The VXL Project

> -----Original Message-----
> From: vxl-maintainers-admin@...
> [mailto:vxl-maintainers-admin@... Behalf
> Of Amitha
> Perera
> Sent: Wednesday, January 07, 2004 6:53 PM
> To: vxl-maintainers@...
> Subject: [Vxl-maintainers] Changing build order of libraries
>
>
> Hi all
>
> Our current build order in the CMakeLists.txt tries to build libraries
> before their dependencies are built. This makes it difficult to build
> just a single library. For example, running "make" in core/vil tries
> also to build core/vil/algo, core/vil/io, core/vil/examples, and
> core/vil/tests. Some of these will fail if other parts of the library
> haven't been built yet: tests depends on testlib, examples may depend
> on other things.
>
> I think a good solution would be to move all the SUBDIR commands to
> the core/CMakeLists.txt file. So, this file will have a format like
>
> # Level 1 libraries
> SUBDIRS( vpl )
> SUBDIRS( vsl )
> ..
>
> # Level 2 libraries
> SUBDIRS( vnl/io )
> SUBDIRS( vnl/algo )
> SUBDIRS( vgl/io )
> SUBDIRS( vgl/algo )
> ..
>
> # Test cases
> IF( BUILD_TESTING )
>   SUBDIRS( testlib/tests )
>   SUBDIRS( vnl/tests )
>   SUBDIRS( vil/tests )
>   ...
>   SUBDIRS( tests )
> ENDIF( BUILD_TESTING )
>
> # Examples
> IF( BUILD_EXAMPLES )
>   SUBDIRS( vnl/examples )
>   SUBDIRS( vil/examples )
>   ...
>   SUBDIRS( examples )
> ENDIF( BUILD_EXAMPLES )
>
> Comments?

I quite like going into core's sub directories, typing make, and having the
tests and examples subdirectories build as soon as the library is finished.

I'd agree that having to build vnl_algo before I can run vnl/tests is
annoying. The solution there is to move all the vnl_algo tests into
vnl/algo/tests.

In general, I doubt there is an globally ideal build order. One possible
solution would be to modify cmake so that it inserts tests into the
Makefile, such that
make noSUBDIR
would have the desired effect.

Until then, can I suggest Ctrl-C.

Ian.



>
> Amitha.
>
>
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Ian Scott wrote:
> I quite like going into core's sub directories, typing make, and having the
> tests and examples subdirectories build as soon as the library is
> finished.

Yes. And the reason this sounds good is that one normally expects that
if the library builds successfully, then the tests and examples will
build successfully. This is not currently true.

As you suggest,

> The solution there is to move all the vnl_algo tests into
> vnl/algo/tests.

is one solution. However, we still have a potential inconsistency
between build order and dependency order. Ideally, the two should be
consistent.

> In general, I doubt there is an globally ideal build order.

There may be no single best solution, but I think there are ones
better than what we have now. As I wrote above, build order should be
consistent with dependency order.

> One possible solution would be to modify cmake [...]

I've suggested previously to the CMake community that CMake has enough
knowledge to ensure the build order in a Makefile matches the
dependency order of the libraries. I believe they are considering it
for CMake v 2.

> Until then, can I suggest Ctrl-C.

You may. However, that is a stop gap solution that makes no attempt at
understanding or solving the underlying problem.

Amitha.

> I think a good solution would be to move all the SUBDIR commands to
> the core/CMakeLists.txt file.

I agree with this.

If someone still wants to build in all sudirectories, he can still do

    for d in `find . -type d` ; do ( cd $d ; make ) ; done

--	Peter.

Ian pointed out that it is good to have the tests build automatically
when you change the library. I agree with him. I thus modify my
proposal a little bit:

- Divide the tests so that the tests for a given library are only
  dependent on that library. This implies the tests of vnl and
  vnl_algo are different, for example, and will exist in different
  places.

- Building a library will also recurse to the tests and build
  those. The tests should, in general, only depend on the library
  being tested and on testlib.

With this done, the core/CMakeLists.txt will look something like

   SUBDIRS( testlib )
   SUBDIRS( vul )  # build libvul and vul/tests
   SUBDIRS( vnl )  # build libvnl and vnl/tests
   ...
   SUBDIRS( vnl/algo )  # build libvnl_algo and vnl/algo/tests
   ...
   SUBDIRS( vnl/examples )
   ...

Any objections to this idea? 

I can't promise a date by which I'll do this. If there are no
objections, I will do it sometime. Anyone else should feel free to do
it before me.

Amitha.