towlower - convert a wide character to lowercase
wint_t towlower (wint_t wc);
The towlower function is the wide-character equivalent of the
tolower function. If wc is a wide character, it is converted to
lowercase. Characters which do not have case are returned unchanged. If
wc is WEOF, WEOF is returned.
The towlower function returns the lowercase equivalent of wc, or
WEOF if wc is WEOF.
ISO/ANSI C, UNIX98
The behaviour of towlower 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