Calc height of title bar or client area top left?

Indiepath: Sure I'll switch all thisstuff off on the Max/Linux version and have to find out equivalent stuff for those platforms (which WON'T be easy) or leave the tweaks out altogeher.

Anyway I'm having trouble with this:

Strict

Type TWindowInfo
    Field cbSize
    Field rcWindow:TRect
    Field rcClient:TRect
    Field dwStyle
    Field dwExStyle
    Field dwWindowStatus 
    Field cxWindowBorders
    Field cyWindowBorders
    Field atomWindowType:Short 'Research shows an Atom to be a 16-bit value (I hope)
    Field wCreatorVersion:Short
End Type

Type TRect
	Field L%, T%, R%, B%
End Type

Extern "win32"
	Function GetWindowInfo(hWnd%, WindowInfo: Byte Ptr)       
End Extern

Function ccGetWindowInfo:TWindowInfo(hWnd%)
	Local wi:TWindowInfo = New TWindowInfo
	wi.cbSize = SizeOf(wi)
	wi.rcWindow = New TRect
	wi.rcClient = New TRect
	GetWindowInfo(hwnd,wi)	
	Return wi
End Function       

Graphics 800,600,0

Local wi:TWindowInfo = ccGetWindowInfo(GetActiveWindow()) 
Cls
DrawText wi.rcwindow.l,0,0
Flip
WaitKey

I getting a MAV on the drawtext line. Clearly GetWindowInfo is just overwriting it with junk or something. Any ideas?