[CMake] in- and out-of-source tree builds

[Bill Hoffman]

Orion Poplawski wrote:
> Various projects using cmake state that they don't support in source 
> tree builds.  Is this a general case for cmake projects?
>
No, it is not a general case.   CMake itself can be built either way.
> We're working on packaging guidelines for cmake projects in Fedora. 
> Draft is here: http://fedoraproject.org/wiki/PackagingDrafts/cmake. 
> Currently this does an in source tree build.
>
> I currently do:
>
> mkdir fedora
> pushd fedora
> cmake ..
>
> In which the build directory is a subdirectory of the source tree.  
> I've also seen recommendations for a parallel directory, e.g.:
>
> cmake ../source
>
> Is this preferred over the former?
Both of these cases are considered out-of-source builds.   Both should 
work equally well.  In source would be:
cd source
cmake .

>
> What are the issues that arise?  In general with RPM packaging you are 
> starting with a clean freshly unpacked source tree.
It really depends on the project.  There are no cmake imposed 
limitations on this.


-Bill