source: trunk/libs/newlib/src/newlib/libc/sys/sysvi386/tcline.c

#define _NO_MACROS
#include <sys/unistd.h>
#include <sys/termios.h>
#include <errno.h>

int
tcsendbreak (int fd, int dur) {
        do {
                if (_ioctl (fd, _TCSBRK, 0) == -1)
                        return -1;
        } while (dur--);
        return 0;
}

int
tcdrain (int fd) {
        return _ioctl (fd, _TCSBRK, 1);
}

int
tcflush(int fd, int what) {
        return _ioctl (fd, _TCFLSH, what);
}

/*
 * I'm not positive about this function.  I *think* it's right,
 * but I could be missing something.
 */

int
tcflow (int fd, int action) {
        struct termios t;

        switch (action) {
        case TCOOFF:
        case TCOON:
                return _ioctl (fd, _TCXONC, action);
/*
 * Here is where I'm not terribly certain.  1003.1 says:
 * if action is TCIOFF, the system shall transmit a STOP
 * character, which is intended to cause the terminal device
 * to stop transmitting data to the system.  (Similarly for
 * TCION.)
 * I *assume* that means I find out what VSTOP for the
 * terminal device is, and then write it.  1003.1 also does
 * not say what happens if c_cc[VSTOP] is _POSIX_VDISABLE;
 * I assume it should reaturn EINVAL, so that's what I do.
 * Anyway, here's the code.  It might or might not be right.
 */
        case TCIOFF:
                if (tcgetattr (fd, &t) == -1)
                        return -1;
                if (tcgetattr (fd, &t) == -1)
                        return -1;
#ifdef _POSIX_VDISABLE
                if (t.c_cc[VSTOP] == _POSIX_VDISABLE) {
                        errno = EINVAL;
                        return -1;
                }
#endif
                if (write (fd, &t.c_cc[VSTOP], 1) == 1)
                        return 0;
                else
                        return -1;
        case TCION:
                if (tcgetattr (fd, &t) == -1)
                        return -1;
                if (tcgetattr (fd, &t) == -1)
                        return -1;
#ifdef _POSIX_VDISABLE
                if (t.c_cc[VSTART] == _POSIX_VDISABLE) {
                        errno = EINVAL;
                        return -1;
                }
#endif
                if (write (fd, &t.c_cc[VSTART], 1) == 1)
                        return 0;
                else
                        return -1;
        default:
                errno = EINVAL;
                return -1;
        }
}