How can I check if my program is compiled for 32 or 64 bit processor?

Is there any standard method to check os is 32 or 64 bit?
I've check runtime & os package, but can not found.
http://play.golang.org/p/d6NywMDMcY

package main
import "fmt"
import "runtime"
func main() {
	fmt.Println(runtime.GOOS, runtime.GOARCH)
}

What do you mean by a 32- or 64-bit OS? For example, GOARCH=amd64p32, which is used for GOOS=nacl, is amd64 64-bit instructions with 32-bit pointers and 32-bit type ints and uints.

package main
import (
	"fmt"
	"runtime"
	"strconv"
)
func main() {
	const PtrSize = 32 << uintptr(^uintptr(0)>>63)
	fmt.Println(runtime.GOOS, runtime.GOARCH)
	fmt.Println(strconv.IntSize, PtrSize)
}

Playground: http://play.golang.org/p/TKnCA0gqsI

Output:

nacl amd64p32
32 32

and

linux amd64
64 64

You can use the unsafe package and compute the size of a pointer (4 for 32bits, 8 for 64bits).
Here a working example: http://play.golang.org/p/MPap9KMD1y