Re: Boost cannot find numpy37 on Dockerized Ubuntu 20.04

From: Nathan Ernst (nathan.ernst_at_[hidden])
Date: 2021-02-19 21:04:16

The missing symbols you quoted come from python itself. It looks like
you're missing a "-lpython" linker flag.

Regards,
Nathan

On Fri, Feb 19, 2021, 4:47 AM Roy de Bokx via Boost-users <
boost-users_at_[hidden]> wrote:

>
>
> Op wo 17 feb. 2021 om 20:30 schreef Anonymous Maarten <
> anonymous.maarten_at_[hidden]>:
>
>> Thanks for your answer Maarten!
>>> Please bare with me as I'm a little new to this. Is there some way I can
>>> change the interpreter that is used for installing boost? Or do you think
>>> that adapting the --prefix flag may also work?
>>>
>>
>> When using the pre-built boost packages of a linux distribution (ubuntu),
>> you're generally stuck with the versions/options that its packagers have
>> chosen.
>> A distribution freezes versions to make a more robust experience.
>>
>> Adding a `--prefix` will not help because, first of all, it's not a valid
>> gcc option, and second, ubuntu 18.04 does not provide a
>> libboost-python-py37 shared/static library.
>> Do you really need python 3.7? Doesn't 3.6 suffice?
>>
>
> Thanks! This helped me understanding the issue a bit further. I think 3.6
> should suffice indeed, so I tried using 3.6 by removing the 3.7
> installation from the Dockerfile and using the -lboost_numpy3 flag instead.
> It seems I ran into some linking issue after this. It was able to find the
> right numpy3.so and libboost_python3-py36.so, but I'm getting a lot of
> errors like these:
>
> //usr/lib/x86_64-linux-gnu/libboost_numpy3.so: undefined reference to
> `PyExc_ValueError'
>
> //usr/lib/x86_64-linux-gnu/libboost_python3-py36.so.1.65.1: undefined
> reference to `PyLong_AsLong'
>
> //usr/lib/x86_64-linux-gnu/libboost_python3-py36.so.1.65.1: undefined
> reference to `PyNumber_InPlaceFloorDivide'
>
> //usr/lib/x86_64-linux-gnu/libboost_python3-py36.so.1.65.1: undefined
> reference to `PyBool_Type'
> etc...
>
> I've pasted the full docker file and logs in
> https://github.com/boostorg/boost/issues/462
> Thanks again for any help.
>
>>
>> If you really want to use Boost.Python + python 3.7, you can do 2 things:
>> - stay on ubuntu bionic and build boost yourself (or use an alternative
>> c/c++ package manager, e.g. [conan](https://conan.io/) has a [boost
>> package](https://conan.io/center/boost))
>> - more to a more recent ubuntu release. e.g. ubuntu 20.10 has python 3.8:
>> https://packages.ubuntu.com/groovy/amd64/libboost-python1.71-dev/filelist
>>
> I've also given 20.10 a try, however I ran into the same linking issues as
> mentioned above.
>
>>
>>
>>
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