[ghemical-devel] Re: redhat 9 g++ has no dynamic_cast problems

[Tommi Hassinen]

On Tue, 15 Apr 2003, Michael Banck wrote:

> > [thassine@shrike thassine]$ g++ --version
> > g++ (GCC) 3.2.2 20030222 (Red Hat Linux 3.2.2-5)
>
> Debian ships a 3.2.3-prerelease in unstable right now. Hmm.

I just updated my "unstable" and tested; it still has the problem.  :(

> I've just stumbled over http://bugs.debian.org/188943 ("g++-3.2: code
> using dynamic_cast causes segfaults when -fno-rtti is used"), but I guess that
> does not apply to use, right?

A google search about -fno-rtti suggested that the compiler should prompt
an error message when it encounters dynamic_cast<>() statements with
-fno-rtti option set. RTTI is required by dynamic_cast<>() statements.

> >        Mandrake-9.0            ok
> >        RedHat 8.0              ok
> >        RedHat 9.0              ok
> >        Debian "testing"        problems
> >        Debian "unstable"       problems
>
> Does RedHat-8 use g++-3.2 already? I'll try to find the RH-9 Changelog
> and see if they perhaps applied some patches to fix this problem.

Yes, the following are version info for RedHat8 and Mandrake9 g++:

$ g++ --version
g++ (GCC) 3.2 20020903 (Red Hat Linux 8.0 3.2-7)
Copyright (C) 2002 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is
NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.

$ g++ --version
g++ (GCC) 3.2 (Mandrake Linux 9.0 3.2-1mdk)
Copyright (C) 2002 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is
NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE.

Both of the above work, so I think the error has existed already some time
in the Debian compilers. I also think that g++-3.0 worked in Debian but I
didn't use it much and I guess I haven't used g++-3.1 at all. Hummm...
I could in fact install and test them. In "testing" it goes this way:

	debian "testing" g++-3.0 : does NOT work; has the same problem
					as g++-3.2!!!

	debian "testing" g++-3.1 : the packages do not exist???

I double-checked it, but it seems to be true that also g++-3.0 has the
dynamic_cast problem. Quite surprising! The bug can be very old then? Or
is there a library or other tool (like a linker or something else that
handles the binary files) that the both compilers use?

Later today I could do an interesting experiment by taking the object
files compiled by a RedHat9 compiler and then I link them using Debian
tools and libs, let's see what happens.

> I did something like that for mopac7 a while (maybe a year) ago. I can
> try to dig that up if you want.

Thanks. Sure I could use it but don't use many minutes looking for it;
I can take the mopac case as an automake-excercise.

Regards,

	Tommi