Thank you all for the help. I finally use a way quite similar to David's first approach. I first generate all sub-projects into object libraries using add_library(lib1 OBJECT SOURCES). Then in the final library, I use add_library(single_static_lib STATIC SOURCES) and target_link_libraries( single_static_lib lib1 lib2 ...). Note that I didn't use " $<TARGET_OBJECTS:lib1>" in the final "add_library" and also didn't use "PUBLIC" keyword in the final "target_link_libraries". It works on CMake v3.12.2 and gives me a single static lib which combines all the objs I want.
But currently I still have problems of further combining third party static libraries into the final generated static single_static_lib. Can anybody provide a solution for this? Thank you very much. Ke On Fri, Sep 21, 2018 at 6:15 AM Deniz Bahadir <dbaha...@benocs.com> wrote: > Am 21.09.2018 um 09:33 schrieb David Jobet: > > Hello, > > > > I had a similar issue lately and wanted to "pack" several static libs > > into a dynamic one. (Not even talking about an INTERFACE lib since I > > really wanted that .so) > > I made it work with 3 different solutions, none of them being "clean" > > from my point of view. > > > > 1- OBJECT libs on sub projects : add_library(lib1 OBJECT SOURCES) and > > for the single static lib : add_library(single_static_lib STATIC > > $<TARGET_OBJECTS:lib1> ...) > > Problem I faced : since OBJECT libs do not support > > target_link_libraries(), I had to remove the existing one and move > > them instead to the target_include_directories() using generators. > > This is no longer true. Since CMake 3.12 `target_link_libraries` fully > supports OBJECT libraries. You just need to pay attention to the special > case of linking an OBJECT library with keyword "PUBLIC". (Object-files > are always private and inherited object-files are therefore never > further inherited. See: > > https://cmake.org/cmake/help/v3.12/command/target_link_libraries.html#linking-object-libraries > ) > > > e.g : target_include_directories(lib1 PUBLIC > > $<TARGET_PROPERTY:another_lib,INCLUDE_DIRECTORIES>) > > Because I had a dependency to a protobuf generated lib, I also had to > > add manual add_dependencies to respect proper build order. > > Not clean at all > > > > 2- add_library(mysharedlib STATIC CMakeLists.txt) > > target_linked_libraries(mysharedlib PUBLIC lib1 ...) > > Maybe the cleanest way I found. > > The trick with CMakeLists.txt is that add_library needs at least one > > source file. You can put any kind of files you want. CMakeLists.txt is > > not compilable, so no extra compilation step, no need for dummy empty > > source file and add_library is happy. > > It did not work in my case because of problems related to how our .so > > are used/generated. (problems at runtime with duplicated symbols in > > protobufs) > > > > 3- a variation around 1 > > instead of defining OBJECT libs, define a variable holding all the > > sources for lib1, another for lib2, ... > > then just do add_library(mysharedlib STATIC ${SOURCES_FOR_lib1} > > ${SOURCES_FOR_lib2}) > > It works a little bit like 1) but does not have any of its problems > > (target_link, add_dependencies, generators, ...) > > It has new problems of its own though : if your libs live in different > > subfolders, the variables might not be visible from your > > add_library(mysharedlib...) call. > > To work around that, you can use PARENT_SCOPE (not sure if that works > > accross several levels), or includes (defines those variables into > > separate files living in each subfolders and include them in the > > parent CMakeLists). > > > > Hope this helps (and I'd be happy to know of other ways) > > > > David > > On Thu, Sep 20, 2018 at 5:45 PM Ke Gao <ke.gao...@gmail.com> wrote: > >> > >> Hi, > >> > >> I have a project which includes many sub-projects. Each sub-project > generates a static library. In the main project, I want to combine the > generated objs, generated static libraries from other sub-projects, and > some other third party static libraries together into a single static > library. Is there an elegant way to do this, or maybe an existing function? > >> > >> Thank you very much. > >> > >> -- > >> > .............................................................................................................................................. > >> Ke Gao > > > Hope that information was of value, > Deniz > > -- > > 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 > -- .............................................................................................................................................. Ke Gao
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