[CMake] SuperBuild whoes

[Michael Wild]

On 04/21/2011 02:45 PM, David Cole wrote:
> On Thu, Apr 21, 2011 at 4:30 AM, Michael Wild <themiwi at gmail.com
> <mailto:themiwi at gmail.com>> wrote:
> 
>     On 04/21/2011 06:48 AM, Michael Wild wrote:
>     > Hi all
>     >
>     > I'm trying to set up a SuperBuild here. Everything works nicely the
>     > first time round I build the project. The only real problem I have is
>     > that if I change the sources of one of the sub-projects, the
>     SuperBuild
>     > still thinks everything is up to date. Of course, this is fully
>     > explainable by the fact that the SuperBuild knows nothing about the
>     > internal dependencies of the sub-project, and since the stamp
>     files are
>     > all there and unchanged, it thinks everything is fine. How do I get
>     > around this? Anybody got an idea?
>     >
>     > Thanks
>     >
>     > Michael
> 
> 
>     Found it myself. For completeness and documentation purposes: Add a
>     custom target which removes the *-complete (see ExternalProject.cmake on
>     where it is located, it is a bit tricky) and -*configure stamps. Of
>     course, it should always run and depend on the external project target.
> 
>     The thing I'm struggling with now is installing the various sub-projects
>     into the system. Seems like it is impossible to install an imported
>     target [1], but guessing and hard coding the paths is also not very
>     attractive, but probably the only way to go at the moment. If anybody
>     has a better idea, please speak up...
> 
>     Michael
> 
>     [1] http://www.mail-archive.com/cmake@cmake.org/msg18336.html
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> 
> 
> If your intent is *always* to run the configure and later steps of an
> ExternalProject build, you can consider adding an extra custom step that
> configure depends on, which does nothing, but ALWAYS runs... No need to
> do any fancy scrounging of stamp files for this to work.
> 
> 
> Something like:
> 
> ExternalProject_Add(Proj1
>   ...
> )
> 
> ExternalProject_Add_Step(Proj1 forceconfigure
>   COMMAND ${CMAKE_COMMAND} -E echo "This custom external project step
> forces the configure and later steps to run whenever a top level build
> is done..."
>   DEPENDEES download
>   DEPENDERS configure
>   ALWAYS 1
>   )
> 
> 
> By the way, this is how repository-based checkouts always build. A cvs,
> git or svn checkout's update step *always* runs (by default, unless you
> override UPDATE_COMMAND), and since the configure step depends on the
> update step, they also always configure, build and install.
> 
> 
> HTH,
> David
> 


Mhm, I thought I already tried this, but will check again. Thanks for
the input.

I also solved my installation problem. By having all sub-projects
install into a common prefix, and thanks to the wonders of RPATH and
install_name which can handle relative paths and thanks to the fact that
install(EXPORT) generated files are also relocatable, I can simply do a
install(DIRECTORY) in the super project ;-) The only thing that required
some thinking was writing a relocatable XXXConfig.cmake file. I think I
will update my tutorial on the WIKI to use a un-configured, relocatable
XXXConfig.cmake file.


Michael