cmake Hierarchical project Simple approach without packages

Example

Example that builds an executable (editor) and links a library (highlight) to it. Project structure is straightforward, it needs a master CMakeLists and a directory for each subproject:

CMakeLists.txt
editor/
    CMakeLists.txt
    src/
        editor.cpp
highlight/
    CMakeLists.txt
    include/
        highlight.h
    src/
        highlight.cpp

The master CMakeLists.txt contains global definitions and add_subdirectory call for each subproject:

cmake_minimum_required(VERSION 3.0)
project(Example)

add_subdirectory(highlight)
add_subdirectory(editor)

CMakeLists.txt for the library assigns sources and include directories to it. By using target_include_directories() instead of include_directories() the include dirs will be propagated to library users:

cmake_minimum_required(VERSION 3.0)
project(highlight)

add_library(${PROJECT_NAME} src/highlight.cpp)
target_include_directories(${PROJECT_NAME} PUBLIC include)

CMakeLists.txt for the application assigns sources and links the highlight library. Paths to hightlighter's binary and includes are handled automaticaly by cmake:

cmake_minimum_required(VERSION 3.0)
project(editor)

add_executable(${PROJECT_NAME} src/editor.cpp)
target_link_libraries(${PROJECT_NAME} PUBLIC highlight)