towupper - convert a wide character to uppercase
wint_t towupper (wint_t wc);
The towupper function is the wide-character equivalent of the
toupper function. If wc is a wide character, it is converted to
uppercase. Characters which do not have case are returned unchanged. If
wc is WEOF, WEOF is returned.
The towupper function returns the uppercase equivalent of wc, or
WEOF if wc is WEOF.
ISO/ANSI C, UNIX98
The behaviour of towupper depends on the LC_CTYPE category of the current
This function is not very appropriate for dealing with Unicode
characters, because Unicode knows about three cases: upper, lower and title