The State Preservation and Restoration system is well documented here: Preserving Your App’s Visual Appearance Across Launches.
But what is not well known is that there is a secret preference to enable debug logs.
Apple introduced in iOS 7.0.3 a setting to reduce motion ( http://support.apple.com/kb/HT5595 ) : Settings -> General -> Accessibility -> Reduce Motion
Sadly there is no public API to know if the user enabled “Reduce motion”.
Here are different solutions to display automatically a backtrace when entering a specific function in your application. As an example we will take the following program. It’s a really simple program: the main function calls the function function1 which prints a string.