Hello Eric, The minimal example was just to display the expansion error. In real life the code uses a Boolean variable (and the rest of the CMake code is much larger as well). It was just to show the expansion error you get if you try to use a conditional generator expression inside a target_link_libraries function.
I do agree that using it would be simpler if I could use: $<$<CONFIG:Debug>:${MYLIBS_DEBUG}> $<$<CONFIG:Release>:${MYLIBS_OPTIMIZED}> But since I use a third party find module the MYLIB_LIBRARIES variable is not separated into these categories. I was hoping to avoid rewriting this external find module. Regards, Björn From: Eric Noulard <eric.noul...@gmail.com> Sent: Thursday, October 4, 2018 4:37 PM To: Björn Blissing <bjorn.bliss...@vti.se> Cc: CMake Mailinglist <cmake@cmake.org> Subject: Re: [CMake] Trouble with conditional generator expression inside target_link_libraries Le jeu. 4 oct. 2018 à 16:06, Björn Blissing <bjorn.bliss...@vti.se<mailto:bjorn.bliss...@vti.se>> a écrit : Hello, I am having trouble with a conditional generator expression inside target link libraries, which seems to expand incorrectly (or at least not the way I expect). In short, I have a list of libraries that is found by a CMake module. The list is composed of a number of elements each preceded by “optimized” or “debug”, depending on if there are built for release or debug. These libraries should only be included if a boolean is set to true. I have tried to write a generator expression which only includes the list of libraries if this variable is set. But it seems that this expression gets expanded wrong. If I try to condense the problem to a minimum example, it would be something like this: LIST(APPEND MYLIB_LIBRARIES optimized foo) LIST(APPEND MYLIB_LIBRARIES debug foo_d) TARGET_LINK_LIBRARIES(target_name PUBLIC $<$<BOOL:TRUE>:${MYLIB_LIBRARIES}> ) I don't quite understand your usage here. The genex $<BOOL:TRUE> is always true? You must have something like: $<$<BOOL:${CONDVAR}>:${MYLIB_LIBRARIES}> with CONDVAR computed before that to HOLD TRUE/1 or FALSE/0 or something similar? I would try to build a proper MYLIBS_DEBUG and MYLIBS_OPTIMIZED list out of your MYLIB_LIBRARIES var and then: target_link_libraries(target_name PUBLIC $<$<CONFIG:Debug>:${MYLIBS_DEBUG}> $<$<CONFIG:Release>:${MYLIBS_OPTIMIZED}> which may be easier to read. Or may be I missed something in your explanation. This generator expression makes my target depend of the following libraries for the release build: foo.lib & optimized.lib And for the debug build: foo_d.lib, foo.lib & optimized.lib Which is obviously incorrect. Replacing the generator expression with an IF-statement instead works. But I would like to stick to generator expressions if possible to keep my CMake code consistent. How should I rewrite my generator expression to get the correct expansion? Regards, Björn -- Powered by www.kitware.com<http://www.kitware.com> Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Kitware offers various services to support the CMake community. For more information on each offering, please visit: CMake Support: http://cmake.org/cmake/help/support.html CMake Consulting: http://cmake.org/cmake/help/consulting.html CMake Training Courses: http://cmake.org/cmake/help/training.html Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Follow this link to subscribe/unsubscribe: https://cmake.org/mailman/listinfo/cmake -- Eric
-- Powered by www.kitware.com Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Kitware offers various services to support the CMake community. For more information on each offering, please visit: CMake Support: http://cmake.org/cmake/help/support.html CMake Consulting: http://cmake.org/cmake/help/consulting.html CMake Training Courses: http://cmake.org/cmake/help/training.html Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Follow this link to subscribe/unsubscribe: https://cmake.org/mailman/listinfo/cmake