cross plataform compile with Go

main.go

package main

func main() {
	say()
}

say_linux_amd64.go

package main

import "fmt"

func say() {
	fmt.Println("linux")
}

say_windows_amd64.go

package main

import "fmt"

func say() {
	fmt.Println("windows")
}

if you running in a linux amd 64 architeture, the program will print linux, or if you running in a windows amd 64 architeture, the program will print windows

OBS
if you add a function foo() in say_windows_amd64.gofile, and not put your linux version into say_linux_amd64.go, when you call this function on main function, the program will not compile, telling undefined foo()