#include <wchar.h> int wcscasecmp(const wchar_t *s1, const wchar_t *s2);
The wcscasecmp function is the wide-character equivalent of the strcasecmp function. It compares the wide-character string pointed to by s1 and the wide-character string pointed to by s2, ignoring case differences (towupper, towlower).
The wcscasecmp function returns zero if the wide-character strings at s1 and s2 are equal except for case distinctions. It returns a positive integer if s1 is greater than s2, ignoring case. It returns a negative integer if s1 is smaller than s2, ignoring case.