/** evaluates to 1 if x < y, to -1 if x > y and to 0 if x == y */
#define NUM_COMPARE(x, y) ((int)((x) < (y)) - (int)((x) > (y)))
/** evaluates to 1 if x < y, to -1 if x > y and to 0 if x == y */
#define NUM_COMPARE(x, y) ((int)((x) < (y)) - (int)((x) > (y)))