Fail to link if compiled as shared lib + inline with MinGW

[SpaceIm]

With MinGW on Windows, linker reports multiple definition of symbols when geos 3.8.0 is created as a shared lib and DISABLE_GEOS_INLINE is OFF.
There is no issue with others combination (shared lib + inline off, static with inline or not).

Click to expand log

[ 99%] Linking CXX shared library ..\bin\libgeos.dll
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x20): multiple definition of `geos::geom::LineSegment::~LineSegment()'
CMakeFiles\geos.dir/objects.a(MinimumDiameter.cpp.obj):MinimumDiameter.cpp:(.text$_ZN4geos4geom11LineSegmentD1Ev[_ZN4geos4geom11LineSegmentD1Ev]+0x0): first defined here
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x30): multiple definition of `geos::noding::BasicSegmentString::getCoordinate(unsigned long long) const'
CMakeFiles\geos.dir/objects.a(EdgeNodingValidator.cpp.obj):EdgeNodingValidator.cpp:(.text$_ZNK4geos6noding18BasicSegmentString13getCoordinateEy[_ZNK4geos6noding18BasicSegmentString13getCoordinateEy]+0x0): first defined here
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x40): multiple definition of `geos::noding::BasicSegmentString::getCoordinates() const'
CMakeFiles\geos.dir/objects.a(EdgeNodingValidator.cpp.obj):EdgeNodingValidator.cpp:(.text$_ZNK4geos6noding18BasicSegmentString14getCoordinatesEv[_ZNK4geos6noding18BasicSegmentString14getCoordinatesEv]+0x0): first defined here
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x50): multiple definition of `geos::geom::LineSegment::~LineSegment()'
CMakeFiles\geos.dir/objects.a(MinimumDiameter.cpp.obj):MinimumDiameter.cpp:(.text$_ZN4geos4geom11LineSegmentD0Ev[_ZN4geos4geom11LineSegmentD0Ev]+0x0): first defined here
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x60): multiple definition of `geos::geom::CoordinateArraySequenceFactory::create() const'
CMakeFiles\geos.dir/objects.a(CoordinateArraySequenceFactory.cpp.obj):CoordinateArraySequenceFactory.cpp:(.text$_ZNK4geos4geom30CoordinateArraySequenceFactory6createEv[_ZNK4geos4geom30CoordinateArraySequenceFactory6createEv]+0x0): first defined here
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0xb0): multiple definition of `geos::geom::CoordinateArraySequenceFactory::create(std::vector<geos::geom::Coordinate, std::allocator<geos::geom::Coordinate> >*, unsigned long long) const'
CMakeFiles\geos.dir/objects.a(CoordinateArraySequenceFactory.cpp.obj):CoordinateArraySequenceFactory.cpp:(.text$_ZNK4geos4geom30CoordinateArraySequenceFactory6createEPSt6vectorINS0_10CoordinateESaIS3_EEy[_ZNK4geos4geom30CoordinateArraySequenceFactory6createEPSt6vectorINS0_10CoordinateESaIS3_EEy]+0x0): first defined here
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x100): multiple definition of `geos::geom::CoordinateArraySequenceFactory::create(std::vector<geos::geom::Coordinate, std::allocator<geos::geom::Coordinate> >&&, unsigned long long) const'
CMakeFiles\geos.dir/objects.a(CoordinateArraySequenceFactory.cpp.obj):CoordinateArraySequenceFactory.cpp:(.text$_ZNK4geos4geom30CoordinateArraySequenceFactory6createEOSt6vectorINS0_10CoordinateESaIS3_EEy[_ZNK4geos4geom30CoordinateArraySequenceFactory6createEOSt6vectorINS0_10CoordinateESaIS3_EEy]+0x0): first defined here
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x150): multiple definition of `geos::geom::CoordinateArraySequenceFactory::create(unsigned long long, unsigned long long) const'
CMakeFiles\geos.dir/objects.a(CoordinateArraySequenceFactory.cpp.obj):CoordinateArraySequenceFactory.cpp:(.text$_ZNK4geos4geom30CoordinateArraySequenceFactory6createEyy[_ZNK4geos4geom30CoordinateArraySequenceFactory6createEyy]+0x0): first defined here
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x1a0): multiple definition of `geos::geom::CoordinateArraySequenceFactory::create(geos::geom::CoordinateSequence const&) const'
CMakeFiles\geos.dir/objects.a(CoordinateArraySequenceFactory.cpp.obj):CoordinateArraySequenceFactory.cpp:(.text$_ZNK4geos4geom30CoordinateArraySequenceFactory6createERKNS0_18CoordinateSequenceE[_ZNK4geos4geom30CoordinateArraySequenceFactory6createERKNS0_18CoordinateSequenceE]+0x0): first defined here
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x200): multiple definition of `geos::noding::BasicSegmentString::isClosed() const'
CMakeFiles\geos.dir/objects.a(EdgeNodingValidator.cpp.obj):EdgeNodingValidator.cpp:(.text$_ZNK4geos6noding18BasicSegmentString8isClosedEv[_ZNK4geos6noding18BasicSegmentString8isClosedEv]+0x0): first defined here
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x1b90): multiple definition of `geos::geom::MultiLineString::clone() const'
CMakeFiles\geos.dir/objects.a(MultiLineString.cpp.obj):MultiLineString.cpp:(.text$_ZNK4geos4geom15MultiLineString5cloneEv[_ZNK4geos4geom15MultiLineString5cloneEv]+0x0): first defined here
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x1c20): multiple definition of `geos::geom::MultiPolygon::clone() const'
CMakeFiles\geos.dir/objects.a(MultiPolygon.cpp.obj):MultiPolygon.cpp:(.text$_ZNK4geos4geom12MultiPolygon5cloneEv[_ZNK4geos4geom12MultiPolygon5cloneEv]+0x0): first defined here
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x2330): multiple definition of `geos::geomgraph::Quadrant::quadrant(double, double)'
CMakeFiles\geos.dir/objects.a(EdgeEnd.cpp.obj):EdgeEnd.cpp:(.text$_ZN4geos9geomgraph8Quadrant8quadrantEdd[_ZN4geos9geomgraph8Quadrant8quadrantEdd]+0x0): first defined here
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x2a50): multiple definition of `geos::geomgraph::GeometryGraph::~GeometryGraph()'
CMakeFiles\geos.dir/objects.a(PointLocator.cpp.obj):PointLocator.cpp:(.text$_ZN4geos9geomgraph13GeometryGraphD1Ev[_ZN4geos9geomgraph13GeometryGraphD1Ev]+0x0): first defined here
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x2af0): multiple definition of `geos::geomgraph::GeometryGraph::~GeometryGraph()'
CMakeFiles\geos.dir/objects.a(PointLocator.cpp.obj):PointLocator.cpp:(.text$_ZN4geos9geomgraph13GeometryGraphD0Ev[_ZN4geos9geomgraph13GeometryGraphD0Ev]+0x0): first defined here
CMakeFiles\geos.dir/objects.a(MCIndexNoder.cpp.obj):MCIndexNoder.cpp:(.text$_ZNK4geos6noding12MCIndexNoder18getNodedSubstringsEv[_ZNK4geos6noding12MCIndexNoder18getNodedSubstringsEv]+0x0): multiple definition of `geos::noding::MCIndexNoder::getNodedSubstrings() const'
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x2a40): first defined here
CMakeFiles\geos.dir/objects.a(MaximalEdgeRing.cpp.obj):MaximalEdgeRing.cpp:(.text$_ZN4geos9operation7overlay15MinimalEdgeRing11setEdgeRingEPNS_9geomgraph12DirectedEdgeEPNS3_8EdgeRingE[_ZN4geos9operation7overlay15MinimalEdgeRing11setEdgeRingEPNS_9geomgraph12DirectedEdgeEPNS3_8EdgeRingE]+0x0): multiple definition of `geos::operation::overlay::MinimalEdgeRing::setEdgeRing(geos::geomgraph::DirectedEdge*, geos::geomgraph::EdgeRing*)'
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x0): first defined here
CMakeFiles\geos.dir/objects.a(MaximalEdgeRing.cpp.obj):MaximalEdgeRing.cpp:(.text$_ZN4geos9operation7overlay15MinimalEdgeRing7getNextEPNS_9geomgraph12DirectedEdgeE[_ZN4geos9operation7overlay15MinimalEdgeRing7getNextEPNS_9geomgraph12DirectedEdgeE]+0x0): multiple definition of `geos::operation::overlay::MinimalEdgeRing::getNext(geos::geomgraph::DirectedEdge*)'
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x10): first defined here
CMakeFiles\geos.dir/objects.a(MaximalEdgeRing.cpp.obj):MaximalEdgeRing.cpp:(.text$_ZN4geos9operation7overlay15MinimalEdgeRingD1Ev[_ZN4geos9operation7overlay15MinimalEdgeRingD1Ev]+0x0): multiple definition of `geos::operation::overlay::MinimalEdgeRing::~MinimalEdgeRing()'
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x680): first defined here
CMakeFiles\geos.dir/objects.a(MaximalEdgeRing.cpp.obj):MaximalEdgeRing.cpp:(.text$_ZN4geos9operation7overlay15MinimalEdgeRingD0Ev[_ZN4geos9operation7overlay15MinimalEdgeRingD0Ev]+0x0): multiple definition of `geos::operation::overlay::MinimalEdgeRing::~MinimalEdgeRing()'
CMakeFiles\geos.dir/objects.a(inlines.cpp.obj):inlines.cpp:(.text+0x820): first defined here
collect2.exe: error: ld returned 1 exit status

Quick fix:

--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -224,7 +224,7 @@ add_subdirectory(src)

 if(BUILD_SHARED_LIBS)
   target_compile_definitions(geos
-    PRIVATE $<$<CXX_COMPILER_ID:MSVC>:GEOS_DLL_EXPORT>)
+    PRIVATE $<IF:$<CXX_COMPILER_ID:MSVC>,GEOS_DLL_EXPORT,DLL_EXPORT>)

   set_target_properties(geos PROPERTIES VERSION ${GEOS_VERSION})
   set_target_properties(geos PROPERTIES SOVERSION ${GEOS_VERSION})
@@ -238,7 +238,7 @@ target_link_libraries(geos_c PRIVATE geos)

 if(BUILD_SHARED_LIBS)
   target_compile_definitions(geos_c
-    PRIVATE $<$<CXX_COMPILER_ID:MSVC>:GEOS_DLL_EXPORT>)
+    PRIVATE $<IF:$<CXX_COMPILER_ID:MSVC>,GEOS_DLL_EXPORT,DLL_EXPORT>)

   set_target_properties(geos_c PROPERTIES VERSION ${CAPI_VERSION})
   if(NOT WIN32)

Therefore, inline.cpp is not compiled if MinGW + shared + inline (and we can make use of DLL_EXPORT which is not used or defined anywhere else in source code):

...
// Only do something if GEOS_INLINE is defined
// Otherwise we'll end up with duplicated symbols
#ifdef GEOS_INLINE

// If using Visual C++ with GEOS_INLINE, do not build inline.obj
// otherwise linker will complain "multiple definition" errors.
// If using MingW with GEOS_INLINE to build a DLL then MingW's gcc
// has already generated the stubs for the contents of this file.
// Hence we need to suppress it to avoid "multiple definition" errors
// during the final link phase
#if !defined(_MSC_VER) && (!defined(__MINGW32__) || defined(__MINGW32__) && !defined(GEOS_DLL_EXPORT) && !defined(DLL_EXPORT) )
...

[dbaston]

@robe2 could you test this fix on your system, please?

[robe2]

@dbaston okay will do and will report back

[robe2]

Okay works on my mingw system. @SpaceIm can you provide this as a pull request so we can give you credit for it.

[SpaceIm]

Sure, done ;)