Using libboost_python3 from any project fails with an "undefined reference" linking problem, because libboost_python3.so.1.62.0 appears to be built incorrectly against Python 2 includes and uses symbols which are not present in Python 3 C library.

libboost_python.so (Python 2) uses PyClass_Type, which is fine:

nm -D tmp-glibc/work/corei7-64-refkit-linux/boost/1.62.0-r1/sysroot-destdir/usr/lib/libboost_python.so.1.62.0 | grep PyClass_Type
                 U PyClass_Type

However, libboost_python3.so also uses the same symbol, which is not fine:

nm -D tmp-glibc/work/corei7-64-refkit-linux/boost/1.62.0-r1/sysroot-destdir/usr/lib/libboost_python3.so.1.62.0 | grep PyClass_Type
                 U PyClass_Type

Looking at the Python C libraries we can see that the symbol is prsent only in Python 2:

nm -D tmp-glibc/work/corei7-64-refkit-linux/boost/1.62.0-r1/recipe-sysroot/usr/lib/libpython3.5m.so | grep PyClass_Type
nm -D tmp-glibc/work/corei7-64-refkit-linux/boost/1.62.0-r1/recipe-sysroot/usr/lib/libpython2.7.so | grep PyClass_Type
000000000038e420 D PyClass_Type

There's some discussion about the issue here:

http://stackoverflow.com/questions/25188861/libboost-python3-so-1-56-0-undefined-symbol-pyclass-type