Little problem with global variables

[Carlos E. Muñoz]

Hi, maybe it's a noob error but I can't find the solution.

This is the situation, I've a global variable in my main package and I need to change the value with other package.

Maybe this little code can explain the issue a bit better.

-------------------------------------

package main

import "Control"

var JumpFirst bool = false

func main{

         //Proceso con JumpFirst

}

-------------------------------------

package Control

func ChangeFlag (){

        JumpFirst = true

}

[Shawn Milochik]

On Wed, Apr 20, 2016 at 10:49 AM, Carlos E. Muñoz <sna...@gmail.com> wrote:

Hi, maybe it's a noob error but I can't find the solution.

This is the situation, I've a global variable in my main package and I need to change the value with other package.

Maybe this little code can explain the issue a bit better

Why do you think you need to change a global variable in package "main" from an imported package? Imported packages can never be expected to know about things in main.

You can do what you want by (in main) doing: JumpFirst = Control.ChangeFlag()

And have ChangeFlag return a value.

Also, package names are lower-case by convention.

[keith....@gmail.com]

package Control

import "main"

func ChangeFlag (){

        main.JumpFirst = true

[Jakob Borg]

The main package is not importable. If it were, you'd get an import
cycle when using any package that did so. There is no way for a
non-main package to access variables in the main package (other than
by passing them a pointer to one, etc).

//jb

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[Art Mellor]

You can make a sub-package for globals and import that, e.g.

$GOPATH/mypkg/main.go //package main

$GOPATH/mypkg/globals/globals.go // package globals

$GOPATH/otherpkg/other.go // package otherpkg; import "mypkg/globals"

[msilv...@cloudflare.com]

That's not a good approach.

Your main package should consume other packages. The "upstream" package—the one imported by main—should have a way to configure things (via a constructor, exported package variable, config struct, etc).

e.g.

package main

import "github.com/you/yourotherpkg"

func main() {

     opts := &yourotherpkg.Options{Tokens: true, ID: "qwerty"}

     thing, err := yourotherpkg.New(opts)

     if err != nil {

          log.Fatal(err)

     }

     // Use thing

[Carlos E. Muñoz]

Thanks all for your answers, I already solve the problem was a really noob error. 

I had two functions one in main and the other and my custom package, I just move the function in main into my package and also the flags. As it should be from the beginning.