Defined in header
wint_t towupper( wint_t ch );
Converts the given wide character to uppercase, if possible.
|ch||-||wide character to be converted|
Uppercase version of
ch or unmodified
ch if no uppercase version is listed in the current C locale.
Only 1:1 character mapping can be performed by this function, e.g. the uppercase form of 'ß' is (with some exceptions) the two-character string "SS", which cannot be obtained by towupper.
C++ documentation for towupper