IOCTL_DISK_GET_DRIVE_GEOMETRY control code

Retrieves information about the physical disk's geometry: type, number of cylinders, tracks per cylinder, sectors per track, and bytes per sector.

Note  IOCTL_DISK_GET_DRIVE_GEOMETRY has been superseded by IOCTL_DISK_GET_DRIVE_GEOMETRY_EX, which retrieves additional information.

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



BOOL DeviceIoControl(
  (HANDLE) hDevice,              // handle to device
  IOCTL_DISK_GET_DRIVE_GEOMETRY, // 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 disk device from which the geometry is to be retrieved. To retrieve a device handle, call the CreateFile function.

dwIoControlCode

The control code for the operation. Use IOCTL_DISK_GET_DRIVE_GEOMETRY for this operation.

lpInBuffer

Not used with this operation; set to NULL.

nInBufferSize

Not used with this operation; set to zero.

lpOutBuffer

A pointer to a buffer that receives a DISK_GEOMETRY data structure.

nOutBufferSize

The size of the output buffer, in bytes.

lpBytesReturned

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.

lpOverlapped

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.

Return value

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

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

Examples

For an example, see Calling DeviceIoControl.

Requirements

Minimum supported client

Windows XP [desktop apps only]

Minimum supported server

Windows Server 2003 [desktop apps only]

Header

WinIoCtl.h (include Windows.h)

See also

DeviceIoControl
Disk Management Control Codes
DISK_GEOMETRY
IOCTL_DISK_GET_DRIVE_GEOMETRY_EX
IOCTL_STORAGE_GET_MEDIA_TYPES

 

 

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