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[Cs-dev] reply from FLTK people

Date2005-11-30 12:21
FromVictor Lazzarini
Subject[Cs-dev] reply from FLTK people
Here's one reply I had from the FLTK  people:

===================================================================

Yes, user interface related functions can only be called from the
main thread. This is a restriction of the operating systems that FLTK
builds upon. We have put a great deal of work into FLTK to still give
you access to the UI from child threads.

You ca call any function that does not open or close a window or
handle messages from a child thread. You must use correct locking to
do so:

In the main thread, you must call Fl::lock() before starting your
child threads. Do not call unlock anywhere in you main thread, FLTK
will do that for you.

In all the child threads, you must use the following sequence around
calls to FLTK:
Fl::lock();
// your FLTK calls
Fl::unlock();
Fl::awake(); // if you want the user interface to refresh changes

Remebre, don't call show() or hide() on top level or OpenGL windows
in a thread. Don't call flush(), wait() or run() either.

On Nov 30, 2005, at 10:44 AM, Victor.Lazzarini@nuim.ie wrote:

 > I have been working with FLTK and Csound (FLTK 1.1.6) and
 > it does not seem to be able to run in a multithreading
 > environment. FLTK is built with enable-threads.
 >
 > Basically Fl::wait() never returns if it is called from
 > a different thread than the one where FLTK library
 > objects have been created.
 >
 > Does anyone know about this?
 >
 > Victor

Looks like Fl::wait() cannot be called from a thread. This is very strange 
as the
code works elsewhere.


Victor Lazzarini
Music Technology Laboratory
Music Department
National University of Ireland, Maynooth 



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