Flags: very useful when debugging with Instruments
There is a very nice feature in Instruments that helps you to point your loupe to a very precise spot in your code.
I am writing an app that process images captured by the camera in real-time. I am using GCD to launch different queues both in asynchronous and synchrous mode and when it is time to debug, it’s a mess. Most of the time I need to know extactly what is doing what and where something is executing.