commctl
(void)commctl(com, TIOCM_DTR | TIOCM_RTS, DMSET);
(void)commctl(com, TIOCM_DTR, DMBIC);
static int commctl (struct com_s *com, int bits, int how);
(void)commctl(com, TIOCM_DTR, DMBIS);
(void)commctl(com, TIOCM_DTR, DMBIC);
(void)commctl(com, *(int *)data, DMSET);
(void)commctl(com, *(int *)data, DMBIS);
(void)commctl(com, *(int *)data, DMBIC);
*(int *)data = commctl(com, 0, DMGET);
(void)commctl(com, TIOCM_DTR, DMBIC); /* hang up line */
(void)commctl(com, TIOCM_DTR, DMBIS);