Go language MessageBox usage example

package main
import (
       "syscall"
       "unsafe"
       "fmt"
)
func abort(funcname string, err int) {
       panic(funcname + " failed: " + (err).Error())
}
var (
       kernel32, _ = ("")
       getModuleHandle, _ = (kernel32, "GetModuleHandleW")
       user32, _ = ("")
       messageBox, _ = (user32, "MessageBoxW")
)
const (
       MB_OK                      = 0x00000000
       MB_OKCANCEL                = 0x00000001
       MB_ABORTRETRYIGNORE        = 0x00000002
       MB_YESNOCANCEL             = 0x00000003
       MB_YESNO                   = 0x00000004
       MB_RETRYCANCEL             = 0x00000005
       MB_CANCELTRYCONTINUE       = 0x00000006
       MB_ICONHAND                = 0x00000010
       MB_ICONQUESTION            = 0x00000020
       MB_ICONEXCLAMATION         = 0x00000030
       MB_ICONASTERISK            = 0x00000040
       MB_USERICON                = 0x00000080
       MB_ICONWARNING             = MB_ICONEXCLAMATION
       MB_ICONERROR               = MB_ICONHAND
       MB_ICONINFORMATION         = MB_ICONASTERISK
       MB_ICONSTOP                = MB_ICONHAND
       MB_DEFBUTTON1              = 0x00000000
       MB_DEFBUTTON2              = 0x00000100
       MB_DEFBUTTON3              = 0x00000200
       MB_DEFBUTTON4              = 0x00000300
)
func MessageBox(caption, text string, style uintptr) (result int) {
       // var hwnd HWND
       ret, _, callErr := syscall.Syscall6(uintptr(messageBox), 4,
               0, // HWND
               uintptr((syscall.StringToUTF16Ptr(text))), // Text
               uintptr((syscall.StringToUTF16Ptr(caption))), // Caption
               style, // type
               0,
               0)
       if callErr != 0 {
               abort("Call MessageBox", int(callErr))
       }
       result = int(ret)
       return
}
func main() {
       defer (kernel32)
       defer (user32)
       ("Retern: %d\n", MessageBox("Done Title", "This test is Done.", MB_YESNOCANCEL))
}
func init() {
       ("Starting Up\n")
}