Re: linux build and version symlinks question

From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2020-06-15 16:04:48

On 2020-06-15 17:43, Aleksei Nikiforov via Boost wrote:
> 15.06.2020 17:28, Andrey Semashev via Boost пишет:
>> On 2020-06-15 17:09, Aleksei Nikiforov via Boost wrote:
>>>
>>> Not sure what happens with them in Debian, but those symlinks seem to be
>>> not packaged as well.
>>
>> Debian/Ubuntu packages do have symlinks - in dev packages. Binary
>> packages only contain libraries with ABI version tags in their names.
>>
>> https://packages.debian.org/buster/amd64/libboost-filesystem1.67-dev/filelist
>>
>> https://packages.debian.org/buster/amd64/libboost-filesystem1.67.0/filelist
>>
>> In general, you do want the untagged library names available only in dev
>> packages to enable linking with the library. In binary packages you want
>> tagged library names to allow installing multiple ABI-incompatible
>> versions of the library on target systems. Since Boost does not maintain
>> ABI compatibility, this means Boost libraries include the full Boost
>> version as the ABI tag.
> 
> There are no libboost_filesystem.so.1.67 and libboost_filesystem.so.1
> symlinks in boost 1.67.0.

Why would they be needed?

Such multi-layered symlinks are created in cases when there are 
different guarantees offered by different library names or backward 
compatibility reasons (e.g. the library was renamed or changed its 
tagging scheme at some point). This is not the case with Boost, so 
there's no point in creating or packaging them.

> Let's take a look at boost 1.71.0. In Debian only libboost_filesystem.so
> is packaged into dev package, and libboost_filesystem.so.1.71.0 is
> packaged into library package. libboost_filesystem.so.1.71 and
> libboost_filesystem.so.1 are missing while they should be present after
> boost build:
> 
> https://packages.debian.org/sid/amd64/libboost-filesystem1.71-dev/filelist
> https://packages.debian.org/sid/amd64/libboost-filesystem1.71.0/filelist

What makes you think libboost_filesystem.so.1.71 and 
libboost_filesystem.so.1 should be present?