Share files between multiple groups under CMake - c++

Question

I`m trying to create a CMake setup for a project with the following structure:
workshop
| CMakeLists.txt
| utilities
| | utilities.h
| | utilities.cpp
| | CMakeLists.txt
| week_1
| | week_1.h
| | week_1.cpp
| | main.cpp
| | CMakeLists.txt
| week_2
| | main.h
| | week_2.cpp
| | main.cpp
| | CMakeLists.txt
Everything depends on OpenCV and the programs in week_X depend also on utilities.
I was able to do everything except the connection with utilities.
My trial:
File workshop\CMakeLists.txt
cmake_minimum_required(VERSION 2.8.12)
PROJECT(workshop)
SET(OpenCV_DIR OPENCV_DIR)
find_package( OpenCV REQUIRED )
include_directories( ${OpenCV_INCLUDE_DIRS})
add_subdirectory(${CMAKE_SOURCE_DIR}/utilities)
add_subdirectory(${CMAKE_SOURCE_DIR}/week_1)
add_subdirectory(${CMAKE_SOURCE_DIR}/week_2)
File week_1\CMakeLists.txt (week_2\CMakeLists.txt is identical just changing 1 by 2)
cmake_minimum_required(VERSION 2.8.12)
include_directories( ${OpenCV_INCLUDE_DIRS})
set(SRCFILES week_1.cpp week_1.h main.cpp)
source_group(week_1 FILES ${SRCFILES})
add_executable(week_1 ${SRCFILES})
target_link_libraries(week_1 ${OpenCV_LIBS})
All is okay until the utilities. How would be the utilities\CMakeLists.txt?

Answer 1

I think you want utilities to be a library.
In the utilities CMakeLists.txt
# This will create libutilities.a
add_library(utilities
utilities.cpp
)
target_include_directories( utilities PUBLIC
${CMAKE_CURRENT_SOURCE_DIR}
# Third party libs
${OpenCV_INCLUDE_DIRS}
)
target_link_libraries(utilities
${OpenCV_LIBRARIES}
)
In week_X you'll use it as a library like so:
include_directories(
${OpenCV_INCLUDE_DIRS}
${CMAKE_SOURCE_DIR}/utilities # Include utilities header
)
set(SRCFILES week_1.cpp week_1.h main.cpp)
source_group(week_1 FILES ${SRCFILES})
add_executable(week_1 ${SRCFILES})
target_link_libraries(
${OpenCV_LIBS}
utilities # Link to libutilites.a
)