[ianstallings]

Although it's not a true "pipe", the best way to handle data transfer between apps on iOS is to use custom URL schemes. I've done this to pass data and launch another application.

See "communicating with other apps": https://developer.apple.com/library/ios/documentation/iPhone...

In one app framework we built we had a fairly complicated parser and it could handle a pretty wide variety of URL paths and the supplied data. But there in turn lies the problem - each app must have a mechanism to handle the parsing and routing for these URLs.

[rcoh]

This is a good start -- http://x-callback-url.com/ is a standard and listing for apps that support it. The biggest problem is that there is a limited amount of data that you can transfer in a URL (about 80KB I believe) so even large PDFs will start to cause problems.