[CMake] Include XYZ.cmake from external project

[Nicholas Braden]

To solve the dependency order problem, generally you would make a
superbuild which builds your dependencies and also your own project
via ExternalProject, using the DEPENDS option to guarantee build
order. This way all your dependencies are fully built and installed
before it even gets to configuring your own project.

On Fri, Apr 8, 2016 at 3:25 PM, Matthias Möller <mmoelle1 at gmail.com> wrote:
> Dear all,
>
> I have difficulties including a XYZ.cmake file from an external project.
>
> ExternalProject_Add(MTL4
>     SVN_REPOSITORY    https://simunova.zih.tu-dresden.de/svn/mtl4/trunk
>     SVN_USERNAME      guest
>     SVN_PASSWORD      guest
>     SVN_TRUST_CERT    1
>     TIMEOUT           180
>     PREFIX            ${CMAKE_BINARY_DIR}/external/MTL4
>     CONFIGURE_COMMAND ""
>     BUILD_COMMAND     ""
>     INSTALL_COMMAND   “"
> )
>
> ExternalProject_Get_Property(MTL4 source_dir)
> set(MTL4_INCLUDE_DIRS ${source_dir})
> set(MTL_DIR ${source_dir})
>
> # Include MTLConfig from the unpacked(!!!) MTL4 library
> include("${source_dir}/MTLConfig.cmake" OPTIONAL RESULT_VARIABLE
> MTLCONFIG_FOUND)
>
>
> # MTL4 is a header-only library, hence downloading and unpacking is
> sufficient
> add_executable (demo demo.cxx)
> add_dependencies(demo MTL4)
>
> The problem is, that in a fresh build the MTL4 library is not yet unpacked,
> and hence, the MTLConfig.cmake file is not available.
> How can I “include(…)” a cmake file which is only available after the
> external project has been processed?
>
> Kind regards,
> Matthias
>
>
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