Question

What is technical reason(compiling,formatting stuff etc) why you can’t build iOS apps on Windows/Ubuntu with objective-c(just build it and upload it to your own iPhone, not app store)?

Answer 1

There is no technical reason, only business reasons. There once were cross-compiling tool chains to do rudimentary iOS development on Windows (and, AFAIK, Linux) but they aren’t actively developed any more since it’s a lot of work with no real benefit.

The business reason is pretty clear: Apple wants you to work on a Mac. If you don’t have one but you want to develop for iOS then Apple wants you to buy one. It makes sense for them to provide iTunes for Windows since they make money with the content, but it doesn’t make any sense at all for Apple to provide their development platform on any other OS than Mac OS X: it would increase the complexity of the whole development toolchain and overall would require a lot of additional work and thus would cost a lot of money. Plus, the support team would suddenly have to deal with people using an “alien” OS (Windows), also costing money. Apple is pretty quick to abandon what they consider old technologies: the current (early 2012) Xcode is only supported on their very latest OS, Mac OS X 10.7 Lion. On Windows, where the ancient XP is still used widely, they couldn’t do that. This would bind additional resources and thus cost even more money (and might taint the experience/feature set).

All these additional costs cannot be reasonably justified. Especially for the very first point: Apple wants you to buy a Mac. Chances are that you might stick as a customer and thus make even more money for Apple.