[CMake] Swig dependencies not being tested?

[Tristan Carel]

On Dec 10, 2007 7:15 AM, Alan W. Irwin <irwin at beluga.phys.uvic.ca> wrote:
> On 2007-12-10 05:33+0100 Christiaan Putter wrote:
>
> > Hi all,
> >
> > I know swig support isn't all that great at the moment but was wondering if
> > someone happens to have a working Swig module for cmake that doesn't rebuild
> > every time even without the dependencies having changed.
>
> I do confirm that is a problem, and I hope somebody fixes it.
>

I use the Swig module, the one provided by CMake, and it's working
well. Swig wrappers generation and library compilation are properly
managed (not rebuild all the time). I use it the same way than Alan
described: only one swig file, which takes care of all inclusions, is
provided to the macro SWIG_ADD_MODULE. To specify missing
dependencies, I use the variable `SWIG_MODULE_<module>_EXTRA_DEPS':

SET(SWIG_MODULE_foo_EXTRA_DEPS bar.i foobar.i bar.h ...)
SWIG_ADD_MODULE(foo PYTHON foo.i)


Attached to #4147, you can  find a macro
`SWIG_GET_WRAPPER_DEPENDENCIES' which use -MM option provided by Swig
to compute dependencies. This intend to replace use of variable
SWIG_MODULE_<module>_EXTRA_DEPS


Could you please describe a use case which create the unnecessary
rebuilt of your project?

> >
> > Someone else also pointed out a problem with .i files having to be in the
> > current source dir.
>
> We have never felt constrained by that limitation (in fact I was unaware of
> it) since it is possible to specify just one *.i file in the current source
> directory that then includes *.i files from elsewhere in the source tree.

+1

> Despite the convenience of this approach, others will have different needs
> that would best be served by allowing the initial *.i file (that includes
> the rest of the *.i files) to be somewhere else than the current source
> directory so on these general grounds I hope this limitation is removed
> at the same time as when the dependency problem is fixed.

I agree, it should work.
I guess it is alright if you specify a path like "../common.i" but not
something like ${CMAKE_SOURCE_DIR}/swig/common.i.

-- 
Tristan Carel
Music with dinner is an insult both to the cook and the violinist.
http://www.tristancarel.com