Question

我无法在select语句之外传递字符串变量。

案例（简化）：

我有一个同步脚本，它使用select和两个选项

timeout（3秒）
default使用频道更改字符串的值。

当我们检查select内的字符串结果时 - 它显示正确。

但是一旦我们离开select语句，变量就会恢复为之前的值。

package main

import (
    "log"
    "time"
)

func main() {
    timeout := time.After(3 * time.Second)
    pollInt := time.Second

    var ret string = "EMPTY"

OuterLoop:
    for {
        select {
        case <-timeout:
            log.Printf("[select][timeout] select timeout, break select and for loops")
            break OuterLoop

        default:
            log.Printf("[select][default] Processing our actions")

            ch := make(chan string, 1)

            go func(ch chan string) {
                var res string = "NOT EMPTY"
                ch <- res
            }(ch)

            select {
            case ret := <-ch:
                log.Printf("channel has a result")
                log.Printf("showing content of string AT THE SELECT: %v", ret)
            case <-time.After(1 * time.Second):
                log.Printf("timeout")

            }

        }
        log.Printf("[for] Sleep for a second..")
        time.Sleep(pollInt)
    }

    log.Printf("Starting to do some important actions.. (regardless was previous actions success or timeout)")
    /* ... */

    log.Printf("showing content of string: %v", ret)

    if ret == "NOT EMPTY" {
        log.Printf("SCRIPT FINISHED CORRECTLY")
    } else {
        log.Printf("SCRIPT FAILED")
    }

}

脚本运行结果：

2009/11/10 23:00:00 [select][default] Processing our actions
2009/11/10 23:00:00 channel has a result
2009/11/10 23:00:00 showing content of string AT THE SELECT: NOT EMPTY
2009/11/10 23:00:00 [for] Sleep for a second..
2009/11/10 23:00:01 [select][default] Processing our actions
2009/11/10 23:00:01 channel has a result
2009/11/10 23:00:01 showing content of string AT THE SELECT: NOT EMPTY
2009/11/10 23:00:01 [for] Sleep for a second..
2009/11/10 23:00:02 [select][default] Processing our actions
2009/11/10 23:00:02 channel has a result
2009/11/10 23:00:02 showing content of string AT THE SELECT: NOT EMPTY
2009/11/10 23:00:02 [for] Sleep for a second..
2009/11/10 23:00:03 [select][timeout] select timeout, break select and for loops
2009/11/10 23:00:03 Starting to do some important actions.. (regardless was previous actions success or timeout)
2009/11/10 23:00:03 showing content of string: EMPTY
2009/11/10 23:00:03 SCRIPT FAILED

但我希望：

2009/11/10 23:00:00 [select][default] Processing our actions
2009/11/10 23:00:00 channel has a result
2009/11/10 23:00:00 showing content of string AT THE SELECT: NOT EMPTY
2009/11/10 23:00:00 [for] Sleep for a second..
2009/11/10 23:00:01 [select][default] Processing our actions
2009/11/10 23:00:01 channel has a result
2009/11/10 23:00:01 showing content of string AT THE SELECT: NOT EMPTY
2009/11/10 23:00:01 [for] Sleep for a second..
2009/11/10 23:00:02 [select][default] Processing our actions
2009/11/10 23:00:02 channel has a result
2009/11/10 23:00:02 showing content of string AT THE SELECT: NOT EMPTY
2009/11/10 23:00:02 [for] Sleep for a second..
2009/11/10 23:00:03 [select][timeout] select timeout, break select and for loops
2009/11/10 23:00:03 Starting to do some important actions.. (regardless was previous actions success or timeout)
2009/11/10 23:00:03 showing content of string: NOT EMPTY
2009/11/10 23:00:03 SCRIPT FINISHED CORRECTLY

游乐场：https://play.golang.org/p/uPKZtQQkm7p

有什么想法吗？

如何在全局范围内将select的输出传递给select之外？

0 个答案: