Problem
The target_include_directories() command has enhanced functionality compared to include_directories() . So I agree with @ Tsyvarev that it mostly depends on how you use target_include_directories() .
Decision
If you use target_include_directories(my_target PRIVATE ...) , the equivalent will be set_property(TARGET my_target APPEND PROPERTY INCLUDE_DIRECTORIES ...) . But include_directories() , by contrast, sets these directories for all purposes in the current CMakeLists.txt and all of them add_subdirectory() siblings.
If you use target_include_directories(my_target INTERFACE/PUBLIC ...) , there is no such function in CMake before version 2.8.11. You can model the behavior of self-propagating include directories, but this is much more complicated.
Recommendation
Do not use the new command if you still want to support older versions of CMake. Because it is not just target_include_directories() (see Matrix / CMake Version Compatibility Commands ).
References
Backward compatibility target_include_directories()
The following code shows what older versions of CMake would have to do to simulate target_include_directories() :
function(target_include_directories _target) set_property(GLOBAL APPEND PROPERTY GLOBAL_TARGETS "${_target}") set(_mode "PRIVATE") foreach(_arg ${ARGN}) if (_arg MATCHES "SYSTEM|BEFORE") message(FATAL_ERROR "target_include_directories: SYSTEM or BEFORE not supported") endif() if (_arg MATCHES "INTERFACE|PUBLIC|PRIVATE") set(_mode "${_arg}") else() get_filename_component(_inc_dir "${_arg}" ABSOLUTE) if (_mode MATCHES "PUBLIC|PRIVATE") set_property(TARGET ${_target} APPEND PROPERTY INCLUDE_DIRECTORIES "${_inc_dir}") endif() if (_mode MATCHES "INTERFACE|PUBLIC") set_property(TARGET ${_target} APPEND PROPERTY MY_INTERFACE_INCLUDE_DIRECTORIES "${_inc_dir}") endif() endif() endforeach() endfunction(target_include_directories) function(target_link_libraries _target) set_property(GLOBAL APPEND PROPERTY GLOBAL_TARGETS "${_target}") set(_mode "PUBLIC") foreach(_arg ${ARGN}) if (_arg MATCHES "INTERFACE|PUBLIC|PRIVATE|LINK_PRIVATE|LINK_PUBLIC|LINK_INTERFACE_LIBRARIES") set(_mode "${_arg}") else() if (NOT _arg MATCHES "debug|optimized|general") set_property(TARGET ${_target} APPEND PROPERTY MY_LINK_LIBARIES "${_arg}") endif() endif() endforeach() _target_link_libraries(${_target} ${ARGN}) endfunction(target_link_libraries) function(my_update_depending_inc_dirs _targets _target _dep_target) get_property(_libs TARGET ${_dep_target} PROPERTY MY_LINK_LIBARIES) if (NOT _libs) return() endif() foreach(_lib ${_libs}) list(FIND _targets "${_lib}" _idx) if (NOT _idx EQUAL -1) get_property(_inc_dirs TARGET ${_lib} PROPERTY MY_INTERFACE_INCLUDE_DIRECTORIES) set_property(TARGET ${_target} APPEND PROPERTY INCLUDE_DIRECTORIES "${_inc_dirs}") # to prevent cyclic dependencies getting us into an endless loop # remove the target we already processed from the list list(REMOVE_AT _targets ${_idx}) my_update_depending_inc_dirs("${_targets}" "${_target}" "${_lib}") endif() endforeach() endfunction(my_update_depending_inc_dirs) function(my_update_inc_dirs) get_property(_targets GLOBAL PROPERTY GLOBAL_TARGETS) list(REMOVE_DUPLICATES _targets) foreach(_target ${_targets}) my_update_depending_inc_dirs("${_targets}" "${_target}" "${_target}") endforeach() endfunction(my_update_inc_dirs)
Tested with the following code (NOTE: calling my_update_inc_dirs() at the end is required):
CMakeLists.txt
cmake_minimum_required(VERSION 2.6) project(TargetIncludeDirectories) ... add_library(PLib plib/source/plib.cpp) target_include_directories(PLib PRIVATE plib/source PUBLIC plib/include) add_library(Lib lib/source/lib.cpp) target_include_directories(Lib PRIVATE lib/source PUBLIC lib/include) target_link_libraries(Lib PRIVATE PLib) add_executable(App main.cpp) target_include_directories(App PRIVATE . PUBLIC include) target_link_libraries(App PRIVATE Lib) my_update_inc_dirs()