A cross-platform Internet reachability addon. Register listeners on ofxReachability::connectedEvent and ofxReachability::disconnectedEvent and you're good to go.
The Apple implementation uses Reachability by Tony Million. Works on Mac and iOS.
The Windows implementation is based on this article by Raymond Chen.
Other platforms use the ping implementation, where I just ping google.com at regular intervals. Specific platform implementations are welcome!
Drop the ofxReachability folder into openFrameworks/addons/.
When adding the files to your project, make sure to include the "apple" subfolder on Mac / iOS, and the "win32" subfolder on Windows.
If you're on Mac, you'll also need to add SystemConfiguration.framework in the linking build phase.
Tested with openFrameworks 0.8.4 on Mac OS X 10.10 and Windows 8.1.