January 2002 - HOpenGL

RE: [HOpenGL] news on FFI?
by Simon Marlow 05 Feb '02

05 Feb '02

> > I would like to know if that will help to solve that > "uncaught exception > > problem" when leaving HOpenGL programs. > > A strictly conforming implementation shouldn't have that problem, see: > > http://haskell.org/pipermail/ffi/2002-January/000436.html > > I know that Simon "RTS" Marlow :-) is on this list, what... who.. me? :-} > so perhaps he could answer > the question when GHC is changed this way... Ok, the problem as we all know is that System.exitWith now raises an exception rather than simply terminating the program. This is highly desirable behaviour especially in a concurrent system, and was essential in GHCi so that if the interpreted program calls System.exitWith we don't terminate GHCi itself. The problem is that this exception isn't propagated to the main thread automatically if it is raised in a child thread. Foreign-exported functions are run in child threads. Furthermore, it's not clear exactly how the exception should be propagated, because there isn't always a single main thread to send it to. Two workarounds spring to mind: firstly, you could wrap callbacks in a suitable exception handler. So instead of calling 'mkCallback e' where mkCallback is a foreign export dynamic, you would call 'mkCallback (Exception.catch e handler)' where handler is something like topHandler in fptools/ghc/lib/std/PrelTopHandler.lhs, but you probably want to discard all exceptions except ExitException. Perhaps GHC should do this wrapping automatically, I'm not sure. Alternatively you could call your own version of exitWith which does a real exit. Again, see PrelTopHandler.lhs for the function shutdownHaskellAndExit, which is our equivalent of hs_exit() (when we get around to catching up with the FFI spec, hs_exit() will probably be a synonym for shutdownHaskellAndExit()). Cheers, Simon

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mainloop & return
by Andre W B Furtado 03 Feb '02

03 Feb '02

Is there any problem if the same function that calls "mainloop" returns a value? Ex.: main :: IO () main = do msg <- startGL putStrLn msg startGL :: IO String startGL = do -- init GLUT -- create window -- declare callback procedures mainloop return "ok"

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news on FFI?
by Andre W B Furtado 24 Jan '02

24 Jan '02

Hi. I heard Manuel released a new FFI Addendum. I would like to know if that will help to solve that "uncaught exception problem" when leaving HOpenGL programs. -- Andre

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Open GL
by Nicolas Oury 06 Jan '02

06 Jan '02

I am very interested in OpenGL under Haskell and I am wondering if there re a way I could be usefull. By the way, I have a small and ugly (very dirty, no configure, no documentation) binding of wht in SDL library can be used to get read of GLUT ( I think callback aren't very easy o use in a functionnl way. I can make it cleane and put it on a web page if anyone is interested. Make me know. I wonder if there is any preversion simulating the draft version of OpenGL 2.0 on which one could work to be ready when the standard move. Best Regards, Nicolas Oury

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compilation problems
by Shuying Wang 05 Jan '02

05 Jan '02

Hi, I've just joined the list and have looked through the backlog of emails but I don't see anyone who's had my problems. Just a few questions... I would like to know what @green_card_comma@ does, as that generated an error in GLUT_Init.gc when I ran make depend. Replacing "@green_card_comma@" with "," seems to resolve it. Also, I have glut3 but code pertaining to glut4.x wasn't commented out? I had a look at configure.in and under " Test GLUT Xlib implementation", I think something like else glut_geq_4_9="-- " glut_geq_4_11="--" glut_geq_4_13="-- " is missing? Then I ran make, and I got the following error: /usr/bin/ghc -syslib lang -split-objs -odir GL_Errors -fglasgow-exts -I/usr/X11R6/include "-#include <GL/glut.h>" -recomp -Wall -O -c GL_Errors.hs -o GL_Errors.o /tmp/ghc6071.hc: In function `s2n5_ret': /tmp/ghc6071.hc:295: `GLU_INCOMPATIBLE_GL_VERSION' undeclared (first use in this function) /tmp/ghc6071.hc:295: (Each undeclared identifier is reported only once /tmp/ghc6071.hc:295: for each function it appears in.) /tmp/ghc6071.hc: In function `GLzuErrors_zdwunmarshallzuError_fast1': /tmp/ghc6071.hc:654: `GLU_INCOMPATIBLE_GL_VERSION' undeclared (first use in this function) make[1]: *** [GL_Errors.o] Error 1 And I'm not sure what I'm missing. Can someone please help me? I tried installing HOpenGL-1.01 with gc-2.03 and ghc-5.02 under debian (woody). thanks, Shuying

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Website has moved
by Sven Panne 04 Jan '02

04 Jan '02

The HOpenGL web site has moved to haskell.org, its new URL is: http://haskell.org/HOpenGL Apart from cosmetic changes, it now contains * version 1.01 again, which seems to have disappeared after a server crash at the previous site >:-( * a short description of HOpenGL's future * a list of bugs and patches for SGI's OpenGL .spec files Have fun, S.

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