[LAD] [Jack-Devel] A picture...of the global mess

[Fons Adriaensen]

On Wed, May 20, 2009 at 04:43:33PM -0500, Jack O'Quin wrote:

> On Wed, May 20, 2009 at 2:38 PM, Fons Adriaensen <fons at kokkinizita.net> wrote:
>
> > You don't need this jackd. If all the IPC is in libjack, an
> > autostart request can be passed directly to jackcontrol without
> > creating a transient process.
> >
> > 1. Client uses jack_client_open() with autostart.
> > 2. Libjack doesn't find the server
> > 3. Libjack sends 'start server' to jackcontrol
> > 4. jackcontrol starts the server
> > 5. jackcontrol notifies libjack
> > 6. The jack_client_open() call proceeds.
> >
> > Between 3 and 5 the thread doing the original call
> > (i.e. the client's thread) just waits within libjack
> > for the ok/fail message from jackcontrol.
> 
> Don't forget a timeout in case the fork/exec fails and there is no message.

The fork/exec is done by jackcontrol, if it fails then
jackcontrol reports this and the entire jack_client_open()
is made to fail. A timeout is required to cover the case
that jackcontrol isn't there (but that can be tested before
the start server request), or it crashes doing the fork/exec,
but in the latter case there are bigger problems anyway.

Ciao,

-- 
FA

Io lo dico sempre: l'Italia è troppo stretta e lunga.