Calling of GetVolumeInformation returns empty serial number

[Durumdara]

Hi!

Windows 10, Python 3.6.

I want to get the serial number of the drives (without external modules
like Win32 or WMI).
It is needed for identification of removable devices (like USB external
drives).

Somewhere I saw this code:

def GetVolumeID(Drive):
    import ctypes
    kernel32 = ctypes.windll.kernel32
    volumeNameBuffer = ctypes.create_unicode_buffer(1024)
    fileSystemNameBuffer = ctypes.create_unicode_buffer(1024)
    serial_number = None
    max_component_length = None
    file_system_flags = None

    rc = kernel32.GetVolumeInformationW(
        ctypes.c_wchar_p(Drive),
        volumeNameBuffer,
        ctypes.sizeof(volumeNameBuffer),
        serial_number,
        max_component_length,
        file_system_flags,
        fileSystemNameBuffer,
        ctypes.sizeof(fileSystemNameBuffer)
    )
    return serial_number;

print(GetVolumeID('c:\\'))


This function is working with other values (volumeNameBuffer), but for
serial  it returns None.
The serial number is empty.
How to I pass this parameter to I get the value?

The doc said it's LPDWORD (pointer to DWORD):

https://msdn.microsoft.com/en-us/library/windows/desktop/aa364993(v=vs.85).aspx

_Out_opt_ LPDWORD lpVolumeSerialNumber,


Thank you for any advance in this theme!

Best wishes
   dd