Docker exec command not giving output of /dev/pts redirection command


I am running docker exec command for a running container to run a command like this

docker exec -it /home/root/program

Console dev: /dev/pts/5

Which is redirecting to /dev/pts console and not giving any output. This program is like gdb where we take input and show some output.

and even when I try running docker attach command it hangs . I am using docker 1.12.0-dev branch.

Please let me know where could be the problem as I am new to docker.