[CMake] Internal propagation of usage requirements

[Lukas Böger]

Dear cmake-Gurus,

When unit tests and an exported library shall be compiled with identical _private_ settings (include directories, compiler flags etc.), I see these options:

(1) define variables to be passed to target_* functions for both library and test target
    + simple solution
    - violates avoid-variables-idiom
    - possibly uses "non-local" variables defined in another CMakeLists.txt (reduces readability)

(2) link both library and test targets against an internal, usage-requirement-only interface library
    + modern approach, no variables, only target_* functions invoked
    - when compiling a static library, the internal target must be exported, too (though "filtered" by LINK_ONLY later on)

(3) retrieve lib properties via get_property, then propagate them via target_* functions
    + variables in use have a "local" scope of the CMakeLists.txt
    - verbose and clumsy

Am I missing a solution? Which one is preferable and why? Any pro/cons that I haven't seen?

Thanks for any advice!

Best,
Lukas
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://cmake.org/pipermail/cmake/attachments/20180608/07ede92d/attachment.html>