[Haskell-cafe] Threads freezing

Eitan Goldshtrom thesourceofx at gmail.com
Sun Apr 25 10:16:18 EDT 2010

Hello fellow Haskell programmers,

I seem to be having problems with some threads of mine. I wrote an 
OpenGL program that employs some threads (forkIO) in order to separate 
any calculations from the OpenGL code. At first it all seemed to be 
working just fine. Then I added some code for keyboard input to reset 
the program when you press 'r'. Since then my threads have been giving 
me problems. Just a second after the program starts all the calculations 
stop. The program is still running the code to display graphics (I 
tested this by putting "putStrLn "still displaying" into the display 
function) but the threads that do all of the computation don't seem to 
return from their threadDelay, which is only a delay of 5000 
microseconds. I tried getting rid of the code for keyboard input but the 
problem is still there. I tried to run the program on another computer 
and it ran just fine (without keyboard input). Does anyone have any idea 
what could be going on?

Additionally, I just tried compiling it to an executable and it seems 
that when I run it from that it works fine, with the keyboard input too. 
So I'm guessing the problem is with the interpreter? I'm not really 
sure. Haskell is still pretty mysterious to me.

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