How to add library with only module interface unit in msvc?

Usage
1

Show case:

// test.ixx
export module foo;
// No member is declared with dllexport, this is the simplest case.

// test.cpp
import foo;
int main() {}

CMakeLists.txt:

cmake_minimum_required(VERSION 4.1)

project(test)

set(BUILD_SHARED_LIBS ON)
set(CMAKE_CXX_STANDARD 23)

add_library(test)
add_executable(t
    test.cpp
)
target_sources(test
    INTERFACE
        FILE_SET CXX_MODULES
        FILES
            test.ixx
)
target_link_libraries(t
    PRIVATE
        test
)

Apparently there is no test.lib generated because target test doesn’t export any symbol, and result in “LNK1104 cannot open file Debug\test.lib”. As a workaround I must set CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS to ON.
In header files time, I can add it as an interface library, but interface library doesn’t support modules…
So what is the solution for this problem? Thanks!

2

It kinda looks like what you want is an INTERFACE library…

3

Yeah, unfortunately interface library doesn’t support module.:cry: