Re: [Jack-Devel] netjack audio routing from smart OSs (IOS and Android)

On Thursday 26 March 2015 15:01:32 Ralf Mardorf wrote:
> A long time ago, when jack didn't crash on that iPad, there were quasi
> no jack clients available.

That's the list of apps that support(ed) JACKiOS:

	http://www.crudebyte.com/jack-ios/apps/

In the meantime I got response from Apple engineers, and they clearly stated 
that the IPC mechanism used by JACKiOS (POSIX shm & POSIX semaphores) was from 
their perspective not intended to exist on iOS (iOS and OS X share a major 
part of kernel, drivers and API code) and that they disabled that IPC 
mechanism starting with iOS 7, because it was "a bug".

I have to note though, that the CFMessagePort API is still available as a 
primitive way of IPC on iOS. You have to know though how to use it exactly in 
order that it works on iOS 7 and higher. It seems to me as if Apple engineers 
intentionally left the CFMessagePort API available (in a constrained way) so 
that the "Audiobus" app continues to work, which became quite popular for 
audio interconnection between apps on iOS.

Unfortunately the CFMessagePort API is not a real alternative for JACK. We 
would need to rewrite a major part of JACK(2) so that it would work with 
CFMessagePort and in the end you would have all the drawbacks and 
inefficiencies of Audiobus, including loss of SMP support, latencies issues 
and so on. So IMO it is not worth the effort. And in the end, even if someone 
would put efforts in "fixing" JACK on iOS this way, you'll never know if Apple 
engineers react with a next update of iOS by putting a new spoke into your 
wheels.

CU
Christian

1427380101.14269_0.ltw:2, <201503261428.21217.schoenebeck at crudebyte dot com>