Re: [release] Boost 1.84.0 Beta 1 Release Candidate 1 is available

From: Matthijs Möhlmann (matthijs_at_[hidden])
Date: 2023-11-16 17:28:28

On 16/11/2023 17:25, Andrey Semashev via Boost wrote:
> On 11/16/23 19:02, Matthijs Möhlmann via Boost wrote:
>> On 16/11/2023 16:50, Andrey Semashev via Boost wrote:
>>> On 11/16/23 18:43, Matthijs Möhlmann via Boost wrote:
>>>> On 16/11/2023 16:32, Andrey Semashev via Boost wrote:
>>>>> On 11/16/23 18:28, Andrey Semashev wrote:
>>>>>> As for a workaround, I suspect the problem can be worked around by
>>>>>> manually adding linking with the standard library that defines those
>>>>>> missing symbols. For example, `operator delete` is defined in
>>>>>> libc++abi,
>>>>>> so you may fix the problem by adding `linkflags=c++abi` to `b2`
>>>>>> command
>>>>>> line.
>>>>> Sorry, the command line option should be `linkflags=-lc++abi`.
>>>>>
>>>> That didn't work either. Same error.
>>> Do you mean the error still lists `operator delete` and similar core
>>> language symbols as unresolved?
>>>
>>> If so then either the compiler is terminally broken, or there must be
>>> some issue with your installation. Perhaps, inconsistent libc++abi
>>> version?
>>>
>>> BTW, we do test clang-16 in CI, and it passes:
>>>
>>> https://github.com/boostorg/filesystem/actions/runs/6449121898
>>>
>>> so I'm leaning towards some installation or configuration issue.
>> Gotcha, when adding the flags as follows: linkflags="-lc++ -ldc++abi" it
>> works
>> correctly and I have every library build on my system.
> I'm assuming, you meant "-lc++abi" (note the missing "d").
>
>
Yes, I did it with "-lc++abi"

>> Then I guess it has to do with my library path. I have clang installed
>> from the
>> debian repository here:https://apt.llvm.org/
> Yes, but note that there are different repositories for different Debian
> and Ubuntu versions, and also for different clang major releases. When
> you use those repositories, make sure you specify the correct versions
> in the repository line, and also specify the version in the package
> names. For example, for clang-16 you need to install clang-16,
> libc++-16-dev and libc++abi-16-dev - all come from apt.llvm.org.
>
>> I have an user-config.jam in the root of my home directory and it is as
>> follows:
>> import toolset : using ;
>> using clang : 16 : clang-16 ;
>>
>> option jobs : 8 ;
> Our user-config.jam should look like this:
>
> using clang : : clang++-16 ;

Damn, this fixed the issue. Definitely user error then (me) :-(

> See here for how it's composed:
>
> https://github.com/boostorg/filesystem/blob/53eabaeabbf85fda2915a03612323df77fbaf23d/.github/workflows/ci.yml#L455-L460
>
> Note that the compiler executable is clang++-16, not clang-16. The
> former is a C++ compiler, the latter is C. Presumably, the C compiler
> doesn't add C++ standard libraries to the linker. But I would also
> expect it to fail to compile C++ code, or at least display some warning,
> but maybe it doesn't.
>
> Try changing to clang++-16 and compile without explicit `-lc++ -lc++abi`
> flags.
>
>> Maybe that interferes somehow with the ability to link to the correct
>> library?
>>
>> I am not sure where to look further to have this resolved.
> One last thing I'd like to note is that those `-lc++ -lc++abi` flags, if
> you specify those, should come last in the linker command line, and in
> that order. If you have multiple linker flags specified in the command
> line, make sure these two come after any other libraries or object files.

Thanks for the help!

Regards, Matthijs