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DeviceIOControl
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 CreateFile 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 per-
formed. No specific values are defined for the dwIoControlCode 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 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 opera-
tion 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 output data for the operation. This
parameter can be NULL if the dwIoControlCode parameter specifies an operation
that does not produce output data.
. nOutBufferSize
[in] Size, in bytes, of the buffer pointed to by lpOutBuffer.
. lpBytesReturned
[out] Long pointer to a variable that receives the size, in bytes, of the data stored into
the buffer pointed to by lpOutBuffer. The lpBytesReturned parameter cannot be
NULL. Even when an operation produces no output data, and lpOutBuffer can be
NULL, the DeviceIoControl function makes use of the variable pointed to bylpBytes-
Returned. After such an operation, the value of the variable is without meaning.
. lpOverlapped
[in] Ignored; set to NULL.
. Return Values
UNO-1251G Software User Manual for WEC7
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