On 24 March 2016 at 11:55, Jeffrey Walton wrote: > In the test program below, why does -Wabi-tag trigger a warning with > the std::string when using -std=c++03? "Although the changes were made for C++11 conformance, the choice of ABI to use is independent of the -std option used to compile your code, i.e. for a given GCC build the default value of the _GLIBCXX_USE_CXX11_ABI macro is the same for all dialects. This ensures that the -std does not change the ABI, so that it is straightforward to link C++03 and C++11 code together. " https://gcc.gnu.org/onlinedocs/libstdc++/manual/using_dual_abi.html