未在其他软件包中定义的html / template类型的Golang全局变量

func main()

package main

import{
  "html/template"
  .....
)

var tmpl = template.New("master")

func main() {

    func init() {

        _, err := tmpl.ParseGlob("templates/*.html")
        if err != nil {
            log.Fatalln("Error loading templates:", err)
        }
....
}    

In another package I write inside a function:

    tmpl.ExecuteTemplate(w, "venue-index.html", res)

but I get an error

tmpl: undefined

I realise that there are other similar questions but the answers have not solved my problem. What am I doing wrong?