Virtual Terminals in C++

Anno · 06-18-2006, 02:38 PM

This is my first post and this forum looks like
the place I would get an intelligent answer.

I would like to know where to look for info on
programming Vtty's in C++. Meaning how to go about
opening one within C++ and redirecting their
STDIN/STDOUT/STDERR.

So as can be seen. I would like to open a vtty,
execute a shell in the new-vtty and communicate
with the STDIN/OUT&ERR.

Thanks!

taylor_venable · 06-19-2006, 08:57 AM

I'm not sure I can help, but I think some more information would be useful if I could. What exactly do you mean by "virtual terminal"? You mean like the virtual terminals provided by most Unix systems and accessible via the function keys from the console (text-mode)? Or do you mean a pseudo-terminal like xterm? What's the goal / purpose of your program?

I think you're working through three levels of abstraction / execution here: (1) terminal (2) shell (3) user's commands. If what I understand about your goals is correct, my "programmer's intuition" says this is going to be pretty hard.

First, I believe the shell's standard input comes from the terminal, which knows how to interpret keystrokes delivered to it either from the keyboard driver via the kernel, or from the X window system. Second, if you try to redirect this stream, the shell won't get it, in which case there's no point in having a shell at all. Maybe you want to duplicate the file descriptor so both you and the shell can get the input from the terminal. The same goes with the output and error streams, if you want those to actually show up on the screen.

Anno · 06-20-2006, 01:26 AM

Thanks for the reply. And yes, you do bring up some valueble points.

Quote:

Originally Posted by taylor_venable

Or do you mean a pseudo-terminal like xterm? What's the goal / purpose of your program?

The task was givin to me to write an "ssh-like" program that runs straight over TCP-IP connections. And will later be able to call X-applications.
That is why I'would like to redirect the display (STDOUT) and make it possible to change the STDIN to not come from the keyboard, but from another source, example the connection setup between the two systems.

I did a bit of searching and it would seem that I'm looking at working with pseudo-terminals. As it sould not have to be a tty.