go例程通道中的同步问题

package main

import (
    "fmt"
    "sync"
)

func worker(id int, jobs <-chan int, results chan<- int) {
    for j := range jobs {
        fmt.Printf("Worker %d started job %d\n", id, j)
        results <- j * 2
        fmt.Printf("Worker %d finished job %d\n", id, j)
    }
}

func main() {
    jobs := make(chan int, 100)
    results := make(chan int, 100)

    var wg sync.WaitGroup
    for w := 1; w <= 3; w++ {
        wg.Add(1)
        go func(id int) {
            defer wg.Done()
            worker(id, jobs, results)
        }(w)
    }

    for j := 1; j <= 5; j++ {
        jobs <- j
    }
    close(jobs)

    go func() {
        wg.Wait()
        close(results)
    }()

    for r := range results {
        fmt.Println("Result:", r)
    }
}

package main

import (
    "fmt"
    "time"
)

func deadlockExample() {
    ch := make(chan int)
    ch <- 1 // 这里会阻塞，因为没有接收者
    fmt.Println(<-ch)
}

func noDeadlockExample() {
    ch := make(chan int)
    go func() {
        ch <- 1 // 这里不会阻塞，因为有另一个例程在接收
    }()
    fmt.Println(<-ch)
}

func main() {
    // deadlockExample() // 这会导致死锁
    noDeadlockExample()
    time.Sleep(time.Second)
}