On 12/18/2012 11:09 AM, Stephen Kelly wrote: >> At generate time that property >> will be used to accumulate values from INTERFACE_-like properties on >> the named interfaces and append them to LINK_LIBRARIES, etc. > > You wrote before that you don't propose using properties and generator > expressions:
Well, the raw properties (e.g. INCLUDE_DIRECTORIES) would initially populate the generate-time C++ structures. Then the structures would be extended after evaluating interfaces of dependencies. >> This can all be done inside C++ structures rather than with >> properties and generator expressions because it is only done during >> generation. > > That is the kind of thing I'm confused about. I don't see what value the > USE_INTERFACES property adds. 1. It puts the transitivity in one place rather than separately in each kind of build property. 2. It makes interfaces first-class rather than hidden behind linking. 3. There is no change in behavior for existing use cases because the new behavior comes only from new interfaces. > Here's some code that works with my branch (imagining a new command, and > without the USE_INTERFACES property). How would it look with your proposal? > > add_library(foo ...) > set_property(TARGET foo PROPERTY INTERFACE_INCLUDE_DIRECTORIES > $<$<CONFIG:Debug>:/foo/include> > ) > > add_executable(bar ...) > target_use_interfaces(bar INTERFACES foo) They keyword "INTERFACES" might not be the same but otherwise the example would work in my proposed approach. > The idea of a new command and the idea of a non-granular USE_INTERFACE > property are not tied together. But if you clarify what you wrote about > how/when *_INTERFACE properties would be used, that would at least get the > understanding of your proposal off the ground. In the above example the target_use_interfaces command would not do anything except append foo to bar's USE_INTERFACES property. Then at generate time for building bar, CMake would read its USE_INTERFACES and see that it needs to include the interface defined by foo. It would then go read INTERFACE_INCLUDE_DIRECTORIES from foo and append the value to bar's include directories when generating. -Brad -- 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
