gentoo-overlay/metadata/news/2015-10-22-gcc-5-new-c++11-abi/2015-10-22-gcc-5-new-c++11-abi.en.txt

Title: GCC 5 Defaults to the New C++11 ABI
Author: Mike Frysinger <vapier@gentoo.org>
Content-Type: text/plain
Posted: 2015-10-22
Revision: 2
News-Item-Format: 1.0
Display-If-Installed: >=sys-devel/gcc-5

GCC 5 uses the new C++ ABI by default.  When building new code, you might run
into link time errors that include lines similar to:
...: undefined reference to '_ZNSt6chrono12steady_clock3nowEv@GLIBCXX_3.4.17'

Or you might see linkage failures with "std::__cxx11::string" in the output.

These are signs that you need to rebuild packages using the new C++ ABI.
You can quickly do so by using revdep-rebuild (from gentoolkit).

For gentoolkit-0.3.1 or higher:
# revdep-rebuild --library 'libstdc++.so.6' -- --exclude gcc

For previous versions of gentoolkit:
# revdep-rebuild --library 'libstdc\+\+\.so\.6' -- --exclude gcc

For more details, feel free to peruse:
https://developerblog.redhat.com/2015/02/05/gcc5-and-the-c11-abi/
https://blogs.gentoo.org/blueness/2015/03/10/the-c11-abi-incompatibility-problem-in-gentoo/