I did some more checks to find the causes for the crashes and one of the things I checked was the way the instances were created and deleted:
- there are no Dtor calls on instances that weren't created before
- there is not more than one Dtor call for the same instance
- for the program crashes during a Dtor call, the instance hand't been deleted before
There were situations when I drew as much as possible without the application becoming too slow, and there were no crashes.
I built the dlls in Release mode (I installed Qt version 4.7.3 from here: qt-win-opensource-4.7.3-vs2008.exe and fixed some wrong settings in the NaroOccCore project file) and created the installer for this version of Naro. The resulting file is slightly smaller than the one built with the old wrappers. Enter Sketch doesn't work on the installed Naro, I'll fix the bug and start testing the new wrapper functionality in the installed version, as well. The good news is that the dlls are built correctly and there are no calls to VS2008-dependent dlls as it was when we previously built Naro with these wrappers.
I also tried to improve the way 'const' in being handled in the generation code - I kept the other fixes and changed only the const keyword, but there were crashes after drawing one circle. I will continue investigating this.