glibcxx-symbol-versioning

Sample code to demonstrate how libstdc++ symbol versioning works

First read about versioned symbols at http://ftp.ntu.edu.tw/software/libs/glibc/hjl/compat/. Then dig into the travis results for this repo to see how specific test programs do or do not end up using specific versioned symbols.

Testing methods:

• Travis jobs
• Using the default libstdc++ packages and ones upgraded from https://launchpad.net/~ubuntu-toolchain-r/+archive/ubuntu/test
• Studying https://github.com/gcc-mirror/gcc/blob/d7b41a73a78cbd6f291bf8d4090638057b964c11/libstdc%2B%2B-v3/config/abi/pre/gnu.ver#L1599-L1602 for when symbols arrived

Findings based on testing:

Default precise

• libc6 2.15-0ubuntu10.10
• libstdc++6 4.6.3-1ubuntu5
• GLIBCXX_3.4.16
• Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.6
• GLIBCXX: 20120301

Default trusty

• libstdc++6 4.8.4-2ubuntu1~14.04.3
• GLIBCXX_3.4.19
• Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
• GLIBCXX: 20150426

Bug with -std=c++14:

/usr/lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/cstdio:120:11: error: 
      no member named 'gets' in the global namespace
  using ::gets;
        ~~^

libstdc++-4.8-dev upgrade on precise (via toolchain-r)

• libstdc++6 6.2.0-3ubuntu11~12.04
• libgcc-4.8-dev amd64 4.8.1-2ubuntu1~12.04
• libstdc++-4.8-dev amd64 4.8.1-2ubuntu1~12.04
• GLIBCXX_3.4.22
• Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
• GLIBCXX: 20130604

libstdc++-4.9-dev upgrade on precise (via toolchain-r)

• libstdc++6 6.2.0-3ubuntu11~12.04
• libgcc-4.9-dev amd64 4.9.4-2ubuntu1~12.04
• libstdc++-4.9-dev amd64 4.9.4-2ubuntu1~12.04
• GLIBCXX_3.4.22
• Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
• GLIBCXX: 20160726
• std::get_new_handler()@@GLIBCXX_3.4.20

libstdc++-5-dev upgrade on precise (via toolchain-r)

• libstdc++6 6.2.0-3ubuntu11~12.04
• libgcc-5-dev amd64 5.4.1-2ubuntu1~12.04
• libstdc++-5-dev amd64 5.4.1-2ubuntu1~12.04
• GLIBCXX_3.4.22
• Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.1
• GLIBCXX: 20160904
• std::out_of_range::out_of_range(char const*)@@GLIBCXX_3.4.21
• std::__codecvt_utf8_utf16_base<wchar_t>::do_encoding() const@@GLIBCXX_3.4.21
• std::runtime_error::runtime_error(char const*)@@GLIBCXX_3.4.21

libstdc++-6-dev upgrade on precise (via toolchain-r)

• libstdc++6 6.2.0-3ubuntu11~12.04
• libgcc-6-dev amd64 6.2.0-3ubuntu11~12.04
• libstdc++-6-dev amd64 6.2.0-3ubuntu11~12.04
• GLIBCXX_3.4.22
• Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.2.0
• GLIBCXX: 20160901
• std::__codecvt_utf8_utf16_base<wchar_t>::do_encoding() const@@GLIBCXX_3.4.21
• std::runtime_error::runtime_error(char const*)@@GLIBCXX_3.4.21

libstdc++ version on all linux distros: https://pkgs.org/download/libstdc++6