Connecting to stdin and stdout

Hello all,

I have a freeware program that is used as a graphical interface for
dos-chessprograms. The interface program starts the dosprogram, and when the
dosprog. writes to the screen, the graphprg. catches this and shows it on
his board.
I guess it is doing this by redirecting the std- in and out.

Now I want my windowsprogram inside this interface. How do I exchange
information ? I've tried sockets, pipes, streams etc. nothing. Do gui
programs have a std- in or out ? If not, what does the other program connect
to ? It doesn't give an error so it connects to something.
Any help, or example is very welcome.