How to run an other application on background of our application in iOS?

I have 2 applications: application A and application B. Application B does some stuff and creates some text. And now I'm going to call B in BACKGROUND of application A and then print result of B in application A. So what should I do? Could anybody send me some pseudocodes?

Solution

If they are really app(lication)s, this is not possible due to the sandboxing of iOS. If you mean background processing, have a look on NSOperationQueue or (more low level) Grand Central Dispatch. See more about concurrency in the related Apple documentation.