频道/ Goroutines投掷错误

Question

我目前正在学习本教程http://www.miek.nl/files/go/20120807-go.pdf,第7章讨论了频道/ goroutines

但是,示例代码在运行之后就为我抛出了一个错误.

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)
    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 +0xee

goroutine 2 [syscall]:
created by runtime.main
    /build/buildd/golang-1/src/pkg/runtime/proc.c:221

goroutine 3 [chan send (nil chan)]:
main.ready(0x80bb0d4, 0x3, 0x2, 0x0)
    /home/daniel/Dropbox/code/go/goroutines.go:13 +0xe5
created by main.main
    /home/daniel/Dropbox/code/go/goroutines.go:18 +0x5e

goroutine 4 [chan send (nil chan)]:
main.ready(0x80bba30, 0x6, 0x1, 0x0)
    /home/daniel/Dropbox/code/go/goroutines.go:13 +0xe5
created by main.main
    /home/daniel/Dropbox/code/go/goroutines.go:19 +0x80

goroutine 5 [timer goroutine (idle)]:
created by addtimer
    /build/buildd/golang-1/src/pkg/runtime/ztime_386.c:69
exit status 2

我的代码有问题吗？

任何帮助,将不胜感激

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自从它宣布一个新的以来没有使用全球.

请注意,您不必在内部main()创建通道,在声明通道时进行通道:

var c = make(chan int)