Get terminal size in Go

How to get tty size with Golang? I am trying do this with executing stty size command, but I can't craft code right.

package main

import (
  "os/exec"
  "fmt"
  "log"
)

func main() {
  out, err := exec.Command("stty", "size").Output()
  fmt.Printf("out: %#v\n", out)
  fmt.Printf("err: %#v\n", err)
  if err != nil {
    log.Fatal(err)
  }
}

Output:

out: []byte{}
err: &exec.ExitError{ProcessState:(*os.ProcessState)(0xc200066520)}
2013/05/16 02:35:57 exit status 1
exit status 1

I think this is because Go spawns a process not related to the current tty, with which it is working. How can I relate the command to current terminal in order to get its size?

It works if you give the child process access to the parent's stdin:

package main

import (
  "os/exec"
  "fmt"
  "log"
  "os"
)

func main() {
  cmd := exec.Command("stty", "size")
  cmd.Stdin = os.Stdin
  out, err := cmd.Output()
  fmt.Printf("out: %#v\n", string(out))
  fmt.Printf("err: %#v\n", err)
  if err != nil {
    log.Fatal(err)
  }
}

Yields:

out: "36 118\n"
err: <nil>