How can I share C++ code between a UWP and Win32 projects in Visual Studio?

Question

I have some code I would like to share in some kind of library project between Win32 and UWP (Universal Windows) projects, how can I do this?

So far I have tried combinations of static, dynamic and WinRT libraries, each time I try to reference them, either the UWP or Win32 project complain that the project being referenced is not compatible. I have seen others copy references to the same code into multiple Visual Studio projects - but this doesn't seem very nice.

I should add that the code I wish to share between the projects is completely compatible with UWP and Win32 (it's a maths module, no low level Windows calls etc.).

My desired code structure:

- Visual Studio Solution
    - SharedLib (either static or DLL)
        - C++ source (in single place)
    - Win32 app [references SharedLib]
    - UWP App (Universal Windows) [references SharedLib]

Can't you just share the same source code files (linking to the same files from win32 and UWP app)? Otherwise have you seen this: blogs.windows.com/windowsdeveloper/2019/04/30/… (more complex) — Simon Mourier
I'd really prefer for one project to own the source in VS, the approach you mention is what I'm currently doing — James
When targeting (very) different framework such as you do, there's usually incompatibilities with MSVC runtime libs (they are many various flavors now: ucrtbase, etc.) and the way they are themselves linked that make that virtually impossible (and can also cause deployment issues). Otherwise, use the link I shared and create WinRT components that you should be able to use in both UWP and Win32 (and prepare to face other deployment issues: VCRTForwarders, etc.) — Simon Mourier
Yes all good points, posting this question I was hoping someone would show how to use WinRT components properly - I have tried and failed to get one to work in a console app and UWP app. I'll stick with the shared source for now, I think I have just gotten used to CMake which lets you do this kind of thing very cleanly. — James
If you want to use the same c++ source code in your console app and UWP app, you could try to create a c++ dll file, then use DllImport to import the dll file and call the methods of dll. — Faywang - MSFT

Sunius Sunius · Accepted Answer · 2020-08-20T04:28:38

You can create a meta-project that contains shared source files with a .vcxitems extension. This meta-project can be included to both UWP and Win32 projects and will make those files be built using the settings from the project it's included from. Here's an example:

SharedSources.vcxitems:

<?xml version="1.0" encoding="utf-8"?>
<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup Label="Globals">
    <MSBuildAllProjects>$(MSBuildAllProjects);$(MSBuildThisFileFullPath)</MSBuildAllProjects>
    <CodeSharingProject>AC2D0373-EEF5-4C0E-AB12-42BA9DE177B8</CodeSharingProject>
    <ItemsProjectGuid>{A07C892B-28CB-4A5F-839E-BF8F6C023808}</ItemsProjectGuid>
    <HasSharedItems>true</HasSharedItems>
  </PropertyGroup>
  <ItemGroup>
    <ClCompile Include="$(MSBuildThisFileDirectory)MySourceFile.cpp">
    </ClCompile>
    <ClInclude Include="$(MSBuildThisFileDirectory)MySourceFile.h">
    </ClInclude>
  <ItemGroup>
    <ProjectCapability Include="SourceItemsFromImports" />
  </ItemGroup>
</Project>

Then, at the very end of both Win32 and UWP .vcxproj add this:

  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
  <Import Project="SharedSources.vcxitems" Label="SharedSources" />
</Project>

Also, don't forget to add the project to your solution (.sln) file:

Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "Win32Project", "Projects\Win32Project.vcxproj", "{9FFABC4E-F9A7-4438-898A-C7398A21F867}"
EndProject
Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "UWPProject", "Projects\UWPProject.vcxproj", "{7CD23966-75BC-4444-825E-16C3E5F7FB22}"
EndProject
Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "SharedSources", "Projects\SharedSources.vcxitems", "{A07C892B-28CB-4A5F-839E-BF8F6C023808}"
EndProject

How can I share C++ code between a UWP and Win32 projects in Visual Studio?

1 Answers