为什么这个代码不能用goroutine打印任何东西 [英] why doesn't this go code print anything with a goroutine

问题描述

我一定错过了一些关于goroutines的基本知识，但是我环顾四周，我看不出有什么理由不这么做......

I must be missing something really basic about goroutines, but I've looked around and I cannot see any reason why this would not work...

package main

import "fmt"

func main() {
    for i := 0; i < 20; i++ {
        //fmt.Println(i)
        go func(j int) {
            fmt.Println(j + 100)
        }(i)
    }
}

推荐答案

goroutines有机会运行。

Your program is finishing before your goroutines have a chance to run.

以下代码使用 WaitGroup ：

package main

import (
    "fmt"
    "sync"
)

func main() {
    var wg sync.WaitGroup
    for i := 0; i < 20; i++ {
        wg.Add(1)
        go func(j int) {
            defer wg.Done()
            fmt.Println(j + 100)
        }(i)
    }
    fmt.Println("Waiting...")
    wg.Wait()
    fmt.Println("Done.")
}

https://play.golang.org/p/lmCPU9-qkB

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