target_link_libraries and INCLUDE_DIRECTORIES property

Question

In this snippet:

cmake_minimum_required(VERSION 3.0)
project(hello LANGUAGES C VERSION 0.0.1)
add_library(a INTERFACE)
target_include_directories(a INTERFACE /us         


        

Answer 1

target_link_libraries does not add any directory, it adds the specific library that you've included. Use make VERBOSE=1 to see the complete command. You might be able to get the library output directory by reading the build directory or the library output name.

Answer 2

The problem is that the information you are seeking is only available after the generation step. You can get those only with e.g. add_custom_target() calls, which run during compile time. Your get_target_property() and message() calls run during CMake configuration step.

Disclaimer: Taken with small modifications from the question linked below:

add_custom_command(
    b_lists ALL
    ${CMAKE_COMMAND} -E echo "b INCLUDE_DIRECTORIES: $<TARGET_PROPERTY:B,INCLUDE_DIRECTORIES>"
)

References

• Recursive list of LINK_LIBRARIES in CMake
• target_include_directories prior to 2.8.12?