ASSERT (open ("/dev/null", O_WRONLY, 0600) == fd + 1);
ASSERT (dup2 (fd + 1, fd) == fd);
ASSERT (close (fd + 1) == 0);
ASSERT (write (fd, "1", 1) == 1);
ASSERT (dup2 (fd + 2, fd) == fd);
ASSERT (open ("/dev/null", O_WRONLY, 0600) == fd + 1);
ASSERT (dup2 (fd + 1, fd) == fd);
ASSERT (close (fd + 1) == 0);
ASSERT (write (fd, "1", 1) == 1);
ASSERT (dup2 (fd + 2, fd) == fd);