I am trying to use MobileSubstrate to have a socket listening on a port on various UIKit applications. However, when my extension hooks into MobileSafari, MobileMail or MobileMaps, it is unable to successfully create the socket. I found this page on the iPhone Dev Wiki which clarifies the issue: http://iphonedevwiki.net/index.php/Seatbelt .
Is there any way around this for the built in applications to be able to listen on a socket (or open one at all?) If not, what's another good (and easy) way to do interprocess communication on iOS?
Personally for inter-device communication, i use CFMessagePorts which are a lot like mach ports. http://developer.apple.com/mac/library/documentation/CoreFoundation/Reference/CFMessagePortRef/Reference/reference.html
If all you need is notifications - no data, then i'd suggest looking at the Darwin Notification Center (based off of CFNotificationCenter)