The vfwscanf function is equivalent to the fwscanf function,
    except that instead of being called with a variable number of
    arguments, it is called with an argument list (ap) that has been
    initialized by va_start (and possibly with subsequent va_arg
    calls).

    If the stream pointed to by stream has no orientation, vfwscanf
    makes the stream wide-oriented.

    For more information about format and conversion specifications
    and their corresponding arguments, see the "Understanding Input
    and Output" chapter of the HP C RTL Reference Manual.