ADD_KEYBOARD_MONITOR@

Dear all,

I wrote a program to output a key code by calling ADD_KEYBOARD_MONITOR@, but it is not working as expected, please help!

      PROGRAM KEYBDKEY
      INCLUDE <windows.ins>
	  INTEGER key
      COMMON key
	  EXTERNAL cb_func
      INTEGER cb_func
      key=0
	  call ADD_KEYBOARD_MONITOR@(cb_func)
1     if(key.eq.0)then
      	goto 1
      else
        goto 2
      endif
2     call print_hex2@(key)
	  PRINT *,key
	  END


      INTEGER FUNCTION cb_func()
      INCLUDE <windows.ins>
      INTEGER key      
      COMMON key
      key = clearwin_info@('KEYBOARD_KEY')
      cb_func = 1
      END