Goroutine存储通道值没有死锁

Question

This code runs and ends with no deadlock error. Why?

func main() {
    ch := make(chan int)
    go func() {
        ch<-1
        ch<-2
    }()

    time.Sleep(time.Second)
}

Answer 1

The unbuffered channel needs two end points to work, so let's start with correct example:

package main

func main() {
    go fun2()
    <-ch
    <-ch
}
func fun2() {
    ch <- 1
    ch <- 2
}

var ch = make(chan int)

Here fun2() sends two values and main() receives two values.

---

Your sample code has only one end point so the channel is not correctly constructed, so it is deadlock, but the main goroutines exits normally so you don't see the error. Here, there is no second end point, so this is deadlock:

package main

func main() {
    var ch = make(chan int)
    ch <- 1
}

Output:

fatal error: all goroutines are asleep - deadlock!