CMake Proposal

[Bill Hoffman]

Hi,

Dan Shearer asked me to join the discussion about Samba using CMake as a 
build system.  I am a CMake developer, and of course would be very happy 
if Samba were to adopt CMake as a build tool.

I have read the thread on this list and would like to address some of 
the questions that came up.

-  command line interface to CMake and -Dvar=value is verbose

This is true, and there has been talk about creating a more natural 
--var type interface for CMake projects.  I suspect we will implement 
one of these options at some point in the future, however, I would not 
see this as a show stopper.  cmake-gui and ccmake are good ways to 
handle the options in a CMake project interactively.

- You want to be able to do this:
   make test TESTS=regex
   make testenv

   For the first one, in CMake, that would be done with

make test ARGS="-R regex"

I am not sure what make testenv does, so I can not yet comment on that 
one...

- binary builds of CMake
   We produce binaries for various platforms that can be found here:
http://www.cmake.org/cmake/resources/software.html

The linux binary is static and built on a VERY old version of linux and 
is there for compatible with just about every version of linux we have 
seen.  Please let me know if you find an intel linux system where it 
does not run.  We also support the big commercial UNIX vendors as well. 
You can see that on the dashboard:
http://www.cdash.org/CDash/index.php?project=CMake

If you have other platforms you need like True64, I would be very happy 
if you could do nightly CMake builds.


- cross compile questions
   CMake does have cross compiling support, to support code generators, 
you create two build trees, one for the host and one for the target. 
The target build tree can "import" built targets from the host system, 
and use them as code generators.

- adding unsupported compilers
It should be possible to add new compilers without changing the CMake 
binary.  The support files for the compiler can be put into Samba 
itself, and later ported to CMake.

- A request for non-timestamp based file comparison.

I think this one conflicts with this comment: "scons horribly slow over 
CMake ", I suspect that the checksums might be part of that problem. 
However, the use case given was a header file generator program that is 
modified, and then regenerates all of the header files causing a big 
rebuild.   This can be avoided in a different way.  Basically, you have 
the generator create a temporary header, then a different custom command 
can use that as input, the second command uses copy if different to 
create the actual header file.   Then the header file only changes when 
it really changes.

- Blender was given as a project that uses scons, it also has a CMake 
build system...  :)

Hope this helps, and if you have any other specific questions about 
CMake, please ask.

Thanks.

-Bill