Advantech SPC-57 - Manual (Page 75)

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This function sends a control code directly to a specified device driver, causing the
corresponding device to perform the specified operation.
BOOL DeviceIoControl(
HANDLE hDevice,
DWORD dwIoControlCode,
LPVOID lpInBuffer,
DWORD nInBufferSize,
LPVOID lpOutBuffer,
DWORD nOutBufferSize,
LPDWORD lpBytesReturned,
LPOVERLAPPED lpOverlapped) ;
- Parameters
hDevice
[in] Handle to the device that is to perform the operation. Call the Create- File function to obtain a
device handle.
dwIoControlCode
[in] Specifies the control code for the operation. This value identifies the specific operation to be
performed and the type of device on which the operation is to be performed. No specific values are
defined for the dwIo- ControlCode parameter. However, the writer of a custom device driver can define
IOCTL_XXXX control codes, per the CTL_CODE macro.
These control codes can then be advertised, and an application can use these control codes with
DeviceIoControl to perform the driver-specific functions.
lpInBuffer
[in] Long pointer to a buffer that contains the data required to perform the operation.
This parameter can be NULL if the dwIoControlCode parameter specifies an operation that does not
require input data.
nInBufferSize
[in] Size, in bytes, of the buffer pointed to by lpInBuffer.
lpOutBuffer
[out] Long pointer to a buffer that receives the operation's output data.