CMAKE and Visual Studio 2019 - how to add own c-subfunctions - what to add in CMakeLists.txt?

Question

Hi,

I am new to CMake with VS.

I have an old project with several c modules.

When i try to compile the whole thing, everything is fine.

But when I try to add a new module named mytest.c with a function testit.c in it and call it within my main module i get a 2019 error.

And within cmake.setup I get "CMake Error at cmake/setup.cmake:73 (target_sources).

I think i missed something to reference the new module.

But where should it be done?

Thanks in advance.

cua
michael