[Jack-Devel] Jack server keeps playing sound after client disconnetcs

[Ralf Mardorf]

On Thu, 24 Aug 2017 11:50:23 -0700, Yuri wrote:
>On 08/24/17 10:31, Ralf Mardorf wrote:
>> seemingly jackaudio.org was down, so consider to resend your concerns
>> to the mailing list, since it's up again. I'm not a jackd developer,
>> just a user and simply try to point out, that Ctrl+C isn't a shortcut
>> that ensures a specific action of an application. You seem to assume
>> that Ctrl+C does kill an app or something similar, but actually an
>> app is free to continue running or to do anything else.  
>
>
>No, I am not assuming this. Ctrl+C, of course, doesn't guarantee a 
>particular action. I am just pointing out that in case of a 
>client-server architecture, which is the case here, server can't rely
>on the client to always take a particular action before disconnecting.
>It is a much more sound strategy to always clean up after
>disconnecting client regardless of what the client did.
>
>
>So, you are saying that all OSes suffer from this problem, not only 
>FreeBSD? One client I observed this recently with is 'sclang' from 
>SuperCollider.

Hi,

I don't know, I'm on Linux, but don't use Ctrl+C to exit an app
launched by command line, that is a jackd client. Either I'm using the
apps regular options to exit or if something should go wrong, I'm using
a script to send all apps that are part of a jackd session, including
jackd, a SIGKILL, before the same script restores the jackd session.
IMO a sound server aimed for real-time usage should assume that clients
do the right thing. Much likely the sound architecture of FreeBSD isn't
that reliable for a real-time audio sound server as ALSA in combination
with the Linux kernel's real-time capabilities is. Actually I don't
understand the problem. Why do you sent a SIGINT to an app? What is
done by the app, after receiving the SIGINT? I don't know what jackd
does or should do. The strategy you mentions might be right or wrong,
however, using Ctrl+C IMO is asking for trouble, since we seldom know
what action does follow.

Regards,
Ralf