[CMake] setting different include_directories, link_directories, etc for different targets

[Michael Jackson]

Just thinking out loud here so none of this may work.

You _could_ potentially have the same "target" compiled for 2  
different platforms but this generally goes against the general CMake  
workflow. I guess you could have a tope level CMakeLists.txt file that  
has something like:

# Make this a cache variable so it shows in the cmake-gui
set (PLATFORMS "" CACHE STRING "Semi-colon separated list of Platforms  
to compile for")

# Assume We have 3 subdirectories called Proj1, Proj2, Proj3
set (MyProjects "Proj1;Proj2;Proj3")

foreach(proj ${MyProjects})

   foreach(platform ${platforms})
      set(ActivePlatform ${platform} CACHE STRING "The current  
platform being configured" FORCE)
      add_subdirectory(${proj} ${CMAKE_CURRENT_BINARY_DIR}_${platform} )

   endforeach()
endforeach()


So the user needs to enter a list of platforms that they want to  
compile for as a semi-colon separated list. Now, in the CMakeLists.txt  
file in the "Project" subdirectories you will need something like the  
following:


add_executable( Proj1_${ActivePlatform}  .... )
target_link_libraries(Proj1_${ActivePlatform} ...)

if ( ${ActivePlatform} STREQUAL "WinCE")
  set_target_properties( roj1_${ActivePlatform} ... ....)
elseif( ${ActivePlatform} STREQUAL "Win32")
  set_target_properties( roj1_${ActivePlatform} ... ....)
endif()


All this is an abuse of how CMake is supposed to work in my opinion  
but may work for you.

It is better to have a completely separate build directory for each  
type of build. Try the code and see if it will work for your situation.

---
Mike Jackson                 www.bluequartz.net



On Mar 26, 2009, at 9:46 AM, Kuba Bican wrote:

> Thanks for quick answers.
>
> So one of the basic problems is that it is not possible to build the
> same file several times in different targets? (Because the object
> files would collide?) Then it makes me sense that the properties can
> be set on directories and not on targets.
>
> OK, I can configure a separate project for each platform. For that it
> would be helpful to have:
> * multi-choice option in CMake to select from available platforms. Or
> is there some good workaround if multi-choice options are not
> available.
> * and finally, to somehow include all generated projects in single
> solution. Or such thing has to be done manually?
>
> Thanks again. Regards,
>
>    Jakub
>
>
>
> 2009/3/26 Denis Scherbakov <denis_scherbakov at yahoo.com>:
>>
>> Jakub,
>>
>> I don't really understand, how it is possible, to share the same  
>> build directory with WIN32 object files and say Sparc-Solaris?
>>
>> Even, if you only talk about windows variations, how will you  
>> distinguish, file WindowUtilApp.obj was compiled for WinXP or WinCE?
>>
>> At build time - it is NOT possible to share build directories. At  
>> install time - you can specify common installation directory for  
>> all build trees, say C:\Project\BIN and perform installation of  
>> executables there, but you'll have to make sure that executable  
>> names still differ. Otherwise they will overwrite each other.
>>
>> Denis
>>
>>
>>> Yes, this is one of the possibilities which does not solve
>>> the problem
>>> very nice ... or is it possible to have the final generated
>>> projects
>>> in one solution, with one "BUILD_ALL" and
>>> "RUN_TESTS" and all the
>>> things around?
>>
>>
>>
>>
>>
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