GCC 5.1 comes after one year of development and it introduces full C++14 language support for the C++ front-end, as well as initial C++14 support and complete C++11 support for the Standard C++ Library, which is possible by adopting Dual ABI. Additionally, GCC 5.1 defaults to the C11 mode with GNU extensions for the C front-end, which brings various user-visible changes, as well as modifications to a semantics of the inline keyword.