[cmake-developers] Setting the link interface and dependencies in one command

[Brad King]

On 10/5/2011 9:47 AM, Stephen Kelly wrote:
> Thanks for all of your explanations. It seems that introducing a way to do
> this with one command has some support.
>
> So if SOME_FEATURE is true,
>
> target_link_libraries(foo bar SOME_KEYWORD baz)
> if (SOME_FEATURE)
>    target_link_libraries(foo mar SOME_KEYWORD maz)
> endif()
>
> would have to result in bar and mar not being part of the link interface,
> and baz and maz being part of the link interface.
>
> How do we decide on a keyword there? LINK_INTERFACE_DEPENDENCIES perhaps?

One possible problem with making it a keyword is that the name could appear
in a list of libraries and invisibly transform a target_link_libraries call.
What we need is a pair of keywords to switch between link+interface and
link-only dependencies.  We allow the keywords only if one of the two is
the second argument to the command after the target name.  For example,
they can be called "LINK_INTERFACE" for link+interface and "LINK_DEPENDS"
for link-only:

   target_link_libraries(foo LINK_INTERFACE bar LINK_DEPENDS baz)
   if(SOME_FEATURE)
     target_link_libraries(foo LINK_INTERFACE mar LINK_DEPENDS maz)
   endif()

Other possible names?  Perhaps LINK_PUBLIC and LINK_PRIVATE?
Perhaps LINK AND LINK_ONLY?

-Brad