[Qgis-developer] Compiling against geos-3.0.0rc4

[Tom Elwertowski]

Mike Leahy wrote:
> /home/sources/qgis_unstable/src/core/libqgis_core.so: undefined
> reference to `geos::geom::Coordinate::Coordinate(double, double, double)'
> /home/sources/qgis_unstable/src/core/libqgis_core.so: undefined
> reference to `geos::io::WKTReader::~WKTReader()'
> /home/sources/qgis_unstable/src/core/libqgis_core.so: undefined
> reference to `geos::io::WKTReader::WKTReader(geos::geom::GeometryFactory
> const*)'
> /home/sources/qgis_unstable/src/core/libqgis_core.so: undefined
> reference to `geos::geom::Coordinate::~Coordinate()'

There is a change between GEOS 3.0.0rc3 and rc4 that requires either an 
edit to GEOS or a new compile flag to QGIS in order to compile.

I made the following edit to rc4 in order to provide the missing 
routines to QGIS. Change line 30 of source/inlines.cpp from

#if defined(__MINGW32__) && !defined(DLL_EXPORT)

to

#if !defined(__MINGW32__) || defined(__MINGW32__) && !defined(DLL_EXPORT)


Some routines, including four that QGIS needs, can be defined either 
inline or linked from the GEOS library. If you define GEOS_INLINE for 
QGIS, the functions will be defined inline and you won't need external 
copies of these routines.

A MINGW user was getting doubly defined errors when using GEOS_INLINE 
and therefore submitted a patch which removes the library routines. The 
patch was probably intended for MINGW only but actually affects all 
platforms. I'm surprised no one else has noticed. Perhaps everyone is 
defining GEOS_INLINE.

Tom