Adding the interface of a library to the private include path of another target

Usage
1

Hi,

is there a built-in method to add the (complete) interface of a library to the private include directories of another target (i.e. the include path used when compiling that target)?

Example:

  • lib1: non-INTERFACE_ONLY library which has header1.h in its interface
  • lib2: non-INTERFACE_ONLY library which has header2.h in its interface; header2.hcontains #include "header1.h"
  • executable: one of its .c files contains #include "header2.h"; no link dependency on lib2 or lib1

Approach:

get_target_property(lib2_interface lib2  INTERFACE_INCLUDE_DIRECTORIES)
target_include_directories(executable PRIVATE ${lib2_interface})
  • Would this work reliably? I mean:
    • regardless of the order in which the lib1, lib2, and executable targets are defined
    • transitively (pulling in also the interface of lib1 without explicitly having to specify that dependency in the executable target)
  • Is there a better method to add lib2ā€™s (and transitively also lib1ā€™s) interface directories to the include directories used when compiling executable?

Kind regards
Ingolf

2

Maybe, you can use the following pattern:

target_link_libraries(executable PRIVATE "$<COMPILE_ONLY:lib2>")

For more information, see $<COMPILE_ONLY:ā€¦> help.

1 Like
3

Thanks, Marc, for this hint. I had not been aware of that generator expression.

Unfortunately, we are currently more or less bound to using CMake 3.21.x, so Iā€™d still be interested in an assessment as in my first question.