_In_ PDEVICE_OBJECT DeviceObject
NTSTATUS(* NTAPI)(IN PFILE_FULL_EA_INFORMATION EaBuffer, IN ULONG EaLength, OUT PULONG ErrorOffset)
NTSTATUS NTAPI IoCallDriver(IN PDEVICE_OBJECT DeviceObject, IN PIRP Irp)
#define IoSkipCurrentIrpStackLocation(Irp)
struct _BEEP_DEVICE_EXTENSION * PDEVICE_EXTENSION