[Visualpython-users] Lock trouble

[Bruce S. <Bru...@nc...>]

Upon updating Ubuntu Linux to the latest version I find that something 
has changed in the environment to produce a problem in the beta version 
of Visual. The rendering thread (the code that generates the OpenGL 
display) has to lock out the computational thread (your own Python code) 
in order to avoid conflicts in reading or writing common resources. The 
rendering routine for faces (in faces.cpp) tries to acquire the lock and 
fails, hanging forever, while the computational thread goes merrily on 
its way forever. Because faces are used to draw vertical and horizontal 
bars in the graph package, bar graphs hang. Oddly, if the faces are 
inside a frame, there is no problem.

The good news is that the problem is absolutely reproducible, on several 
different computers including computers with brand new clean installs of 
the latest Ubuntu. The bad news is that I haven't had much time to 
devote to the problem and don't know its cause, and I don't have 
experience debugging a thread lock problem. I would welcome suggestions.

Bruce Sherwood