BOOL ReadFile (
  HANDLE hFile,
  LPVOID lpBuffer,
  DWORD nNumberOfBytesToRead,
  LPDWORD lpNumberOfBytesRead,
  LPOVERLAPPED lpOverlapped);
BOOL WriteFile (
  HANDLE hFile,
  LPCVOID lpBuffer,
  DWORD nNumberOfBytesToWrite,
  LPDWORD lpNumberOfBytesWritten,
  LPOVERLAPPED lpOverlapped);

BOOL ReadFileEx (
  HANDLE hFile,
  LPVOID lpBuffer,
  DWORD nNumberOfBytesToRead,
  LPOVERLAPPED lpOverlapped,
  LPOVERLAPPED_COMPLETION_ROUTINE lpCompletionRoutine);
BOOL WriteFileEx (
  HANDLE hFile,
  LPCVOID lpBuffer,
  DWORD nNumberOfBytesToWrite,
  LPOVERLAPPED lpOverlapped,
  LPOVERLAPPED_COMPLETION_ROUTINE lpCompletionRoutine);

BOOL ReadFileScatter (
  HANDLE hFile,
  FILE_SEGMENT_ELEMENT aSegmentArray [],
  DWORD nNumberOfBytesToRead,
  LPDWORD lpReserved,
  LPOVERLAPPED lpOverlapped);
BOOL WriteFileGather (
  HANDLE hFile,
  FILE_SEGMENT_ELEMENT aSegmentArray [],
  DWORD nNumberOfBytesToWrite,
  LPDWORD lpReserved,
  LPOVERLAPPED lpOverlapped);

BOOL WINAPI GetOverlappedResult (
  HANDLE hFile,
  LPOVERLAPPED lpOverlapped,
  LPDWORD lpNumberOfBytesTransferred,
  BOOL bWait);
BOOL HasOverlappedIoCompleted (
  LPOVERLAPPED lpOverlapped);

BOOL CancelIo (HANDLE hFile);

typedef struct _OVERLAPPED {
  ULONG_PTR Internal;
  ULONG_PTR InternalHigh;
  union {
    struct {
      DWORD Offset;
      DWORD OffsetHigh;
    };
    PVOID Pointer;
  };
  HANDLE hEvent;
}
OVERLAPPED, *LPOVERLAPPED;

typedef union _FILE_SEGMENT_ELEMENT {
  PVOID64 Buffer;
  ULONGLONG Alignment;
}
FILE_SEGMENT_ELEMENT, *PFILE_SEGMENT_ELEMENT;