pub type IOMMU_REGISTER_INTERFACE_STATE_CHANGE_CALLBACK = Option<unsafe extern "system" fn(statechangecallback: PIOMMU_INTERFACE_STATE_CHANGE_CALLBACK, context: *const c_void, dmadevice: *const IOMMU_DMA_DEVICE, statefields: *const IOMMU_INTERFACE_STATE_CHANGE_FIELDS) -> NTSTATUS>;
enum IOMMU_REGISTER_INTERFACE_STATE_CHANGE_CALLBACK {
None,
Some(unsafe extern "system" fn(_: Option<unsafe extern "system" fn()>, _: *const c_void, _: *const IOMMU_DMA_DEVICE, _: *const IOMMU_INTERFACE_STATE_CHANGE_FIELDS) -> NTSTATUS),
}