|How to read input from serial port?

I will have 2 machines hooked up via the COM1 ports.
1 machine running windows having a hyperterminal session opened and the other machine running Linux having my program running.
I want to able to type a character into the hyperterminal window and have the character displayed on the Linux machine.

Im very new to C programming but heres what i have for my program so far, just not sure how to read the input and display it:

#include <stdio.h>      /*Standard input/output definitions*/
#include <string.h>      /*String function definitions*/
#include <unistd.h>      /*Unix standard function definitions*/
#include <fcntl.h>      /*File control definitions*/
#include <errno.h>      /*Error number definitions*/
#include <termios.h>      /*POSIX terminal control definitions*/


int open_port(void)
{
      int fd; /* File descriptor for the port */

      fd = open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NDELAY);
            if(fd == 0)
            {
                  perror("open_port: Unable to open       /dev/ttyS0 - ");
            }
            else
                  fcntl(fd, F_SETFL, 0);
            
            return (fd);
}

/*Configire port*/

struct termios options;

/*Get the current options for the port*/

tcgetattr(fd, &options);

/*Set the Baud rates to 19200*/

cfsetispeed(&options, B19200);
cfsetospeed(&options, B19200);

/*Enable received and set local mode*/

options.c_cflag |= (CLOCAL | CREAD);

/*Set new options for port*/

tcsetattr(fd, TCSANOW, &options);

/*Set data bits*/

options.c_cflag &= ~CSIZE;      /*Mask the character size bits*/
options.c_cflag |= CS8;            /*Select 8 data bits*/

/*Set RAW input*/

options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);

/*Set Raw output*/

options.c_oflag &= ~OPOST;

/*Set timeout to 1 sec*/

options.c_cc[VMIN] = 0;
options.c_cc{VTIME] = 10;

/*Code to read input goes here*/

close(fd);

Can anyone advise on this?

Thanks