Philipp Möller wrote: > Stephen Kelly <steve...@gmail.com> writes: > >> Philipp Möller wrote: >>> It would be great, if I could export imported targets and if CMake could >>> walk the dependency tree automatically and import those targets on an >>> as-needed basis. >> >> Part of the problem is that the place where you import your dependent >> targets from (and the locations calculated) are not necessarily the same >> for your downstreams. > > I understand the issue and have been fighting it in versions prior 3.0 > as well. It also arises if you simply export targets that have been > target_link_librarie'd against full library paths returned by a > find_package.
Yes, exactly. That's the problem with having paths in INTERFACE_LINK_LIBRARIES, and a good reason not to do that. > That's why I thought some build-in functionality could be helpful for > this, e.g. exporting and imported target would lead to a definition in > the exports file that automatically triggers a corresponding > find_package call. Seems overly-complex to implement. >> You export your targets to and -exports file, and presumably you import >> that in a -config file. In the same config file, you should add code to >> find your dependencies too. >> >> >> http://www.cmake.org/cmake/help/v3.0/manual/cmake-packages.7.html#creating-packages >> >> The find_dependency macro can help with forwarding some find_package >> arguments. >> >> http://www.cmake.org/cmake/help/v3.0/module/CMakeFindDependencyMacro.html > > The documentation is a little sparse, but I think I understand the > purpose. The code is easy to read, if that helps. However, it's not designed for your complex case (it deliberately doesn't wrap all arguments of find_package), so you may have to do something similar to it on your own. > I still need to traverse IMPORTED_LINK_INTERFACE_LIBRARIES and > figure out which of the list members constitutes a target that needs to > trigger a find_dependency and what a full library path is, correct? No, I don't think so. You shouldn't introspect IMPORTED_LINK_INTERFACE_LIBRARIES like that. Simply issue a find_dependency call and ensure that the package can be found. That probably means writing (and shipping with your config file) a Find-module for your dependency which creates the needed imported targets. > I can also not rely on a find_package call to actually produce imported > targets and need to ship the code that turns the results of find_package > in targets. You can actually. You just need to write and ship such a Find-module yourself (until the necessary imported targets are provided by the Find- module itself). Create a wrapper around the relevant Find-module and add the imported targets. Something like: # FindFoo.cmake find_package(Foo PATH ${CMAKE_ROOT}/Modules NO_DEFAULT_PATH) add_library(Foo::Lib SHARED IMPORTED) # ... and in the config file: find_package(Foo ${maybe_other_args} PATH ${CMAKE_CURRENT_LIST_DIR} NO_DEFAULT_PATH) If you are going to write proper IMPORTED targets for cmake-shipped Find- modules, I'd recommend contributing them to cmake instead anyway. Thanks, Steve. -- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://public.kitware.com/cgi-bin/mailman/listinfo/cmake-developers
