The fwprintf function writes output to the stream pointed to by
    stream under control of the wide-character string pointed to by
    format, which specifies how to convert subsequent arguments to
    output. If there are insufficient arguments for the format, the
    behavior is undefined. If the format is exhausted while arguments
    remain, the excess arguments are evaluated, but are otherwise
    ignored. The fwprintf function returns when it encounters the end
    of the format string.

    The format argument is composed of zero or more directives that
    include:

    o  Ordinary wide characters (not the percent sign (%))

    o  Conversion specifications