CMake append objects from different CMakeLists.txt into one library

Question

I would like to create a single library from objects from multiple sub-directories, each one containing their own CMakeLists.txt with OBJECT library trick to have multiple t

Answer 1

I just collect objects from all places using set with PARENT_SCOPE.

root CMakeLists.txt:

set(OBJECTS)

add_subdirectory(lib1)
add_subdirectory(lib2)

add_library(lib STATIC ${OBJECTS})

CMakeLists.txt in subdirectories:

add_subdirectory(lib11)

add_library(${PROJECT_NAME} OBJECT src1.c)
list(APPEND OBJECTS $)
set(OBJECTS ${OBJECTS} PARENT_SCOPE)