The problem is I have not fully understand why it happens. One, at runtime, it seems to get smashed, and when I execute a virtual function it goes off somewhere else and crashes. When I fix my program some more, and make them virtual again, it compiles and runs fine. My only guess is that I smashed the class somehow, but the smash is baffling, because the program works fine, it just the when I execute a virtually defined function in the class when it fails. class BadFoo() { virtual void ThisFooWillDie() { printf("Fooey!"); } void naughtyFunctionThatIsBeingWorkedOn() { printf("I will do something heinous and sinister to foo but only to Foo but it will not be obvious what it is."); } }; BadFoo fooWillBlowUp; fooWillBlowUp.naughtyFunctionThatIsbEingWorkedOn(); fooWillBlowUp.ThisFooWillDie(); CORE DUMP GAME OVER Another, is when I am linking, it complains about the vtable and won't compile. This error leaves me baffled because usually the class compiled and ran before without any problems, and I didn't change it at all. class thisFooWillNotCompile { public: virtual void thisFooMakesMeAngry() = 0; }; class thisFooIsNoGood : public thisFooWillNotCompile { public: void thisFooMakesMeAngry() { printf("I will not link I will say vtable blah blah blah and die..\n"); } }; Sorry I am vague but, if I knew why this was happening, I would be an advanced C++ programmer.One of them appears to be an error in my code, but the way it manifests itself is weird. The other is a compiler problem that I just do not know why it happens and honestly it shouldn't because the code worked fine before and is correct syntax, but it won't link. It says something about the vtable but I can't remember now what it said. It happened a week ago.

[...] I doubt that is the problem. You should use virtual destructors when deleting using a pointer so the correct destructor is called but when you know the pointer is of the correct type or you allocate the instance on the stack then the correct destructor will be called and I think the baseclass destructor(s) will be called also even if they are not virtual. --ms

Nick> I can not run gdb on my program, it won't work. The code is Nick> too hard to debug by just looking at it. The only way I can Nick> debug is to put hundreds of printf() into the code. That was Nick> how I found log( blah ) was making NAN as well. I have Nick> learned to live without a debugger, but it sucks, because I Nick> really need it. What is your problem with gdb? I have no problem debugging complex programs with it. I use the setting -ggdb3 and compile with optimization off. Immanuel -- It is a profoundly erroneous truism, repeated by all copy-books and by eminent people when they are making speeches, that we should cultivate the habit of thinking about what we are doing. The precise opposite is the case. Civilization advances by extending the numbers of important operations which we can perform without thinking about them. Operations of thought are like cavalry charges in battle -- they are strictly limited in number, they require fresh horses, and must only be made at decisive moments. -- A.N. Whitehead -- Immanuel Litzroth Software Development Engineer Enfocus Software Kleindokkaai 3-5 B-9000 Gent Belgium Voice: +32 9 269 23 90 Fax : +32 9 269 16 91 Email: Immanuell(a)enfocus.be web : www.enfocus.be ***************************************************************************

Hi all, For thos having trouble with C++, check out: http://www.parashift.com/c++-faq-lite/ This is a _very_ good FAQ! Cheers, Niels.