How to set DISPLAY in my workspace



I was trying to install the plugin to test a simple OpenGL application. If we can develop simple OpenGL or SFML graphical applications that have a display window, then Cloud9 would be a perfect platform for our educational purposes.

In trying to install the plugin, I received the same error that was posted to the github account (

jpaone:~/plugin/c9.ide.desktop (master) $ c9 install c9.ide.desktop --force
Unknown Error getting

Is this an error on the Cloud9 side or the plugin side?


From the comments for c9.ide.desktop, I found another solution that I can confirm worked for me.

Instead of using c9.ide.desktop, the cloud9-vnc worked great straight out of the box. There was a little bit of setup I needed to do to install some dependencies, but once those were installed it worked great. I was able to successfully run an OpenGL application in the new desktop.

Here are the steps I needed to do to install on a clean workspace.

To install cloud9-vnc:

cd ~
mkdir plugins
cd plugins
git clone
cd cloud9-vnc
sudo ./

To install all the dependencies:

sudo apt-get update
sudo apt-get install supervisor
sudo apt-get install x11vnc
sudo apt-get install xvfb
sudo apt-get install fluxbox
sudo apt-get install novnc

To start the vnc client:


There is also an option to use the custom C9 runner that is installed

Run > Run With > C9vnc

C9.ide.desktop not working
Running Python that uses turtle in c9?
Problem with Gosu tutorial: Could not initialize SDL, No available video device

Okay, I did all that. But still getting that "freeglut (./a.out): failed to open display ‘’. Is there a way to run an OpenGL executable?


So do you have OpenGL C program executing in your Cloud9 box?