My solution is to use add_subdirectory with relative patch to shared_lib directory. I don't think that this is a perfect solution it has its caveats:
- Logic very similar to a header guard must be added to library CMakeLists.txt to prevent from defining targets multiple times.
- Each CMakeList.txt file must know the relative path to the library, if one want to move library all CMakeLists must be updated.
Let's assume that the directory structure looks like this:
root/
CMakeLists.txt
shared_lib/
CMakeLists.txt
inc/
foo.h
src/
foo.c
exec1/
CMakeLists.txt
main.c
exec2/
CMakeLists.txt
main.c
root/CMakeList.txt
cmake_minimum_required(VERSION 2.6)
add_subdirectory(shared_lib)
add_subdirectory(exec1)
add_subdirectory(exec2)
I have decided that shared_lib/CMakeLists.txt will export a variable named SHARED_DIR_INCLUDE_DIR
. This approach helps to decouple things a little bit.
root/exec1/CMakeLists.txt
cmake_minimum_required(VERSION 2.6)
add_subdirectory(./../shared_lib shared_lib)
include_directories(${SHARED_LIB_INCLUDE_DIR})
set(SRCS main.c)
add_executable(exec1 ${SRCS})
target_link_libraries(exec1 shared_lib)
if()
in the fourth line solves the issue with target's multiple definition in case the CMakeLists file is added multiple times. The second and the third lines exports the include directory for library in SHARED_LIB_INCLUDE_DIR
root/shared_lib/CMakeLists.txt
cmake_minimum_required(VERSION 2.6)
set(SHARED_LIB_INCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/inc)
set(SHARED_LIB_INCLUDE_DIR ${SHARED_LIB_INCLUDE_DIR} PARENT_SCOPE)
if(TARGET shared_lib)
message("shared_lib is already defined")
else()
include_directories(${SHARED_LIB_INCLUDE_DIR})
set(LIB_SRCS ./src/foo.c)
add_library(shared_lib STATIC ${LIB_SRCS})
endif()