Retrieves the physical location of a specified volume on one or more disks.

To perform this operation, call the DeviceIoControl function with the following parameters.

BOOL DeviceIoControl(
  (HANDLE) hDevice,                        // handle to device
  IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS,    // dwIoControlCode
  NULL,                                    // lpInBuffer
  0,                                       // nInBufferSize
  (LPVOID) lpOutBuffer,                    // output buffer
  (DWORD) nOutBufferSize,                  // size of output buffer
  (LPDWORD) lpBytesReturned,               // number of bytes returned
  (LPOVERLAPPED) lpOverlapped              // OVERLAPPED structure
);

Parameters

hDevice

A handle to the volume. To retrieve a device handle, call the CreateFile function.

dwIoControlCode

The control code for an operation. Use IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS for this operation.

lpInBuffer

Not used with this operation. Set to NULL.

nInBufferSize

Not used with this operation. Set to 0 (zero).

lpOutBuffer

A pointer to a buffer that receives a VOLUME_DISK_EXTENTS structure that specifies the physical location of the disk.

nOutBufferSize

The size of the output buffer.

lpBytesReturned

A pointer to a variable that receives the size of the data that is stored in the output buffer, in bytes.

If the output buffer is less than sizeof(VOLUME_DISK_EXTENTS), the call fails, GetLastError returns ERROR_INSUFFICIENT_BUFFER, and lpBytesReturned is 0 (zero).

If lpOverlapped is NULL, lpBytesReturned cannot be NULL. Even when an operation does not return output data and lpOutBuffer is NULL, DeviceIoControl uses lpBytesReturned. After that kind of 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 is complete. 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.

lpOverlapped

A pointer to an OVERLAPPED structure.

If hDevice is opened without specifying FILE_FLAG_OVERLAPPED, lpOverlapped is ignored.

If hDevice is 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 is complete. Otherwise, the function does not return until the operation is complete or an error occurs.

Return Value

If the operation completes successfully, DeviceIoControl returns a nonzero value.

If the operation fails or is pending, DeviceIoControl returns 0 (zero). To get extended error information, call GetLastError.

A return value from GetLastError of ERROR_INSUFFICIENT_BUFFER indicates the output buffer is less than sizeof(VOLUME_DISK_EXTENTS).

A return value from GetLastError of ERROR_MORE_DATA indicates to the caller that the buffer was not large enough to accommodate the data requested, even though the output buffer was greater than or equal to sizeof(VOLUME_DISK_EXTENTS). In this event, you can make subsequent IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS calls to retrieve the remaining data.

Requirements

See Also

DeviceIoControl

VOLUME_DISK_EXTENTS

Volume Management Control Codes

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Build date: 2/4/2010