Three20.info. Rory Lewis, KDD, iPhone and iPad Apps, Epilepsy Prediction, Bachelor of Innovation, Zbigniew Ras, Andrzej Skowron, Immanuel Kant, Rough Set Theory, Fuzzy Logic, Genetic Algorithms, iphone and iPad Apps for Absolute Beginners, Sex, Religion, God and Music. iOS Debugging Magic. Technical Note TN2239 iOS contains a number of 'secret' debugging facilities, including environment variables, preferences, routines callable from GDB, and so on. This technote describes these facilities. If you're developing for iOS, you should look through this list to see if you're missing out on something that will make your life easier. Introduction. Cocos2d-iphone - Project Hosting on Google Code.