cmake_minimum_required(VERSION 3.8) project(DummyImport CXX) set(JSON_BuildTests OFF CACHE INTERNAL "") add_subdirectory(${nlohmann_json_source} ${CMAKE_CURRENT_BINARY_DIR}/nlohmann_json) add_executable(with_namespace_target main.cpp) target_link_libraries(with_namespace_target nlohmann_json::nlohmann_json) add_executable(without_namespace_target main.cpp) target_link_libraries(without_namespace_target nlohmann_json)