diff --git a/mingw-w64-headers/include/wchar.h b/mingw-w64-headers/include/wchar.h
index 83b7f5a..5b5c1d0 100644
--- a/mingw-w64-headers/include/wchar.h
+++ b/mingw-w64-headers/include/wchar.h
@@ -876,7 +876,7 @@
     if (_N == 0 || _S1 == _S2)
       return 0;	/* even for NULL pointers.  */
     if ((_S1 && !(_S2)) || (_S2 && !(_S1)))
-      return _S2 ? 1 : -1; /* robust.  */
+      return !(_S2) ? 1 : -1; /* robust.  */
     for ( ; 0 < _N; ++_S1, ++_S2, --_N)
       if (*_S1 != *_S2)
 	return (*_S1 < *_S2 ? -1 : +1);