Difference between PUBLIC and INTERFACE is not stated

[studyingegret]

Hello,

I read cmake-compile-features(7) and I couldn’t find text saying the difference between PUBLIC and INTERFACE. I think Transitive Usage Requirements should be linked here to clarify this.

[fenrir (Jakub Zakrzewski)]

The docs for target_compile_features talk about this, and I feel like that’s the right place.

[adaldev]

the usage of target_include_directories vs target_link_libraries

Hi IMHO, I partially agree for the executable part but not for the library one. First of all it does not depend on the shared/static status. Let say a lib A depends on a lib B. If the headers of A that may be included by an application that links A contains symbols from B then target_link_libraries(A PUBLIC B) otherwise target_link_libraries(A PRIVATE B) another situation may arise: B symbols are only present in A headers but are not used for A sources. then target_link_libraries(A INTERFA…

[studyingegret]

@fenrir

The docs for target_compile_features talk about this, and I feel like that’s the right place.

I agree it will be helpful to talk about it there in the section “Compile Feature Requirements”, although that section is not mainly for it (?) and it would repeat with “Transitive Usage Requirements”.

My understanding of INTERFACE is “you don’t need to use it, but it is needed when others use you”.

[studyingegret]

@adaldev So do you agree on explaining or linking it there? Could you give a clear answer?

[adaldev]

Is it what you needed?

@adaldev

I sum up it in the following way (for target_compile_definitions and target_link_libraries):
PRIVATE: the target uses the definition/dependency only to be build, not its clients
PUBLIC: the target uses the definition/dependency when it is built, its clients also use it
INTERFACE: the target does not uses the definition/dependency when it is built, but its clients use it

it’s also the same for target_compile_features by the way (just replace definition or dependency by feature)