[CMake] acyclic subdirectory builds

[Egon Kocjan]

Hi,

I have a complicated situation :). I avoided the kind of approach, that 
you suggest because it's not modular - main project file contains 
add_subdirectory commands, which have to be maintained "by hand" - you 
can see the non-modular information leak here: "add_subdirectory( liba )".

The task is to convert ~100 projects with acyclic (non-tree) 
dependencies to cmake. It would be nice to double-click on any project 
in the graph and have the build system figure out the needed 
dependencies from "lower" levels automatically. The reason that I want 
to have subgraph builds is that VS would probably break if I included 
the whole beast at once :).

regards,
Egon

Amitha Perera wrote:
> Bätge wrote:
>  >  ADD_DEPENDENCIES( exea liba )
>  >  ADD_DEPENDENCIES( exeb liba )
> 
> That should be TARGET_LINK_LIBRARIES.
> 
> Egon: as Stephan says, you want to avoid this include() stuff.  That is 
> only useful some complicated situations.  What you want is probably 
> something like this: (I added a libb for fun.)
> 
> /liba/CMakeLists.txt:
>   ...
>   add_library( liba ... )
>   ...
> 
> /libb/CMakeLists.txt
>   ...
>   add_library( libb ... )
>   ...
> 
> /exea/CMakeLists.txt
>   ...
>   add_executable( exea )
>   target_link_libraries( exea liba libb )
>   ...
> 
> /exeb/CMakeLists.txt
>   ...
>   add_executable( exeb )
>   target_link_libraries( exeb liba libb )
>   ...
> 
> /CMakeLists.txt
>   PROJECT( proj )
>   add_subdirectory( liba )
>   add_subdirectory( exea )
>   add_subdirectory( exeb )
> 
> 
> (You may be able to to the last step from a proj subdirectory, as you 
> had in your original email, but I can't remember right now if that is a 
> 2.4.x feature or a 2.6.x feature.)
> 
> If you move to CMake 2.6, you can even create self-standing sub-project 
> solutions.  (I think CMake 2.4 doesn't quite do that, but I could be 
> wrong.)
> 
> Amitha.
> 
>