Csound Csound-dev Csound-tekno Search About

Re: Standalone FLTK exe's from Lettuce

Date2006-05-01 22:46
FromVictor Lazzarini
SubjectRe: Standalone FLTK exe's from Lettuce
My suggestion: I would not waste my time trying
to get FLTK to work on a multi-threaded application.
It will most likely fail (esp on Windows). The FLTK
developers already said that the way Csound implements
FLTK when doing it in a separate thread is not guaranteed
to work. Csound can also implement it on a single thread,
and that is the correct way of doing things as prescribed
by the FLTK model. However this will again be liable to
fail if the csound lib is used in a multi-threaded
application. In order for it to work with no issues, it will
have to be single-threaded, if multi-threading is used
all FLTK code has to run on the main/parent/starting thread.

This path has been threaded by John Ramsdell and then
by myself, independently, reaching similar dead-ends and
the conclusion is: don't bother.

While multithreading works on Linux, Windows and OSX 10.3
with the 'classic' command-line frontends, this is just
an accident and might stop working in the future.
With frontends that are themselves multithreaded, things
get more problematic and that's why Lettuce has these
problems with FLTK widgets.

You can debug, but you'll see that the source of the
problem will most likely be FL::wait().

Victor

>
> Rory Walsh wrote:
>
> > ... probably the root to my problem is that when I stop
> > Csound from  Lettuce the fltk panel remains open, hence
> > when I re-run the  instrument it's not surprising that I
> > get errors. I'm working with the  Borland C++ debugger.
> > I'd like to know more about the threading issues  with
> the fltk opcodes. Are there any preprocessor commands I
> > can  include that may sort it out?
>
> Alas, I'm too far from Windows these days, but perhaps I
> can offer a  hint. You'll need a debugger capable of
> illustrating the separate  threads so you can see
> where/why the FLTK panel stays open. Maybe  there's a
> setting for the Borland debugger ?
>
> Can you run the executable from the debugger ? If so, run
> a backtrace  from the error point and post the results.
> Istvan and Michael can  certainly help you more than I
> can. I am not a programmer, and C++  really leaves me in
> the dust. :)
>
> Best,
>
> dp
>
> --
> Send bugs reports to this list.
> To unsubscribe, send email to
> csound-unsubscribe@lists.bath.ac.uk

Date2006-05-01 22:55
Fromschwaahed
SubjectRe: Standalone FLTK exe's from Lettuce
AttachmentsNone  

Date2006-05-01 22:59
FromDave Phillips
SubjectRe: Standalone FLTK exe's from Lettuce
Victor Lazzarini wrote:

>My suggestion: I would not waste my time trying
>to get FLTK to work on a multi-threaded application.
>It will most likely fail (esp on Windows).
>
I forgot to mention that Victor can probably help too. :)

(Hi Victor! How was LAC this year ?)

Best,

dp