dongzang5815 2019-03-01 23:48
浏览 38
已采纳

为什么我的全局变量没有跨包设置? [重复]

This question already has an answer here:

I have the following code:

main.go:

package main

import (
    "fmt"

    "./globalvar"

    "github.com/Denton-L/gotest/usevar"
)

func main() {
    globalvar.GlobalNum = 42
    fmt.Println(globalvar.GlobalNum)
    usevar.PrintGlobal()
}

usevar/usevar.go:

package usevar

import (
    "fmt"

    "github.com/Denton-L/gotest/globalvar"
)

func PrintGlobal() {
    fmt.Println(globalvar.GlobalNum)
}

globalvar/globalvar.go:

package globalvar

var GlobalNum int

and I'm compiling with go build main.go. When I run ./main, I get

42
0

as output but I am expecting

42
42

Why is this happening?

EDIT: Note that I'm able to access the global variables but they contain unexpected values so this is not a duplicate of Golang Global Variable access.

</div>
  • 写回答

1条回答 默认 最新

  • dongnvwang8591 2019-03-01 23:53
    关注

    The reason why this is happening is because we're mixing relative and remote imports. In main.go, the globalvar package is imported as ./globalvar but usevar/usevar.go imports it as github.com/Denton-L/gotest/globalvar. Therefore, Go considers these to be separate packages with their own namespaces and thus, they have their own separate global variables that happen to be named identically.

    In order to solve this, change the relative import to be a remote import, so the main.go import statement should look like this:

    import (
        "fmt"
    
        "github.com/Denton-L/gotest/globalvar"
        "github.com/Denton-L/gotest/usevar"
    )
    

    This will let the compiler know that they are actually the same package and, thus, the global variable will be shared.

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论

报告相同问题?

悬赏问题

  • ¥15 三电平逆变器中点电位平衡问题
  • ¥20 这怎么写啊 java课设
  • ¥15 用C语言完成一个复杂的游戏
  • ¥15 如何批量更改很多个文件夹里的文件名中包含文件夹名?
  • ¥50 MTK手机模拟HID鼠标出现卡顿
  • ¥20 求下下面这个数据结构代码
  • ¥20 前端 二进制文件流图片转化异常
  • ¥15 github上的这个C语言项目如何跑起来
  • ¥15 java 判断某个数 区间是否存在
  • ¥15 appium控制多个雷电模拟器问题