LNK2005 error of boost::archive::codecvt_null<wchar_t>

[Mitsuhiko-Matsukawa]

When I use boost/archive/xml_wiarchive.hpp in dll and exe together, LNK2005 error occurs.
boost 1_76_0, Visual Studio 2019

LNK2005_codecvt_null.zip

Please download and put as below.
boost_1_76_0
-boost
-stage
--x64
--x86
LNK2005_codecvt_null
-LNK2005_codecvt_null.sln

[Mitsuhiko-Matsukawa]

@robertramey
If I revert these files before Jun 19, 2020, my test code works.

• serialization/include/boost/archive/codecvt_null.hpp
• serialization/src/codecvt_null.cpp

[Mitsuhiko-Matsukawa]

@robertramey
If I revert commit 812ef99 from master branch, my test code works.

[AdmiralPellaeon]

@Mitsuhiko-Matsukawa I have the same issues. I tried your workaround for boost 1.78.0, but this leads to a different linker error. Did you already test it with the newest boost version?
Atm I try to use boost with shared linking to overcome with this problem. But I would prefer to link it statically how I did it all the time before.

[robertramey]

what is the current status on this? I've tested extensively with both static and shared linking with no problems.

[Mitsuhiko-Matsukawa]

@robertramey @AdmiralPellaeon
This issue still exists on boost1.80.0 + Visual Studio 2019.

I have applied this patch and the problem has been resolved.
#240

The idea of this patch is simple.
Move implementations from cpp to hpp so that they will be inline and linker error doesn't occur.

@robertramey
Why did you move them from hpp to cpp? Is there a good point to do that?

[robertramey]

I'm still trying to understand what's going on here. When you "move" this implementation, do you rebuild the libraries when you verify that "it works".

[Mitsuhiko-Matsukawa]

@robertramey
Have you downloaded this file and tried to build?

When you "move" this implementation, do you rebuild the libraries when you verify that "it works".

Yes, I have rebuilt the libraries and succeeded to link to my test code.
My test code fails to link before I move but succeeds after I move.
I have tested only for Visual Studio 2019. It might be error for other platforms. In that case, we should switch by preprocessor.
This issue still exists on 1.81.0.

[oicchris]

Hi! I ran into the same link error and saw this open issue. I just wanted to comment, adding the boost_serialization-vc140-mt.lib to my build fixed the link error. Library was provided by vcpkg, boost v1.81.0 shared library. I hope that solves your issue as well!