Cannot run multiple go files

Question

I have two go files in a directory.

  Go  
   ├── mains.go  
   └── vars.go

The code for the mains.go and vars.go are given below:

mains.go
--------
package main

import "fmt"

func main() {
     fmt.Println("This is the mains file")
}


vars.go
--------
package main

import "fmt"

func main() {
     fmt.Println("This is the vars file")
}

While running the file individually using the terminal command

go run mains.go
go run vars.go

I am getting the output. When I am using VScode, I am getting the following error

main redeclared in this block
previous declaration at ./mains.go:5:6

Due to this error, I am not able to run the code. The code runs fine when each file is separated into folders. I tried to remove the main declaration from the file before saving but the autocomplete/autoformat feature fills the package main & import "fmt" commands automatically. My doubts are :

• Is this the problem with the editor? (As the terminal commands run fine)

• Any other recommended IDE for go?

My specs

Ubuntu : 16.04
Visual Studio Code : 1.23.1
go version : 1.9.2

Answer 1

It doesn't make sense to redeclare the main function twice in the same package. You mentioned that the code works fine placing the mains.go and vars.go files in separate folders. That is expected and this is what needs to be done - placing the files in different folders.

If however, you need to run both functions, change your setup using a simple goroutine as defined below:

// main.go
package main

import (
          "fmt"
          "sync"
)

var wg sync.WaitGroup

func main() {
     fmt.Println("This is the mains file")

     wg.Add(1)
     go vars()

     // do other stuff...
     wg.Wait()
}

// vars.go
package main

import "fmt"

func vars() {
     fmt.Println("This is the vars file")
     // do other stuff...

     wg.Done()
}

This would allow you to run both functions at the same time whilst still in the same package. Since the functions can't have the same function name: main(), you need to change one of them to something else as I've done.

Note however that you could simply call the vars() function without doing so concurrently.