CLOCK_SECOND
if (clock_gettime(CLOCK_SECOND, &tt) < 0)
case CLOCK_SECOND:
if (clock_id == CLOCK_SECOND)
case CLOCK_SECOND:
case CLOCK_SECOND:
case CLOCK_SECOND:
clockid == CLOCK_SECOND;
case CLOCK_SECOND:
case CLOCK_SECOND:
case CLOCK_SECOND: