了另外一种方式，
```
package main
import (
"fmt"
"sync"
)
func main() {
ch2 := make(chan int, 1000)
var wg sync.WaitGroup
wg.Add(4)
go testThreadSate01(ch2, &wg)
go testThreadSate02(ch2, &wg)
go testThreadSate03(ch2, &wg)
go func(wg *sync.WaitGroup) {
for {
select {
case res := <-ch2:
if res == 28 {
break
}
case resGt := <-ch2:
if resGt > 28 {
fmt.Println("有bug ！")
wg.Done()
}
default:
}
}
}(&wg)
wg.Wait()
fmt.Println("main done")
}
func testThreadSate03(ch chan int, wg *sync.WaitGroup) {
defer wg.Done()
for j := 21; j <= 30; j++ {
ch <- j
}
}
func testThreadSate01(ch chan int, wg *sync.WaitGroup) {
defer wg.Done()
for j := 0; j <= 10; j++ {
ch <- j
}
}
func testThreadSate02(ch chan int, wg *sync.WaitGroup) {
defer wg.Done()
//time.Sleep(1 * time.Microsecond)
for j := 11; j <= 20; j++ {
ch <- j
}
}
```
#2
今日阅读排行
一周阅读排行