Use includes of adjacent subproject in cmake

Question

I develop a project which consisting of several shared libraries and build it with CMake. Each library is built via add_subdirectory().

What is the best way to add all the API headers of the fist library to the CMakeLists.txt of the second?

Answer 1

Encode the include directories in the target itself:

http://www.cmake.org/cmake/help/git-master/manual/cmake-buildsystem.7.html#include-directories-and-usage-requirements

That doc is new, but the target_include_directories command exists since CMake 2.8.11. Use it with the INTERFACE or PUBLIC option.

Answer 2

To make an answer of steveire complete:

for the library which exports API we should write

target_include_directories("target_with_api" INTERFACE "path_to_api_includes")

and for the library which uses this API we write

target_include_directories("api_client_target_name" PRIVATE
             $<TARGET_PROPERTY:"target_with_api",INTERFACE_INCLUDE_DIRECTORIES>)

where $<TARGET_PROPERTY:"target_with_api",INTERFACE_INCLUDE_DIRECTORIES>) returns us target property assigned to the library with API