Determines whether a file is stored on a CSVFS volume, or retrieves namespace information.

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

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


To determine whether a file is stored on a CSVFS volume, simply leave the lpInBuffer parameter empty. If the file is on a CSVFS volume, the lpOutBuffer parameter will contain ERROR_SUCCESS.

To retrieve namespace information, specify a pointer to the same CSV_NAMESPACE_INFO structure that is initially empty (except for the Version member) in both the lpInBuffer and lpOutBuffer parameters. The information in that structure is filled in by the function call.


Minimum supported client None supported
Minimum supported server Windows Server 2012 [desktop apps only]
Header winioctl.h (include Windows.h)

See also