[fpc-devel] OpenGL and glut bugs in Freepascal 2.1.1runningwith Mac Os X Tiger ?
nexus at gmx.net
Fri Nov 4 22:23:26 CET 2005
----- Original Message -----
From: "Adriaan van Os" <fpc at microbizz.nl>
To: "FPC developers' list" <fpc-devel at lists.freepascal.org>
Sent: Thursday, November 03, 2005 10:48 AM
Subject: Re: [fpc-devel] OpenGL and glut bugs in Freepascal 2.1.1runningwith
Mac Os X Tiger ?
> Nexus wrote:
>> An unhandled exception occurred at $903E68B8 :
>> EInvalidOp : Invalid floating point operation
>> So it first seems to be some error in the fpu code generation of the
>> compiler. But the strange things is, after running a C-Program which uses
>> glut and open gl everything just works fine. So maybe there is something
>> wrong in the open gl / glut initialization part or some incompatibilities
>> with Mac OS X 10.4
> Just a guess - could this be the same problem as discussed in the
> "[fpc-devel] MacOSX: EXC_ARITHMETIC in PerformHIConversion" thread, where
> Jonas Maebe wrote:
>>>>> Are these exceptions by default disabled by gcc ?
>>>> The FPC runtime explicitly turns them on by default (since they are
>>>> required for detecting errors), while libc doesn't. It is independent
>>>> of the compiler used.
>>> So, if I understand it correct, you wont get a aritmic exeption in FPC
>>> anymore when this is turned on ?
>> The "invalid fpu operation" exceptions are turned on in the FPC system
>> unit initialisation code. If you add the code I posted, they are turned
>> off again and so you won't get them (not due to buggy code in the Carbon
>> framework and not anywhere else either).
> Adriaan van Os
> fpc-devel maillist - fpc-devel at lists.freepascal.org
Thank you very much for your help (all of you).
You were absolutely right. It seems to be the same problem as discussed in
the "[fpc-devel] MacOSX: EXC_ARITHMETIC in PerformHIConversion" thread.
I ran the programs with Mac OS X 10.3 and they were running just fine. They
just crash with Mac OS X 10.4.x.
It seems to be the same bug in the Carbon framework under Mac OS X 10.4.x
mentioned in this thread, which causes to generate invalid floating point
operation exceptions in some cases. By disabling these exceptions as
mentioned in the EXEC_ARITHMETIC thread with
everything works now with Mac OS X 10.4 as it should.
But two questions remain:
1.) Why are the fpc applications running fine after running some open gl
applications written in c ? (maybe i didn't get it yet, sorry)
2.) It does not sound very safe to turn of the floating point exceptions
forever (or at least until Mac OS X 10.5). Is there any possibility to
create some clean workaround without needing the divine intervention of the
apple fixing the carbon libs in 10.4 ?
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