How do I correctly create dependencies between targets in CMake?

Question

I am trying to use CMake to set up some simple dependencies between a C++ project and the libraries that it uses.

The set up is as follows

• Project

Answer 1

It is not exactly clear what you want to do, and why Project and Dependency have to be build separately.

My first though on your example would be

1. In PROJECT's CMakeLists.txt:

   • Remove add_dependencies(Project Dependency) There is no need to specify dependency, target_link_libraries() already does that.

2. In DEPENDENCY's CMakeLists.txt:

   • Remove project(Dependency) It builds a library, so why to have own project?
   • Remove target_link_libraries(Dependency) Because it does nothing

Answer 2

Since CMake 2.8.11 you can use target_include_directories. Just simply add in your DEPENDENCY project this function and fill in include directories you want to see in the main project. CMake will care the rest.

PROJECT, CMakeLists.txt:

cmake_minimum_required (VERSION 2.8.11)
project (Project)
include_directories (Project)
add_subdirectory (Dependency)
add_executable (Project main.cpp)
target_link_libraries (Project Dependency)

DEPENDENCY, CMakeLists.txt

project (Dependency)
add_library (Dependency SomethingToCompile.cpp)
target_include_directories (Dependency PUBLIC include)