serial port communication

[infineonintern]

Hello everyone, i need help. I am new to serial port programming and C++ programming. I need to allow two PCs to communicate through serial port and they are connected via null modem cable. I have done the basic of opening, setting parameters, timeouts and stuff to the port in my program. If i want to allow whatever which is typed on computer A to be seen on computer B, how do i do it? Im stucked here, hope someone can help, thanks a lot!