What happens if I don't pass a pCreateExParams to CreateFile2?

The final pCreateExParams parameter to the CreateFile2 function is optional. What happens if I pass NULL?

If you pass NULL as the pCreateExParams parameter, then the function behaves as if you had passed a pointer to this structure:

CREATEFILE2_EXTENDED_PARAMETERS defaultCreateExParams =
{
 sizeof(defaultCreateExParameters), // dwSize
 0, // dwFileAttributes
 0, // dwFileFlags
 0, // dwSecurityQosFlags
 NULL, // lpSecurityAttributes
 NULL, // hTemplateFile
};