In one word: anything that relies on std::string might break. The problem is that, prior to g++ 5.x, libstdc++ used a reference counting std::string which conformed to C++98 and C++03 but not C++11. As reference counting was no longer allowed, libstdc++ maintainers tried to be up-to-date with the new standard, and there went g++ 4.7 and g++ 4.7.1. However, upgrade of std::string broke so many libraries, which the community complained about so much that libstdc++ maintainers decided to keep backward compatibility with legacy libraries for some time,and there went g++ 4.7.2, 4.8.x and 4.9.x. But sooner or later they would get rid of it. The result was g++ 5.x.
------------------ Best regards, lh_mouse 2015-07-28 ------------------------------------------------------------- 发件人：Adrian Pop <[email protected]> 发送日期：2015-07-28 08:26 收件人：Msys2,fkafka 抄送： 主题：[Msys2-users] gcc 5.2.0 issues? Hi all, After I upgraded to gcc 5.2.0 I get some weird linking errors. Is it possible that the gcc 5.2.0 generates code that is not linker compatible with libraries built with gcc 4.9.2? To reproduce do this: # install OSG $ pacman -S mingw64/mingw-w64-x86_64-OpenSceneGraph # get an OSG example from http://trac.openscenegraph.org/projects/osg//wiki/Support/UserGuides/Examples $ wget http://trac.openscenegraph.org/projects/osg/export/15027/OpenSceneGraph/trunk/examples/osganimate/osganimate.cpp # compile the example using latest gcc 5.2.0 $ g++ osganimate.cpp `pkg-config --libs openscenegraph` F:\msys\tmp\cch9wEYJ.o:osganimate.cpp:(.text+0x149e): undefined reference to `__imp__ZN3osg14ArgumentParser4readERKNSt7__cxx1112basic_ stringIcSt11char_traitsIcESaIcEEE' F:\msys\tmp\cch9wEYJ.o:osganimate.cpp:(.text+0x151e): undefined reference to `__imp__ZN3osg14ArgumentParser4readERKNSt7__cxx1112basic_ stringIcSt11char_traitsIcESaIcEEE' F:\msys\tmp\cch9wEYJ.o:osganimate.cpp:(.text+0x15b8): undefined reference to `__imp__ZN3osg14ArgumentParser4readERKNSt7__cxx1112basic_ stringIcSt11char_traitsIcESaIcEEE' collect2.exe: error: ld returned 1 exit status Additional question: is it possible to downgrade to gcc 4.9.2 toolchain using pacman? Cheers, Adrian Pop/ ------------------------------------------------------------------------------ _______________________________________________ Msys2-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/msys2-users ------------------------------------------------------------------------------ _______________________________________________ Msys2-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/msys2-users
