[CMake] Advice for CMake_import_build_settings

[Mathieu Malaterre]

On Fri, May 23, 2008 at 5:46 PM, Brad King <brad.king at kitware.com> wrote:
> Blezek, Daniel J., Ph.D. wrote:
>>
>>  I'd like to build and install Insight (though the toolkit is not
>> important) using GCC.  Then I want to build applications using GCC, the
>> Intel compiler, and IBM's XLC compiler.  All should be able to use the
>> GCC-build libraries.  However, CMAKE prohibits this with the
>> CMake_import_build_settings command, which forces the project to change it's
>> compiler, and consequently wreaking havok on my CMakeCache.  This is really
>> frustrating.  I have to build and install 3 versions of Insight, when only
>> one is really needed.
>>
>>  My question: Is this behavior strictly necessary?  I can see it may have
>> utility on Windows, but makes less sense in Linux, especially in our case.
>>  Is it possible to augment or override this command, or do I pick it out of
>> our installed libraries?
>
> It used to be necessary to keep inexperienced users from mixing ABIs.
> However, modern C++ compilers (within the last 5 years or so) have a more
> standard ABI so it's not a problem.  In CMake 2.6 you can override the
> behavior by using
>
>  set(CMAKE_OVERRIDE_COMPILER_MISMATCH 1)
>
> before including ITK.  Alternatively for any CMake version you can write
>
>  find_package(ITK REQUIRED)
>  set(ITK_BUILD_SETTINGS_FILE)
>  include(${ITK_USE_FILE})
>
> The middle line tells the UseITK.cmake file to skip the build settings step.
>
> In the future I plan to get rid of this stuff from ITK and VTK in favor of
> something more reliable.

+1


-- 
Mathieu