GetVolumeInformation is a Windows API function. The following is the definition of the function -

BOOL GetVolumeInformation(
    LPCTSTR lpRootPathName, 
    // address of root directory of the file system 
 
    LPTSTR lpVolumeNameBuffer, 
    // address of name of the volume 
 
    DWORD nVolumeNameSize, 
    // length of lpVolumeNameBuffer  
 
    LPDWORD lpVolumeSerialNumber, 
    // address of volume serial number 
 
    LPDWORD lpMaximumComponentLength, 
    // address of system’s maximum filename length 
 
    LPDWORD lpFileSystemFlags, 
    // address of file system flags 
 
    LPTSTR lpFileSystemNameBuffer, 
    // address of name of file system 
 
    DWORD nFileSystemNameSize  
    // length of lpFileSystemNameBuffer  
 
   );
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You could use the Win32::API module to access this Windows function.

DWORD is a long integer, which is 32-bits in size (a WORD is 16 bits).

Hope this would be of some help to you.