Using swig_add_library in cmake

CMakeLists.txt

cmake_minimum_required(VERSION 3.21)
project(codebase_wrapper LANGUAGES CXX)

find_package(SWIG REQUIRED)
include(${SWIG_USE_FILE})

include_directories(${CMAKE_SOURCE_DIR})
set(SOURCES codebase_wrapper.i codebase.c)

set_property(SOURCE codebase_wrapper.i PROPERTY CPLUSPLUS ON)

swig_add_library(${PROJECT_NAME}
 TYPE SHARED
 LANGUAGE csharp
 OUTPUT_DIR "${CMAKE_CURRENT_BINARY_DIR}/Generated"
 OUTFILE_DIR "${CMAKE_CURRENT_BINARY_DIR}/Wrapper"
 SOURCES ${SOURCES}
)

codebase.c

#include "codebase.h"
#include <stdlib.h>
#include <string.h>

__declspec(dllexport) void helloWorld()
{
}

codebase.h

// codebase.h
#ifndef CODEBASE_H
#define CODEBASE_H

__declspec(dllexport) typedef struct {
    int id;
} DataStruct;

__declspec(dllexport) void helloWorld();

#endif // CODEBASE_H

codebase_wrapper.i

%module codebase_wrapper
%{
#include "codebase.h"
%}

%include <windows.i>

%include "codebase.h"

Software Details

• cmake version 3.31.6
• Microsoft Visual Studio 2022 Community
• Windows 11

Running this example

C:\Users\Stanley\Documents\CMakeHelp> cmake -B build -S . -A x64
-- Building for: Visual Studio 17 2022
-- Selecting Windows SDK version 10.0.22621.0 to target Windows 10.0.26100.
-- The CXX compiler identification is MSVC 19.43.34809.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: C:/Program Files/Microsoft Visual Studio/2022/Community/VC/Tools/MSVC/14.43.34808/bin/Hostx64/x64/cl.exe - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Found SWIG: C:/Users/Stanley/AppData/Local/Microsoft/WinGet/Packages/SWIG.SWIG_Microsoft.Winget.Source_8wekyb3d8bbwe/swigwin-4.2.1/swig.exe (found version "4.2.1")
-- Configuring done (1.1s)
-- Generating done (0.0s)
-- Build files have been written to: C:/Users/Stanley/Documents/CMakeHelp/build
C:\Users\Stanley\Documents\GitHub\CMakeHelp> cmake --build build --config Release
MSBuild version 17.13.19+0d9f5a35a for .NET Framework

  1>Checking Build System
  Swig compile codebase_wrapper.i for csharp
  Building Custom Rule C:/Users/Stanley/Documents/CMakeHelp/CMakeLists.txt
  codebase_wrapperCSHARP_wrap.cxx
     Creating library C:/Users/Stanley/Documents/CMakeHelp/build/Release/codebase_wrapper.lib and object C:/Users/S
  tanley/Documents/CMakeHelp/build/Release/codebase_wrapper.exp
codebase_wrapperCSHARP_wrap.obj : error LNK2019: unresolved external symbol "void __cdecl helloWorld(void)" (?helloWorld@@YA
XXZ) referenced in function CSharp_helloWorld [C:\Users\Stanley\Documents\CMakeHelp\build\codebase_wrapper.vcxproj] 
C:\Users\Stanley\Documents\CMakeHelp\build\Release\codebase_wrapper.dll : fatal error LNK1120: 1 unresolved externa 
ls [C:\Users\Stanley\Documents\CMakeHelp\build\codebase_wrapper.vcxproj]

Problem in build\codebase_wrapper.vcxproj

codebase.c is included in codebase_wrapper.vcxproj as None. Everything works if I were to manually change it to CLCompile.

<Project>
...
  <ItemGroup>
    <ClCompile Include="C:\Users\Stanley\Documents\CMakeHelp\build\Wrapper\codebase_wrapperCSHARP_wrap.cxx" />
    <None Include="C:\Users\Stanley\Documents\CMakeHelp\build\Generated\codebase_wrapper.cs">
    </None>
    <None Include="C:\Users\Stanley\Documents\CMakeHelp\build\Generated\codebase_wrapperPINVOKE.cs">
    </None>
    <None Include="C:\Users\Stanley\Documents\CMakeHelp\codebase.c">
    </None>
  </ItemGroup>
...
</Project>

Asked in: https://discourse.cmake.org/t/adding-cxx-sources-to-swig-add-library/13838