IOCTL_STORAGE_MEDIA_REMOVAL

Using the IOCTL_STORAGE_MEDIA_REMOVAL control code enables or disables the mechanism that ejects media, for those devices possessing that locking capability.

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

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

Parameters

hDevice

[in] Handle to the object from which media is to be removed. To obtain a device handle, call the CreateFile function.

dwIoControlCode

[in] Control code for the operation. This value identifies the specific operation to be performed and the type of device on which to perform it. Use IOCTL_STORAGE_MEDIA_REMOVAL for this operation.

lpInBuffer

[in] Pointer to a buffer that contains a PREVENT_MEDIA_REMOVAL data structure.

A TRUE value for that structure's PreventMediaRemoval member specifies that media removal is prevented (the device is locked). A FALSE value specifies that media removal is allowed.

nInBufferSize

[in] Size, in bytes, of the buffer pointed to by lpInBuffer, which must be large enough to contain a PREVENT_MEDIA_REMOVAL data structure.

lpOutBuffer

[out] Pointer to an output buffer. Not used with this operation. Set to NULL.

nOutBufferSize

[in] Size, in bytes, of the buffer pointed to by lpOutBuffer. Not used with this operation. Set to zero.

lpBytesReturned

[out] Pointer to a variable that receives the actual count of bytes returned by the function in the output buffer.

If lpOverlapped is NULL (nonoverlapped I/O), lpBytesReturned is used internally and cannot be NULL.

If lpOverlapped is not NULL (overlapped I/O), lpBytesReturned can be NULL.

lpOverlapped

[in] Pointer to an OVERLAPPED structure.

If hDevice was opened with the FILE_FLAG_OVERLAPPED flag, lpOverlapped must point to a valid OVERLAPPED structure. In this case, the operation is performed as an overlapped (asynchronous) operation. If the device was opened with the FILE_FLAG_OVERLAPPED flag and lpOverlapped is NULL, the function fails in unpredictable ways.

If hDevice was opened without specifying the FILE_FLAG_OVERLAPPED flag, lpOverlapped is ignored and DeviceIoControl does not return until the operation has been completed, or until an error occurs.

Return Values

If the operation succeeds, DeviceIoControl returns a nonzero value.

If the operation fails, DeviceIoControl returns a nonzero value. To get extended error information, call GetLastError.

Remarks

The IOCTL_STORAGE_MEDIA_REMOVAL control code is valid only for devices that support removable media.

Requirements

  Windows NT/2000: Requires Windows NT 4.0 or later.
  Windows 95/98: Unsupported.
  Header: Declared in Winioctl.h.

See Also

Device Input and Output Overview, Device Input and Output Control Codes, DeviceIoControl, IOCTL_STORAGE_EJECT_MEDIA, IOCTL_STORAGE_LOAD_MEDIA, PREVENT_MEDIA_REMOVAL