#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <termios.h>
#include <sys/ioctl.h>
#include <pty.h>

int main()
{
	int master, slave;
	struct termios tt;
	int val;
	char buf[1024];
	int len;

	if (openpty(&master, &slave, NULL, NULL, NULL) < 0) {
		perror("openpty()");
		exit(EXIT_FAILURE);
	}

	write(STDOUT_FILENO, "----------\n", 11);

	/* Write two messages */
	write(master, "01234\n", 6);
	write(master, "56789\n", 6);

	/* Read (Canonical Mode) */
	len = read(slave, buf, sizeof(buf));
	if (len>0) write(STDOUT_FILENO, buf, len);

	/* Rrset Canonical Mode */
	tcgetattr(slave, &tt);
	tt.c_lflag &= ~ICANON;
	tcsetattr(slave, TCSANOW, &tt);

	write(STDOUT_FILENO, "----------\n", 11);

	write(master, "ABCDE\n", 6);

	/* Read (Non-Canonical Mode) */
	len = read(slave, buf, sizeof(buf));
	if (len>0) write(STDOUT_FILENO, buf, len);

	write(STDOUT_FILENO, "----------\n", 11);

	/* Write two messages */
	write(master, "FGHIJ\n", 6);
	write(master, "KLMNO\n", 6);

	/* Set Canonical Mode */
	tcgetattr(slave, &tt);
	tt.c_lflag |= ICANON;
	tcsetattr(slave, TCSANOW, &tt);

	/* Flush buffer */
	tcflush(slave, TCIFLUSH);
	val = 1;
	ioctl(slave, FIONBIO, &val);

	/* Read */
	len = read(slave, buf, sizeof(buf));
	if (len>0) write(STDOUT_FILENO, buf, len);

	write(STDOUT_FILENO, "----------\n", 11);

	close(slave);
	close(master);

	return EXIT_SUCCESS;
}