IOCTL_CHANGER_GET_ELEMENT_STATUS control code
Retrieves the status of all elements or a specified number of elements of a particular type.
To perform this operation, call the DeviceIoControl function with the following parameters.
BOOL DeviceIoControl( (HANDLE) hDevice, // handle to device IOCTL_CHANGER_GET_ELEMENT_STATUS, // dwIoControlCode (LPVOID) lpInBuffer, // input buffer (DWORD) nInBufferSize, // size of input buffer (LPVOID) lpOutBuffer, // output buffer (DWORD) nOutBufferSize, // size of output buffer (LPDWORD) lpBytesReturned, // number of bytes returned (LPOVERLAPPED) lpOverlapped // OVERLAPPED structure );
A handle to the device. To obtain a device handle, call the CreateFile function.
The control code for the operation. Use IOCTL_CHANGER_GET_ELEMENT_STATUS for this operation.
A pointer to a CHANGER_READ_ELEMENT_STATUS structure.
The size of the input buffer, in bytes.
The size of the output buffer, in bytes.
A pointer to a variable that receives the size of the data stored in the output buffer, in bytes.
If the output buffer is too small, the call fails, GetLastError returns ERROR_INSUFFICIENT_BUFFER, and lpBytesReturned is zero.
If lpOverlapped is NULL, lpBytesReturned cannot be NULL. Even when an operation returns no output data and lpOutBuffer is NULL, DeviceIoControl makes use of lpBytesReturned. After such an operation, the value of lpBytesReturned is meaningless.
If lpOverlapped is not NULL, lpBytesReturned can be NULL. If this parameter is not NULL and the operation returns data, lpBytesReturned is meaningless until the overlapped operation has completed. To retrieve the number of bytes returned, call GetOverlappedResult. If hDevice is associated with an I/O completion port, you can retrieve the number of bytes returned by calling GetQueuedCompletionStatus.
A pointer to an OVERLAPPED structure.
If hDevice was opened without specifying FILE_FLAG_OVERLAPPED, lpOverlapped is ignored.
If hDevice was opened with the FILE_FLAG_OVERLAPPED flag, the operation is performed as an overlapped (asynchronous) operation. In this case, lpOverlapped must point to a valid OVERLAPPED structure that contains a handle to an event object. Otherwise, the function fails in unpredictable ways.
For overlapped operations, DeviceIoControl returns immediately, and the event object is signaled when the operation has been completed. Otherwise, the function does not return until the operation has been completed or an error occurs.
If the operation completes successfully, DeviceIoControl returns a nonzero value.
Minimum supported client
Minimum supported server
|Windows Server 2003|
- Device Management Control Codes