wcsncasecmp() is the wide-character equivalent of strncasecmp(). It compares the wide-character string s1 and the wide-character string s2, but at most n wide characters from each string, ignoring case differences (towupper, towlower).
wcscasecmp() returns 0 if the wide-character strings s1 and s2, truncated to at most length n, are equal except for case distinctions. It returns a positive integer if truncated s1 is greater than truncated s2, ignoring case. It returns a negative integer if truncated s1 is smaller than truncated s2, ignoring case.