Re: [Lmuse-developer] Libsynti

[Mathias L. <mat...@br...>]

ons 2004-02-18 klockan 10.03 skrev Werner Schweer:
> On Tuesday 17 February 2004 19:57, Mathias Lundgren wrote:
> ...
> > I noticed that the gui object is created within the Mess in organ. What
> > is the general idea about interaction between the gui and the mess?
> > Earlier, the fluidsynth Mess (synth/client/tone generator, whichever you
> > prefer) had to send messages to the gui every time it wanted to notify
> > the gui of changes. I'm considering letting the client take care of
> > updating things in the gui directly instead of having to send the gui a
> > lot of messages, if this is appropriate behaviour?
> >
> > One example could be loading a soundfont. The gui doesn't need to know
> > anything about how many fonts there are loaded, it just displays nice
> > little boxes and fields with info about channels and such. The gui
> > cannot, however, add the soundfont to the list after sending a "push
> > soundfont" msg to the synth, since there might be trouble loading the
> > font, so why not instead update the gui directly, from within the synth
> > whenever a new font is loaded instead of having to tell the gui the
> > soundfont was loaded? (This is getting so flexible I suspect I'm getting
> > confused having to figure out my own solutions instead of copying
> > them... ;-)
> 
> you have to consider that the gui and the synth run in different
> threads. The synth normally cannot call any qt library functions
> (they are not all thread safe).
> Further consider the synth runs in a _realtime_ thread. You cannot
> call any function which blocks in any way. You even cannot call
> functions which are thread safe by setting any semaphores. This
> includes malloc and of course new, delete and all library functions
> which use new/delete (all QString function i suspect).
> What you need is a non blocking interprocess communication mechanism
> between gui and synthesizer. If you want the gui to do something 
> you must tell it with a message and let the gui do gui stuff. You
> cannot do it directly.
> 
> Werner

Of course... Otherwise the lock-free ringbuffer wouldn't be of much
use.... Thanks for waking me up.

/Mathias