I have a source layout like this:

project
  |------ CMakeLists.txt (The TOP Cmake)
  |------ Exe_C (For cortexM3)
  |          |----- CMakeList.txt
  |          |----- src
  |          |        cortex_main.c
  |          |----- include
  |          |         various.h files
  |------ Exe_R (For RiscV)
  |          |----- CMakeList.txt
  |          |----- src
  |          |        riscv_main.c
  |          |----- include
  |          |         various.h files
  | 
  |------ hardware_drivers
  |        |----- CMakeList.txt
  |        |----- include/driver
  |        |         Generic .H driver files
  |        |----- src_generic
  |        |         generic driver src
  |        |----- src_cortexM 
  |        |         cortexM3 only src
  |        |----- src_riscV
  |        |         riscv only src
  | ---- app_common
  |        |----- CMakeList.txt
  |        |----- src 
  |        |        common source files
  |        |        for all exes
  |        |----- include
  |        |        common include files
  |        |        for all exes
  |----- feature_FOO (also a Feature BAR)
  |        |----- CMakeList.txt
  |        |---- src
  |        |       src files for FOO
  |        |---- include
  |        |       src files for FOO

So the top level CMAKE file takes a command line -D EXE=EXE_C or -D EXE=EXE_C, then includes() not add_directory() a ${EXE_NAME}-config.cmake file that is unique to the specific app.

The intent is that ${EXE_NAME}-config.cmake knows what Drivers it needs, it knows what CPU it requires, and what DRIVER files it wants and what Features (FOO or BAR) that it should have.

By cmake-requirement, the TOP LEVEL Cmakefile must define a PROJECT().

The ${EXE_NAME}-config.cmake does an add_executable()

And the other CMake files are trying to add SOURCES to the executable but I cannot.

when I do, it says: Cannot specify sources for target “NAME” which is not built by this project. This fails for multiple directories…

Question# 1 is my structure ok? Or insane?

Question #2 – how can I print {for debug reason} the TARGET that it thinks it wants to build so that I can debug this? (I’ve spent several days and keep hitting the same problem/wall and it is painful}