function is the wide-character equivalent of the
If wc is a wide character, it is converted to
Characters which do not have case are returned unchanged.
If wc is WEOF, WEOF is returned.
function returns the lowercase equivalent of wc,
or WEOF if wc is WEOF.
The behavior of
depends on the
category of the
This function is not very appropriate for dealing with Unicode characters,
because Unicode knows about three cases: upper, lower and title case.