[CMake] CMake: using dlopen

[Franck Houssen]

And so, if I have an executable (add_executable), the default thing to do is to use target_link_libraries(mylib PRIVATE ...). Not PUBLIC (as I do). Correct ?

----- Mail original -----
> De: "Franck Houssen" <franck.houssen at inria.fr>
> À: "Rainer Poisel" <rainer.poisel at gmail.com>
> Cc: "CMake Mail List" <cmake at cmake.org>
> Envoyé: Lundi 8 Janvier 2018 10:41:25
> Objet: Re: [CMake] CMake: using dlopen
> 
> 
> 
> ----- Mail original -----
> > De: "Rainer Poisel" <rainer.poisel at gmail.com>
> > À: "Franck Houssen" <franck.houssen at inria.fr>
> > Envoyé: Dimanche 7 Janvier 2018 19:34:21
> > Objet: Re: [CMake] CMake: using dlopen
> > 
> > Hi,
> > 
> > On Sun, Jan 7, 2018 at 7:13 PM, Franck Houssen <franck.houssen at inria.fr>
> > wrote:
> > > Difference between PUBLIC/PRIVATE has never been clear to me (usually I
> > > always use PUBLIC).
> > > main.cpp includes dlfcn.h and uses it: not sure to get what you meant
> > > (PRIVATE is for templates ? when a header include headers ?)
> > 
> > you are looking for the "Transitive Dependencies" feature of CMake:
> 
> OK, I didn't get that. It's more clear to me now. Thanks !
> 
> >   *
> >   https://cmake.org/cmake/help/v3.0/manual/cmake-buildsystem.7.html#transitive-usage-requirements
> > 
> > Generally speaking and from my personal experience, use the
> > target_-commands as much as possible because properties are bound to
> > targets and their dependencies rather than a file/directory structure.
> > 
> > So, that means, use target_include_directories(),
> > target_compile_options(), target_compile_definitions(),
> > target_sources(), ... for your targets. The magic keyword to propagate
> > the properties of your targets is target_link_libraries(). Depending
> > on what scope (PRIVATE, PUBLIC, INTERFACE) the properties have been
> > defined using the other target_-commands, the target_link_libraries()
> > command propagates these properties to other targets. E. g.
> > 
> > add_library(otherlib SHARED
> >   foo.c
> > )
> > 
> > target_include_directories(otherlib PRIVATE
> >   dirPrivate
> > )
> > 
> > target_include_directories(otherlib PUBLIC
> >   dirPublic
> > )
> > 
> > add_library(mylib SHARED
> >   bar.c
> > )
> > 
> > target_link_libraries(mylib PRIVATE
> 
> Is this a typo ?
> For the example to work I would have done: target_link_libraries(mylib PUBLIC
> otherLib), no ? (mylib needs only PUBLIC stuff's from otherLib but not
> PRIVATE one's). Correct ?
> 
> 
> >   otherlib
> > )
> > 
> > In this case, mylib will use all PUBLIC or INTERFACE properties of
> > otherlib for its build. Thus, dirPublic will be added to the include
> > directory search path for the compilation of bar.c of mylib. PRIVATE
> > properties will not be propagated. In the above mentioned example,
> > dirPrivate will NOT be added to the include directory search path for
> > the compilation of bar.c of mylib.
> > 
> 
> The example is illustrative (transitivity - PRIVATE is not propagated)
> 
> > This is a very short summary, but I hope it is of help to you. There
> > are other ressources on the Internet. E. g.
> >   *
> >   https://stackoverflow.com/questions/26037954/cmake-target-link-libraries-interface-dependencies
> >   * https://rix0r.nl/blog/2015/08/13/cmake-guide/
> > 
> > Regards,
> >   Rainer
> > 
> --
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