On Wed, 5 Sep 2007, Connie Sieh wrote:

> 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++

rpm -qa | grep gcc4-c++

-Connie Sieh

>
> I will research this.
>
> -Connie Sieh
>>
>>             Best regards,
>>                            -Glenn Horton-Smith
>>
>