通道/ Goroutines抛出错误

Question

我目前正在关注本教程http://www.miek.nl/files/go/20120807-go.pdf，并在第7章中讨论了渠道/ goroutines但是，示例代码在运行后立即对我抛出错误。package mainimport (    "fmt"    "time")var c chan intfunc ready(w string, sec int) {    time.Sleep(time.Duration(sec) * time.Second)    fmt.Println(w, "is ready!")    c <- 1}func main() {    c := make(chan int)    go ready("Tea", 2)    go ready("Coffee", 1)    fmt.Println("Waiting...")    <-c    <-c}这是执行代码时的输出daniel:go> go run goroutines.go Waiting...Coffee is ready!Tea is ready!throw: all goroutines are asleep - deadlock!goroutine 1 [chan receive]:main.main()    /home/daniel/Dropbox/code/go/goroutines.go:21 +0xeegoroutine 2 [syscall]:created by runtime.main    /build/buildd/golang-1/src/pkg/runtime/proc.c:221goroutine 3 [chan send (nil chan)]:main.ready(0x80bb0d4, 0x3, 0x2, 0x0)    /home/daniel/Dropbox/code/go/goroutines.go:13 +0xe5created by main.main    /home/daniel/Dropbox/code/go/goroutines.go:18 +0x5egoroutine 4 [chan send (nil chan)]:main.ready(0x80bba30, 0x6, 0x1, 0x0)    /home/daniel/Dropbox/code/go/goroutines.go:13 +0xe5created by main.main    /home/daniel/Dropbox/code/go/goroutines.go:19 +0x80goroutine 5 [timer goroutine (idle)]:created by addtimer    /build/buildd/golang-1/src/pkg/runtime/ztime_386.c:69exit status 2我的代码有问题吗？

Answer 1

是的，只是一个错字：

package main

import (

    "fmt"

    "time"

)

var c chan int

func ready(w string, sec int) {

    time.Sleep(time.Duration(sec) * time.Second)

    fmt.Println(w, "is ready!")

    c <- 1

}

func main() {

    c = make(chan int) // previously c := make(chan int)

    go ready("Tea", 2)

    go ready("Coffee", 1)

    fmt.Println("Waiting...")

    <-c

    <-c

}

main()c因为它声明了一个新的全局变量，所以没有使用它。

请注意，您不必main()在声明以下内容的内部创建频道：

var c = make(chan int)