How to add subdir sources in target?

Question

I have

dir
    CMakeLists.txt
    main.c
    subdir
        CMakeLists.txt
        file1.c
        file2.c

I am trying to build a target like so

dir CMakeLists.txt has

add_subdirectory(subdir)
add_executable(main main.c ${EXTRA_SOURCES})

subdir CMakeLists.txt has

set(EXTRA_SOURCES file1.c file2.c)

I get a linking error for file1.c and file2.c. They are not being compiled into main binary. I have tried switching

adding_executable(main main.c ${EXTRA_SOURCES})
add_subdirectory(subdir)

I still get linking errors. The compiler will give undefined reference to ... because file1.c and file2.c were not added to main.c objects.

How do I properly set cmake to compile files in the sub directory to the main executable in the main directory?

Normally, variables defined in the subdirectory are not visible in the main directory. Use `PARENT_SCOPE` option for propagate them. See also other answers to the [duplicate question](https://stackoverflow.com/questions/8934295/add-source-in-a-subdirectory-to-a-cmake-project). — Tsyvarev, Jul 19 '20 at 12:25
@Tsyvarev thanks I had been trying to use add_sources which wasnt working. I now realise its important to also declare PRIVATE and PUBLIC — On Demand, Jul 19 '20 at 12:55

0 Answers0