[fpc-devel] FPC 2.0.0 vs FPC 2.0.2 (div by zero)

Michalis Kamburelis michalis at camelot.homedns.org
Tue Mar 7 04:05:03 CET 2006

Den Jean wrote:
> Hi,
> I have a strange problem. My Qt4 demo program worked 
> fine with FPC 2.0.0, but crashes (div by zero) with FPC 2.0.2.
> Debugging shows that indeed a div by zero is done within
> the Qt4 lib. However with FPC 2.0.0 or using C++ code the library
> isn't bothered with the div by zero. When I use FPC 2.0.2 however
> it is.

Maybe it was FPC 2.0.0 bug (that was fixed in the meantime) that caused 
this SIGFPE inside qt to be ignored ? AFAIK it was always the intention 
of FPC that if used library causes a signal like SIGFPE, this signal 
*will not be ignored* and will cause our program to fail with some 

Maybe you can workaround this with Set8087CW, just like it has to be 
workarounded for OpenGL under Windows (see 
[http://www.freepascal.org/bugs/showrec.php3?ID=3955]). Just add 
"Set8087CW($133F);" at the beginning of your program (or even right 
inside qt unit initialization) and see if it helps.

(Note that I'm writing this without any knowledge of qt or your testcase 
--- I just thought that it may be helpful, sorry if it's not relevant :) ).


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