terminate thread waiting on cin

I'm using Boost to run a couple of threads, one of which reads commands
via std::cin and another receives them through a socket. It's entirely
possible that during the life of the app, all commands will be sent
through the socket and the thread watching cin will never "see any
action". So the problem is, how do I terminate this thread that waits
for keyboard input?

Unfortunately, Boost::thread doesn't yet allow me to force the thread
to terminate. Even after I exit main(), the app doesn't die until
something is entered via cin. I'm trying to keep the code
cross-platform compatilible so I'd like to avoid any OS-specific
gobledigook.

Any ideas?
Nothing definitive. Terminating a thread is generally an extremely bad
idea. You could close the file handle/file descriptor of cin/STDIN, and
it should stop the read. But that's OS specific.

Assuming just one thread can use cin, why not run the ui in the main thread?
Thanks in advance!