25.11.2016, 03:38, "Kevin Kofler" <kevin.kof...@chello.at>: > Lars Knoll wrote: >> There are a lot of good arguments towards using the STL and libstdc++ >> more, as it will allow us to interoperate better with the C++ standard, >> and provides a couple of things that we really want to use. So I can see >> many good arguments towards going down that route. Doing so will bind the >> compiled Qt binary to a certain version of that library (ie, it will >> require a recompile of Qt to switch from libc++ to libstdc++). To a large >> extent that is no different than the situation we're facing with e.g. >> different VC++ runtimes. It also doesn't create impossible challenges for >> the Linux packagers/distributors (or at least the challenges won't be >> caused by us). So I'm positive towards using more of the standard >> functionality and APIs (and also exposing them in our APIs). > > libstdc++ now has a sub-ABI-version that was already bumped recently for > better C++11 compliance. It can be bumped again, without even changing the > soname, and all libraries using the std:: types in their APIs will have a > broken ABI. > > That would leave us distributors only with very unpleasant solutions: > (a) rebuild everything using Qt in reverse dependency order, which has to be > computed first. Alphabetic order, as normally used by the Fedora mass > rebuild scripts, will almost certainly not work, due to symbol lookup > failures.
Gentoo provides revdep-rebuild for ages. Looks like you guys are stuck with crappy tooling. > (b) pin libstc++ to an old version forever. > (c) patch libstdc++ to stick to the old ABI forever. > (d) tweak the build flags of Qt, everything using Qt, all C++ libraries it > uses, everything using those libraries, etc., propagating back and > forth, to stick to the old ABI forever. That is likely all or almost all > C++ stuff in the distribution. So (d) is probably just a very > complicated way to implement (c). > (e) hack things up so that Qt uses the old ABI types for its own APIs > (forever), but the new ABI types for libraries it uses that have already > been rebuilt. That requires patching Qt with libstdc++-specific hacks > and maintaining those patches forever. > > Neither of those is really acceptable. > > Kevin Kofler > > _______________________________________________ > Development mailing list > Development@qt-project.org > http://lists.qt-project.org/mailman/listinfo/development -- Regards, Konstantin _______________________________________________ Development mailing list Development@qt-project.org http://lists.qt-project.org/mailman/listinfo/development
