[CMake] UseSWIG creates module instead of shared library, which can't be dynamically loaded

[Mathieu Malaterre]

On Thu, Aug 6, 2009 at 2:27 PM, Stephen Roderick<kiwi.net at mac.com> wrote:
> On Aug 6, 2009, at 06:02 , Mathieu Malaterre wrote:
>
>> On Wed, Aug 5, 2009 at 6:55 PM, Stephen Roderick<kiwi.net at mac.com> wrote:
>>>
>>> The existing UseSWIG.cmake file creates a MODULE and not a SHARED
>>> library.
>>> The module is unuseable by any program trying to load dynamic libraries
>>> (eg
>>> wrapped Java). The attached patch fixes this problem for our situations.
>>> Demonstrated on both Mac OS X Leopard and Ubuntu Jaunty.
>>>
>>> Is this a known issue? I searched what I could of the list and the 'net,
>>> and
>>> couldn't find anything on this.
>>
>> No, you are confusing the C++ library and the Java binding. Instead:
>>
>> ADD_LIBRARY(foo SHARED ${foo_SRCS}) # the actual shared lib
>> SWIG_ADD_MODULE(foojni java foo.i)
>> SWIG_LINK_LIBRARIES(foojni foo
>>  ${JNI_LIBRARIES}
>> )
>>
>> The next time you will want to create -say- a python module you'll
>> simply link to your *shared C++* library:
>>
>> SWIG_ADD_MODULE(foopython python foo.i)
>> SWIG_LINK_LIBRARIES(foopython foo
>>  ${PYTHON_LIBRARIES}
>> )
>
> Unfortunately, that is what we currently have.
>
> <code>
>  ADD_LIBRARY(MyInterfaceCpp ...)
>
>  Find_Package(SWIG REQUIRED)
>  Find_Package(JNI REQUIRED)
>  INCLUDE(UseSWIG)
>  INCLUDE_DIRECTORIES(${JAVA_INCLUDE_PATH} ${JAVA_INCLUDE_PATH2})
>
>  SET_SOURCE_FILES_PROPERTIES(MyInterface.i PROPERTIES CPLUSPLUS 1)
>  # compile swig with package flag
>  SET(CMAKE_SWIG_FLAGS -package x.y.z)
>
>  SWIG_ADD_MODULE(MyInterface java MyInterface.i)
>  SWIG_LINK_LIBRARIES(MyInterface
>        MyInterfaceCpp ...)
> </code>
>
> The failure comes when you try to load the SWIG-output, JNI library from
> within java, using something like
> <code>
>        static {
>                System.loadLibrary("MyInterface");
>        }
> </code>
>
> With a module in a "MyInterface.so" file (what SWIG currently outputs), the

No. On Linux 'lib' is always preprended, even for MODULE. I am not
sure about MacOSX.

> above call fails on both Mac OS X and Linux. They both need a correctly
> named dynamic library, hence the patch.

I have been using this in gdcm and it works fine on Linux:

http://gdcm.svn.sf.net/viewvc/gdcm/trunk/Wrapping/Java/gdcm.i?r1=5779&r2=5799

2cts
-- 
Mathieu