Thanks Bernd Strieder ! i've tried like this already.
<code> $ g++ -o test test.cpp -Wall -ansi -pedantic" </code> i didn't see any warning. but, i'm tring use let me known optimizing option "-O2" and i can see warning from g++ exactly. <code> $ g++ -o test test.cpp -Wall -ansi -pedantic -O2" test.cpp: In function `int main()': test.cpp:5: warning: 'str' might be used uninitialized in this function </code> so, cause i could see warning from VC++ 6.0, it has an optimizing option already. Thanks. Regards, godmode2k at hotmail.com from KLDP.org "Bernd Strieder" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] >h wrote: > >> Thanks Mehturt. >> >> but, it works through g++ on Cygwin and GNU/Linux machine without >> MS-VC++ 6.0 on win32 machine. >> i know i've attached code are has a problem. >> >> okay, i wanna know exactly attached code are why looks working good in >> g++ only. >> that's it. > > I cannot reproduce the exact behaviour. The app crashes at different > places depending on optimization. > > If you compile with optimization and warnings turned on, then g++ will > tell you something (g++ -O2 -Wall ...). If you want to know exactly > what happens, you have to use a debugger to look what the values are > initialized to. Or you have to insert some more output. But don't be > surprised, if behaviour changes completely, when you do so. This is the > very nature of undefined behaviour, it can be like a phantom. You have > done a simple bug and it will bug you for weeks, randomly. This is why > it is so nice that the compiler can warn you about missing > initializations. > > I think it is prossible to create both kinds of apps with undefined > behaviour on all platforms, non-crashing and crashing ones. The > differences are subtle, and you have to dig deeply into the whole > runtime system to understand. You need about the expertise a hacker > uses to break into some application. > > There is no point in looking for the exact cause, that undefined > behaviour does not result in a crash, just remove the bug and be happy, > and remember next time you declare a pointer to initialize, and > remember to turn warnings on next time you compile. > > Bernd Strieder > _______________________________________________ help-gplusplus mailing list help-gplusplus@gnu.org http://lists.gnu.org/mailman/listinfo/help-gplusplus
