Defined in header
wint_t towlower( wint_t ch );
Converts the given wide character to lowercase, if possible.
|ch||-||wide character to be converted|
Lowercase version of
ch or unmodified
ch if no lowercase version is listed in the current C locale.
Only 1:1 character mapping can be performed by this function, e.g. the Greek uppercase letter 'Σ' has two lowercase forms, depending on the position in a word: 'σ' and 'ς'. A call to towlower cannot be used to obtain the correct lowercase form in this case.
C++ documentation for towlower