Le 15/05/2015 20:38, Ken Moffat a écrit : > On Fri, May 15, 2015 at 10:36:36AM -0500, Bruce Dubbs wrote: >> Pierre Labastie wrote: >>> Today is slightly less busy for me and I have some time to study the new >>> gcc 5. >>> as already noted in >>> http://lists.linuxfromscratch.org/pipermail/blfs-dev/2015-April/030081.html, >>> there is an ABI change in the libstdc++ library. The old behavior can be >>> preserved, though, because all the symbols (old and new) are contained in >>> the >>> libstdc++.so shared object. However this is not true of other libraries >>> built >>> using C++. The difference between old and new behavior just amounts to >>> change a >>> #define in the header files. This can be set at build time using the switch >>> "--with-default-libstdcxx-abi" in configure. >>> >>> So: >>> a) if you have built part or all of LFS/BLFS with gcc-4.9.2, and want to >>> update >>> to gcc-5.1.0, you need to use "--with-default-libstdcxx-abi=c++98" in order >>> to >>> preserve the old behavior. Otherwise, newly built packages using C++ will >>> not be >>> able to use old libraries built using C++. >>> b) if you have built from scratch using gcc-5.1.0, you need to use >>> "--with-default-libstdcxx-abi=c++11" (or nothing since it is the default). >>> >>> Now the question is: should I assume hypothesis a) or hypothesis b) for GCC >>> in >>> BLFS? In case a), I would put the flag in the instructions and mention that >>> it >>> can be removed in "command explanations". In case b), I would not put the >>> flag >>> in the instructions and mention it in the "command explanations". Or put in >>> another way: should I assume that an user building BLFS-development builds >>> upon >>> LFS-7.7, or upon LFS-development? Actually, I presently am in the first case >>> (but of course, I can rebuild to be in a second case). >> >> Please assume that LFS was built with gcc-5 (case b). In addition to >> putting the switch in "command explanations", I think a <caution> explaining >> the issue just before configure would help emphasize the issue. >> >> -- Bruce >> > Agreed. Sounds like a good solution. > > ĸen >
Thanks, I'll do that. Pierre -- http://lists.linuxfromscratch.org/listinfo/blfs-dev FAQ: http://www.linuxfromscratch.org/blfs/faq.html Unsubscribe: See the above information page
