I have this problem in emacs when using it in console: when pressing C- it just inserts a space instead of invoking the set-mark function as it should. The control key works in console, as other key combination including CTRL key work (e.g C-h-b, C-x C-c).
Under X every keybinding works correctly, so I suppose it is not an emacs problem, but rather a console related one. Does anybody have an idea at least where to start to look for a solution?
edit: thanks for the links but it doesn't work either
after hitting C-h l (shows the keys input to emacs) I noticed that emacs doesn't get C-space at all, just space. But emacs still gets the other Ctrl keys combinations correctly. I am using the linux console, and as far as I know (correct me if I'm wrong) it's not an emulator: it is the terminal. Unfortunately I have no idea how to fix this annoying bug, as I find emacs very useful.