undefined: w32.GetDC

[scohen28]

w32 compiles fine - trying to do a screen capture:

func screenRect() (image.Rectangle, error) {
hDC := w32.GetDC(0)
if hDC == 0 {
return image.Rectangle{}, fmt.Errorf("Could not Get primary display err:%d\n", w32.GetLastError())
}
defer w32.ReleaseDC(0, hDC)
x := w32.GetDeviceCaps(w32.HDC(hDC), w32.HORZRES)
y := w32.GetDeviceCaps(w32.HDC(hDC), w32.VERTRES)
return image.Rect(0, 0, x, y), nil
}

Compiling with:
GOARCH=386 go build

.\main_windows.go:46: undefined: w32.GetDC
.\main_windows.go:50: undefined: w32.ReleaseDC

So it finds GetDeviceCaps, but not the GetDC - what should I be looking for?