Superstar's New World

BOOL DeviceIoControl ( HANDLE FileHandle,
                                      DWORD dwIoControlCode,
                                      LPVOID lpInBuffer,
                                      DWORD nInBufferSize,
                                      LPVOID lpOutBuffer,
                                      DWORD nOutBufferSize,
                                      LPDWORD lpBytesReturned,
                                      LPOVERLAPPED lpOverLapped
                                    );

FileHandle - Handle to device of interest
dwIoControlCode - Control code of operation to perform
lpInBuffer - Pointer to buffer to supply input data(App -> Device Driver)
nInBufferSize - Size of input buffer
lpOutBuffer - Pointer to buffer to receive output data(Device Driver -> App)
nOutBufferSize - Size of output buffer
lpBytesReturned - Pointer to variable to receive byte count
lpOverLapped - pointer to overlapped structure

#define CTL_CODE ( DeviceType, Function, Method, Access ) (       \
                              ((DeviceType) << 16) | ((Access) << 14) | ((Function) << 2) | (Method))
DeviceType - IoControlCode 가 사용되는 디바이스 장치의 유형을 정의
Access - 해당하는 IoControlCode 와 같이 사용되는 버퍼의 방향을 명시
Function - 구체적인 수행 코드를 구분
                  MS에서 0~2047까지의 수를 예약해서 사용하므로 드라이버 개발자는 2048~4095까지의 수만
                  사용할 수 있다.
Method - 사용되는 버퍼의 사용 전략을 명시

#define IOCTL_INDEX   0x800
#define IOCTL_MY_CODE   CTLCODE(FILE_DEVICE_UNKNOWN,  \
                                                          IOCTL_INDEX,  \
                                                          MEHTOD_BUFFERED,  \
                                                          FILE_ANY_ACCESS)
...
DeviceIoControl(Device, IOCTL_MY_CODE, ...);