[CMake] Using ExternalProject_Add when CMakeFiles.txt is not in the root directory.

[Klaim - Joël Lamotte]

On 17 July 2015 at 20:06, Bradley Lowekamp <blowekamp at mail.nih.gov> wrote:

> Hello,
>
> David Cole just said the solution in another post.
>
> You can split the project into two, with the first one being just the
> download step, the second is the configuration and build. This should allow
> you to configure the paths for your project correctly.
>
>
I am not 100% sure that the split can solve this problem too, but I will
try it.

Now that I have the split trick in mind, it seems to match my initial
assumption that ExternalProjects should have a "download only"
function/macro
separated from the other steps, so that it is possible to compose complex
setup in easier ways than hacking ExternalProjects_Add parametters and
using clunky patches.


> I need to do this for my project too. Thanks for the question to get me
> paying attention here, and finding the answer is another post :)
>
> Brad
>
> On Jul 14, 2015, at 5:14 PM, Klaim - Joël Lamotte <mjklaim at gmail.com>
> wrote:
>
> I am attempting to use ExternalDependencies_Add with the last Protobuf
> version (v3.0.0) which is in alpha3 (I'm using the master branch
> actually)[1].
> If you don't already know: contrary to previous Protobuf version, v3.x
> provides
> cmake scripts (and also makes CMake's FindProtobuf module unusuable if you
> build Protobuf using CMake BTW).
>
> I am having trouble figuring out how to ExternalProject_add work in this
> case:
> the CMakeFiles.txt is not in the root directory of Protobuf sources, it is
> in ./cmake/ [2]
> So at build time, after download, I obviously get:
>
> >CUSTOMBUILD : CMake error : The source directory
> "blahblah/install_protobuf" does not appear to contain CMakeLists.txt.
>
> I tried several approaches using this as a base:
>
> ExternalProject_Add( install_protobuf
>     PREFIX ${NETRUSH_DEPENDENCIES_DIR}/protobuf
>     GIT_REPOSITORY https://github.com/google/protobuf.git
>     GIT_TAG master
>
>     CMAKE_CACHE_ARGS
>         -DBUILD_TESTING:bool=FALSE
> )
>
>
> I tried setting SOURCE_DIR but failed to make it work mainly because I'm
> not sure what value to set exactly, and
>
>    SOURCE_DIR cmake
>
> Does not seem to work.
>
> I was wondering if there is some args I could pass to CMake using
> CMAKE_ARGS
> but from the cmake[3] page in the doc I don't see anything that match
> exactly, or
> I might be misunderstanding something.
>
> I found this recommandation from Miklos Espak from 8th February 2015:
> "Specify a patch command that creates a toplevel cmake list with one
> 'add_subdirectory(A)'  line."
>
> It seems to work, but it also means that the repository is modified, which
> is something
> I want to avoid. Also it's really a hack for passing the right working
> directory to cmake.
>
> Is there a simpler way to do it that I missed?
>
> Thanks for your time.
>
> Joël Lamotte
>
>
> [1] https://github.com/google/protobuf
> [2] https://github.com/google/protobuf/tree/master/cmake
> [3]
> http://www.cmake.org/cmake/help/v3.3/manual/cmake.1.html#manual:cmake(1)
> --
>
> 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:
> http://public.kitware.com/mailman/listinfo/cmake
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/cmake/attachments/20150718/d42e46e5/attachment.html>