Is it possible to clear annotation AP?

[MilesChing]

As what I found to clear AP you need to call FPDFAnnotSetAP(annot, 0, nullptr) when nullptr is passed to the third parameter, the AP is cleared for that mode. But in our definition the type of the third parameter is ref ushort where nullptr cannot be passed. Can we fix this or provide someother way to clear AP? When I'm creating an annotation the default AP doesn't do anything but blocking other fields (Rect, Color, etc.) from being rendered.