CMake: How to handle multiple versions of same libraries? - cmake

Question

in my project I am using the header only library rapidjson v1.1.0.
└── my_project
├── CMakeLists.txt
├── src
│
├── 3rdParty/tiny_dnn (header only)
│ ├── CMakeLists.txt
│ ├── src
│ └── rapidjson_v0.2
│
└── rapidjson_v1.1.0
The problem is now that tiny-dnn has also included rapidjson (but an older version), so while i try to include tiny_dnn in the main CMakeLists.txt like include_directories(${PROJECT_SOURCE_DIR}/3rdParty/tiny_dnn) some conflicts arise from either tiny-dnn searches mine rapidjson or my project searches in tiny-dnn's rapidjson.
my_project CMakeLists.txt
cmake_minimum_required(VERSION 3.9)
project(my_project)
# check the build type and set compiler and linker flags
set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
string(TOUPPER ${CMAKE_BUILD_TYPE} CMAKE_BUILD_TYPE)
IF(CMAKE_BUILD_TYPE MATCHES DEBUG)
message("Debug build")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wno-unknown-pragmas -g -O0 -std=c++17 -Ddeveloper_build")
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -fPIC -g -O0")
ELSEIF(CMAKE_BUILD_TYPE MATCHES RELEASE)
message("Release build")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wno-unknown-pragmas -O3 -std=c++17")
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -O3")
ELSE()
message(FATAL_ERROR "No build type specified")
ENDIF()
find_package(Boost COMPONENTS system filesystem REQUIRED)
include_directories(${Boost_INCLUDE_DIRS} ${PROJECT_SOURCE_DIR}/3rdParty/tiny-dnn)
file(GLOB_RECURSE SOURCE_FILES src/*.cpp src/*.c)
set(SOURCE_FILES
${SOURCE_FILES})
add_executable(my_project ${SOURCE_FILES})
target_link_libraries(my_project ${Boost_LIBRARIES} pthread)
set_target_properties(my_project PROPERTIES SUFFIX ${CMAKE_BUILD_TYPE})
my_project.cpp
#include <tiny_dnn/tiny_dnn.h>
#include <rapidjson/rapidjson.h> // <- usr/local/include/rapidjson
int main(int argc, char **argv)
{
rapidjson::Document d; // <- uses rapidjson (v0.2) of tiny_dnn/cereal/external/rapidjson but in my project i would use /usr/local/include/rapidjson (v1.0.1)
return 0;
}

Answer 1

In general - don't. Force one client to use higher / better. Even if you walk around those problems, you are likely to violate one definition rule and get segfault later.