问题
After I installed XCode 6 GM, application, compiled by it started to return nil at Metal Framework device.newDefaultLibrary() call. What's the problem?
回答1:
Update your device to iOS 8 GM and it will stop failing.
回答2:
Try use - (nullable id )newDefaultLibraryWithBundle:(NSBundle *)bundle error:(__autoreleasing NSError **)error
来源：https://stackoverflow.com/questions/25757157/device-newdefaultlibrary-returns-nil