Re: [Haskell-cafe] GUI Program Hangs in GHCI

On Sun, Jul 3, 2011 at 9:06 PM, Jason Dagit wrote:

On Sun, Jul 3, 2011 at 8:31 PM, Alexander Solla wrote:

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On Sun, Jul 3, 2011 at 5:16 PM, Jason Dagit wrote:

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Hello,

I have a GUI program that when I compile it and run it there are no problems.  When I load it into GHCI and type, "main", it loads the main window but there are no window decorations and the program hangs to the point where I have to kill the ghci process.  You see a spinning cursor when you mouse over the window.

I don't know if this is the same issue, but it sounds like it at first glance: http://www.haskell.org/pipermail/haskell-cafe/2011-May/092029.html

Heh.  Yes, good memory!  That's a link to an email I wrote in response to Conal.  I'm looking into the issues that Conal mentions there.

So far I've discovered that there is a bug in the Objective-C part of glfw when it inits threads[1].  Fixing that bug makes it so that I can use forkIO in the compiled version of my program but I still have the bad behavior in ghci.  I think the remaining bit is that OSX (and probably windows too) makes it very hard to run your event loop on a thread other than your original thread[2].  I'm now wondering if the threading model in GHC even gives me enough control to handle this situation correctly.

My test was incorrect. Even with that fix I still can't use the threaded RTS in the compiled version. I think I understand the issue now and I'm looking for a solution in a different thread (pun intended?). Jason