How to manage the GCC >= 5 ABI

In the GCC 5.1 release libstdc++ introduced a new library ABI that includes new implementations of std::string and std::list. These changes were necessary to conform to the 2011 C++ standard which forbids Copy-On-Write strings and requires lists to keep track of their size.

You can choose which ABI to use in your Conan packages by adjusting the compiler.libcxx:

  • libstdc++: Old ABI.

  • libstdc++11: New ABI.

When Conan create the default profile the first time it runs, adjust the compiler.libcxx setting to libstdc++ for backwards compatibility. If you are using GCC >= 5, your compiler is likely using the new CXX11 ABI by default (libstdc++11).

If you want Conan to use the new ABI, edit the default profile at ~/.conan/profiles/default adjusting compiler.libcxx=libstdc++11 or override this setting in the profile you are using.

If you are using the CMake build helper or the AutotoolsBuildEnvironment build helper Conan will adjust automatically the _GLIBCXX_USE_CXX11_ABI flag to manage the ABI.