Confusion over boost::python installation and example/tutorial instructions

[JayAtlis]

Hello,

I'm attempting to install boost::python on a Raspbian bullseye (32 bit) system. First, I followed the instructions at https://www.boost.org/doc/libs/1_81_0/more/getting_started/unix-variants.html to build bjam (b2) and install the boost::python libraries and headers...

jay@raspberrypi:~/boost_1_81_0 $ ./bootstrap.sh --with-libraries=python --prefix=/home/jay/boost_libs
...
jay@raspberrypi:~/boost_1_81_0 $ ./b2 install

It completed without error.

Then, I followed the instructions at https://www.boost.org/doc/libs/1_81_0/libs/python/doc/html/tutorial/tutorial/hello.html to build the example...

jay@raspberrypi:~/boost_1_81_0/libs/python/example/tutorial $ ~/boost_1_81_0/b2
...found 11 targets...
...updating 3 targets...
gcc.link.dll hello_ext.so
/usr/bin/ld: cannot find -lboost_python
collect2: error: ld returned 1 exit status

    "g++"    -o "hello_ext.so" -Wl,-h -Wl,hello_ext.so -shared -Wl,--start-group "hello.o"  -Wl,-Bstatic  -Wl,-Bdynamic -lboost_python -ldl -lpthread -lutil -Wl,--end-group -fPIC -g

...failed gcc.link.dll hello_ext.so...
...skipped <p.>hello for lack of <p.>hello_ext.so...
...failed updating 1 target...
...skipped 2 targets...

It seems that b2 isn't correctly locating the boost_python library. I've also tried installing the boost libraries and headers to the system (/usr/local/) and it made no difference.

I can see the libraries in the filesystem:

jay@raspberrypi:~ $ ls ~/boost_libs/lib/
cmake  libboost_numpy39.a  libboost_numpy39.so  libboost_numpy39.so.1.81.0  libboost_python39.a  libboost_python39.so  libboost_python39.so.1.81.0
jay@raspberrypi:~ $ ls /usr/local/lib/
cmake  libboost_numpy39.a  libboost_numpy39.so  libboost_numpy39.so.1.81.0  libboost_python39.a  libboost_python39.so  libboost_python39.so.1.81.0  python3.9

Please can you help me determine what's missing?

-Thanks,
-Jay

[JayAtlis]

I was able to resolve the issue by creating a new symlink:
$ sudo ln -s /usr/local/lib/libboost_python39.so /usr/local/lib/libboost_python.so

Now I can build, but I suspect this was a hack and didn't address the root problem.

[stefanseefeld]

I agree. This seems to be an issue with Boost.Build. @pdimov , @grafikrobot , any thoughts ?

[grafikrobot]

It's an effect of how the BPL example Jamfiles are written. Specifically they don't have a mechanism for finding, or specifying, the BPL library. The examples default to looking for "boost_python" lib/so/dll (https://github.com/boostorg/python/blob/master/example/Jamroot#L21).