[geos-devel] Using SWIG to interface with GEOS, undefined symbols

[Sean Gillies]

On Jul 12, 2004, at 1:13 PM, strk wrote:

> On Mon, Jul 12, 2004 at 12:15:58PM -0600, Sean Gillies wrote:
>>
>> On Jul 12, 2004, at 9:39 AM, strk wrote:
>>
>>> On Mon, Jul 12, 2004 at 09:10:53AM -0600, Sean Gillies wrote:
>>>> On Jul 12, 2004, at 9:00 AM, strk wrote:
>>>>
>>>>> On Mon, Jul 12, 2004 at 08:41:07AM -0600, Sean Gillies wrote:
>>>>>> Hi all,
>>>>>>
>>>>>> Yesterday I began to try to use SWIG to generate a Python
>>>>>> GEOS module using the CVS GEOS.  To start, I am only wrapping
>>>>>> the classes in geom.h and precision.h.
>>>>>
>>>>> precision.h does not really contain 'basic' classes.
>>>>> PrecisionModel class is in geom.h.
>>>>>
>>>>>> SWIG 1.3.20 generates wrapper code with only a few warnings
>>>>>> and the module does build, resulting in geos.py and a very
>>>>>> large _geos.so (I have statically linked against libgeos.a).
>>>>>>
>>>>>> On import of the geos module, an import error is raised:
>>>>>>
>>>>>> ImportError:
>>>>>> /home/sean/projects/PyGEOS/build/lib.linux-i686-2.3/_geos.so:
>>>>>> undefined symbol: _ZN4geos14PrecisionModel19maximumPreciseValueE
>>>>>
>>>>> Could you have built _geos.so and the geos.py in at different 
>>>>> times ?
>>>>> CVS api is changing , and you get those kind of errors for every
>>>>> simple
>>>>> 'const' addition.
>>>>>
>>>>> --strk;
>>>>>
>>>>
>>>> Thanks for the reply!  _geos.so and geos.py are synchronous, no
>>>> problem
>>>> there.  I was having this same issue with GEOS 1.0 and SWIG, so I am
>>>> ruling out API changes.  It's either my lack of knowledge of C++, 
>>>> some
>>>> undocumented SWIG issue or a combination of these.
>>>>
>>>> Sean
>>>
>>> I've checked the code. It seems a bug in both GEOS-1.0 and GEOS-CVS
>>> PrecisionModel::maximumPreciseValue is never given a value.
>>>
>>> geos::maximumPreciseValue is, but the header declare
>>> geos::PrecisionModel::maximumPreciseValue, which is not.
>>>
>>> I've fixed it, please try now.
>>>
>>> --strk;
>>>
>>
>> Yes, that one bug seems to be fixed.
>>
>> Now there is exposed another one :)
>>
>>   ImportError:
>> /home/sean/projects/PyGEOS/build/lib.linux-i686-2.3/_geos.so:
>>   undefined symbol:   _ZNK4geos14CoordinateList17toCoordinateArrayEv
>>
>> If I direct SWIG to ignore the toCoordinateArray() method of
>> CoordinateList,
>> then there is yet another undefined symbol:
>>
>>   ImportError:
>> /home/sean/projects/PyGEOS/build/lib.linux-i686-2.3/_geos.so:
>>   undefined symbol:
>> _ZN4geos14CoordinateList3addEPSt6vectorINS_10CoordinateESaIS2_EEb
>>
>> Strk, I appreciate that you have taken the time to look into it,
>> but this might be more time consuming.  I don't know if it will
>> be possible to SWIG GEOS or if it is in the project's interest to
>> be altered so that a SWIG module is possible.
>>
>> cheers,
>> Sean
>
> Sean, no problem, you might help us as well, as we are redefining
> the API, so every feedback is appreciated.
> The problem here is with CoordinateList being currently removed
> from interface. CoordinateList class reference is still in the
> geom.h file, but the corresponding module is not built into
> the library. We are still discussing wheter to keep or not that
> class. In the meanwhile, I commented out the definition,
> this should fix your problem.
>
> --strk;
>

Strk,

I decided to revert to GEOS-1.0.  Hiding CoordinateList helped,
but there were then problems with GeometryCollection ... and I
think I'll try to get it working with 1.0 first.  After a bit of
tweaking, I have a Python geos module that I can import.

* applied the change to PrecisionModel.cpp that you committed into
   the CVS head.
* directed SWIG to ignore declarations of 'throw_exception' because
   of an undefined symbol related to Geometry::throw_exception
* directed SWIG to ignore declarations of 'isClosed' because of an
   undefined symbol: _ZNK4geos10MultiPoint8isClosedEv

These last two changes leave the module in a less than fully
functional state, but I am encouraged.  Any idea what might be
the problem with Geometry::throw_exception and MultiPoint::isClosed?

thanks again,
Sean

Here's a "screenshot" for the curious:

Python 2.3.3 (#1, Jan  4 2004, 11:27:28)
[GCC 3.2.2 20030222 (Red Hat Linux 3.2.2-5)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
 >>> import geos
 >>> dir(geos)
['BasicCoordinateList', 'BasicCoordinateListFactory', 
'BasicCoordinateListFactoryPtr', 'BasicCoordinateListPtr', 
'Coordinate', 'CoordinateFilter', 'CoordinateFilterPtr', 
'CoordinateList', 'CoordinateListFactory', 'CoordinateListFactoryPtr', 
'CoordinateListPtr', 'CoordinateList_equals', 
'CoordinateList_hasRepeatedPoints', 'CoordinateList_indexOf', 
'CoordinateList_minCoordinate', 'CoordinateList_removeRepeatedPoints', 
'CoordinateList_reverse', 'CoordinateList_scroll', 'CoordinatePtr', 
'Dimension', 'DimensionPtr', 'Dimension_toDimensionSymbol', 
'Dimension_toDimensionValue', 'Envelope', 'EnvelopePtr', 
'GEOS_GEOMETRYCOLLECTION', 'GEOS_LINESTRING', 'GEOS_MULTILINESTRING', 
'GEOS_MULTIPOINT', 'GEOS_MULTIPOLYGON', 'GEOS_POINT', 'GEOS_POLYGON', 
'Geometry', 'GeometryCollection', 'GeometryCollectionIterator', 
'GeometryCollectionIteratorPtr', 'GeometryCollectionPtr', 
'GeometryComponentFilter', 'GeometryComponentFilterPtr', 
'GeometryFactory', 'GeometryFactoryPtr', 
'GeometryFactory_createPointFromInternalCoord', 
'GeometryFactory_toGeometry', 'GeometryFilter', 'GeometryFilterPtr', 
'GeometryPtr', 'IntersectionMatrix', 'IntersectionMatrixPtr', 
'LineSegment', 'LineSegmentPtr', 'LineString', 'LineStringPtr', 
'LinearRing', 'LinearRingPtr', 'Location', 'LocationPtr', 
'Location_toLocationSymbol', 'MultiLineString', 'MultiLineStringPtr', 
'MultiPoint', 'MultiPointPtr', 'MultiPolygon', 'MultiPolygonPtr', 
'Point', 'PointCoordinateList', 'PointCoordinateListFactory', 
'PointCoordinateListFactoryPtr', 'PointCoordinateListPtr', 'PointPtr', 
'Polygon', 'PolygonPtr', 'PrecisionModel', 'PrecisionModelPtr', 
'SFSCurve', 'SFSCurvePtr', 'SFSGeometry', 'SFSGeometryCollection', 
'SFSGeometryCollectionPtr', 'SFSGeometryPtr', 'SFSLineString', 
'SFSLineStringPtr', 'SFSLinearRing', 'SFSLinearRingPtr', 
'SFSMultiCurve', 'SFSMultiCurvePtr', 'SFSMultiLineString', 
'SFSMultiLineStringPtr', 'SFSMultiPoint', 'SFSMultiPointPtr', 
'SFSMultiPolygon', 'SFSMultiPolygonPtr', 'SFSMultiSurface', 
'SFSMultiSurfacePtr', 'SFSPoint', 'SFSPointPtr', 'SFSPolygon', 
'SFSPolygonPtr', 'SFSSurface', 'SFSSurfacePtr', '__builtins__', 
'__doc__', '__eq__', '__file__', '__name__', '_geos', 'cvar', 
'greaterThen', 'lessThen', 'point_3d', 'point_3dPtr']
 >>>