On Wed, 5 Sep 2007, Glenn Horton-Smith wrote:

> Greetings,
>
>   It seems that SL4's gcc4-c++ package ("GCC version 4.1 preview")
> doesn't install gcc 4.1's include files, but instead g++4 is configured
> to use gcc3.4.3's include files ("g++4 -v" reports the
> "--with-gxx-include-dir=/usr/include/c++/3.4.3" option was used).  This
> causes an enormous quantity of dire warning messages from various
> standard library classes (including <string>) when compiling almost
> anything with -O2 (such as CLHEP2 uses by default).  These warnings are
> all to the effect that "dereferencing type-punned pointer will break
> strict-aliasing rules."
>
>   This almost seems like it might be a mistake, and it is actually a
> problem for me, as my whole reason for trying to compare gcc4 and
> gcc3.4.3 was to try to diagnose a discrepancy we think we're seeing in
> the behavior of a Geant4 simulation compiled with gcc4 on one system vs.
> gcc3.4.3 on another.  In particular, I've become somewhat suspicious of
> the type-punning in CLHEP2 because of a number of gcc bug reports of
> incorrect code being generated by gcc4.1 due to incorrect
> strict-aliasing optimizations.  But with g++4 configured to use a
> standard template library that's not compatible with g++4, I don't see
> there's much point in proceeding with it as is.
>
>   So, my question: is it possible to get gcc4* rpms for SL4 which
> install and use /usr/include/c++/4.1.1?  (Also the corresponding version
> of libstdc++, for that matter.)  If yes, it will save me some work; if
> not, I guess I'll have to install GCC4 from source if I want to make the
> comparison.

Can you tell me the exact g++4 rpm name in question.

rpm -qa | grep g++

I will research this.

-Connie Sieh
>
>             Best regards,
>                            -Glenn Horton-Smith
>