Author: Julia Lawall <Julia.Lawall@lip6.fr> TRIG_ROUND_NEAREST is 0, so a bit-and with it is always false. The value TRIG_ROUND_MASK covers the bits of the TRIG_ROUND constants, so first pick those bits and then make the test using ==. The same is done for TRIG_ROUND_UP for symmetry, even though bit-and would be sufficient in this case. This …