libstdc++ versioning issues about opencv HOT 6 CLOSED

Okay, doing further research into this and learning some things. This is a problem with the new 3.2.0 binaries just released, too, so it's high priority now.

Static linking libc is not the answer, but making sure we link against an old enough version of libc should work since they remain backwards compatible for a long time.

By doing strings libstdc++.so.6 | grep LIBCXX (in /usr/lib/x86_64-linux-gnu on Ubuntu) it's possible to see what versions are supported by the library.

Ubuntu 12.04.5: 3.4 - 3.4.16
Ubuntu 14.04.5: 3.4 - 3.4.19
Ubuntu 16.04.1: 3.4 - 3.4.21
Wheezy (debian 7.11.0): 3.4 - 3.4.17.

The newly built binaries are looking for 3.4.20. I'm not sure why that, rather than 21 since that is the latest supported where they were built.

from opencv.

Note: Travis CI is using Ubuntu 12.04, so the new builds fail there, too.

https://docs.travis-ci.com/user/ci-environment/

https://travis-ci.org/openpnp/openpnp/builds/186893373#L1465

http://stackoverflow.com/questions/10354636/how-do-you-find-what-version-of-libstdc-library-is-installed-on-your-linux-mac

http://unix.stackexchange.com/questions/120380/what-c-library-version-does-my-system-use

https://www.debian.org/releases/wheezy/

http://gcc.gnu.org/onlinedocs/libstdc++/manual/abi.html

http://askubuntu.com/questions/163138/how-do-i-find-what-version-of-libc-my-application-links-to

http://stackoverflow.com/questions/4133674/glibcxx-versions

from opencv.

A trusted advisor suggests supporting back to Ubuntu 14.04 and calling that good.

from opencv.

Summary of learnings so far:

libstdc++ uses symbol versioning. Symbol versions are the 3.4.x stuff and every symbol version will need to be present.
readelf -a libopencv_java320.so | grep GLIBCX gets us the symbol versions in the library. For the 3.2.0-0 release it is showing 11, 15, 9, 20, 21, 4. Since 21 is the highest, I would expect it to fail on any machine where 21 was not available and in our list of versions above that is only Ubuntu 16.04.

So, I don't think there is a way to determine what versions we'll need until we compile OpenCV on a lower version and check it's symbols.

from opencv.

Confirmed on 14.04:
libstdc++.so.6 (GLIBCXX_3.4.11) => /usr/lib/x86_64-linux-gnu/libstdc++.so.6
libstdc++.so.6 (GLIBCXX_3.4.15) => /usr/lib/x86_64-linux-gnu/libstdc++.so.6
libstdc++.so.6 (GLIBCXX_3.4.9) => /usr/lib/x86_64-linux-gnu/libstdc++.so.6
libstdc++.so.6 (GLIBCXX_3.4.20) => not found
libstdc++.so.6 (GLIBCXX_3.4.21) => not found
libstdc++.so.6 (GLIBCXX_3.4) => /usr/lib/x86_64-linux-gnu/libstdc++.so.6

20 and 21 are not found.

from opencv.

3.2.0-1 has been released, which has Linux binaries built on Ubuntu 14.04.5. The resulting binaries require GLIBCXX 3.4.15 which should make it compatible with Ubuntu going back to 12.04 and Debian Wheezy. In particular, the library is now compatible with Ubuntu 14.04 which makes it work on Travis CI builds again.

from opencv.