[compile error] Fix openNURBS compile issue under Windows

[SunBlack]

Currently you are getting following compile issue under windows in case you have BUILD_surface_on_nurbs enabled:

example_nurbs_viewer_surface.obj : error LNK2019: unresolved external symbol ON_ErrorEx referenced in function "public: class ONX_Model_Object & __cdecl ON_ClassArray<class ONX_Model_Object>::operator[](int)" (??A?$ON_ClassArray@VONX_Model_Object@@@@QEAAAEAVONX_Model_Object@@H@Z)
35>

Reason is the missing macro ON_DLL_TEMPLATE, caused by missing macro ON_DLL_EXPORTS

pcl/surface/include/pcl/surface/3rdparty/opennurbs/opennurbs_extensions.h

Lines 139 to 167 in 8eb4768

	#if defined(ON_DLL_TEMPLATE)
	// This stuff is here because of a limitation in the way Microsoft
	// handles templates and DLLs. See Microsoft's knowledge base
	// article ID Q168958 for details.
	#pragma warning( push )
	#pragma warning( disable : 4231 )
	ON_DLL_TEMPLATE template class ON_CLASS ON_SimpleArray<ON_Bitmap*>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_ClassArray<ON_Linetype>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_ObjectArray<ON_Linetype>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_ClassArray<ON_Layer>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_ObjectArray<ON_Layer>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_ClassArray<ON_Group>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_ObjectArray<ON_Group>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_ClassArray<ON_Font>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_ObjectArray<ON_Font>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_ClassArray<ON_DimStyle>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_ObjectArray<ON_DimStyle>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_ClassArray<ONX_Model_RenderLight>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_ClassArray<ON_HatchPattern>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_ObjectArray<ON_HatchPattern>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_ClassArray<ON_InstanceDefinition>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_ObjectArray<ON_InstanceDefinition>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_ClassArray<ONX_Model_Object>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_ClassArray<ONX_Model_UserData>;
	ON_DLL_TEMPLATE template class ON_CLASS ON_SimpleArray<ON_HistoryRecord*>;
	#pragma warning( pop )
	#endif

The macro will be defined here:

pcl/surface/include/pcl/surface/3rdparty/opennurbs/opennurbs_defines.h

Lines 88 to 123 in c440618

	#if defined(ON_DLL_EXPORTS)
	#if !defined(ON_COMPILING_OPENNURBS)
	#error When compiling an OpenNURBS DLL, ON_DLL_EXPORTS must be defined
	#endif
	/* compiling OpenNurbs as a Windows DLL - export classes, functions, templates, and globals */
	#define ON_CLASS __declspec(dllexport)
	#define ON_DECL __declspec(dllexport)
	#define ON_EXTERN_DECL __declspec(dllexport)
	#define ON_DLL_TEMPLATE
	#elif defined(ON_DLL_IMPORTS)
	#if defined(ON_COMPILING_OPENNURBS)
	#error When compiling an OpenNURBS DLL, ON_DLL_IMPORTS must NOT be defined
	#endif
	/* using OpenNurbs as a Windows DLL - import classes, functions, templates, and globals */
	#define ON_CLASS __declspec(dllimport)
	#define ON_DECL __declspec(dllimport)
	#define ON_EXTERN_DECL __declspec(dllimport)
	#define ON_DLL_TEMPLATE extern
	#else
	/* compiling or using OpenNurbs as a static library */
	#define ON_CLASS
	#define ON_DECL
	#define ON_EXTERN_DECL
	#if defined(ON_DLL_TEMPLATE)
	#undef ON_DLL_TEMPLATE
	#endif
	#endif

To enable this block OPENNURBS_EXPORTS needs to be defined

pcl/surface/include/pcl/surface/3rdparty/opennurbs/opennurbs_defines.h

Lines 66 to 70 in c440618

	#if defined(OPENNURBS_EXPORTS)
	// OPENNURBS_EXPORTS is Microsoft's prefered defined for building an opennurbs DLL.
	#if !defined(ON_DLL_EXPORTS)
	#define ON_DLL_EXPORTS
	#endif

And surprise: OPENNURBS_EXPORTS will be never be defined.

A long time ago there was already a try to fix issues with it, but this fix was incomplete.

So we have the choice:

• Adding OPENNURBS_EXPORTS flag: In this case we need to export OPENNURBS_IMPORTS, too and revert the old fix. Otherwise you are getting tons of warnings: warning C4141: 'dllexport': used more than once (compiling source file C:\dev\pcl\surface\src\3rdparty\opennurbs\opennurbs_3dm_attributes.cpp)
• Replacing ON_CLASS and all other openNURBS specific macros by e.g. PCL_EXPORTS. In this case we have currently no replacement for e.g. ON_DLL_TEMPLATE

[larshg]

Which VTK version do you use?

For some reason I can't reproduce right now with the VTK9 branch I'm working on.

Though I'm not sure if it is related...

[SunBlack]

Do you have BUILD_surface_on_nurbs enabled? (I'm using VTK 8.2)

[larshg]

Yes. And the example can build and run:

[larshg]

I did see this error before locally. But the only change since then is the vtk 8.2 -> vtk 9.

[SunBlack]

Mhm interesting. Can you try it again with VTK 8.2?

[larshg]

Did you build in debug? I did release.

You mention in this old PR #3140 (comment)

That it happens in debug ?

[SunBlack]

Ah yes, Debug build

[larshg]

pcl/surface/include/pcl/surface/3rdparty/opennurbs/opennurbs_error.h

Lines 47 to 53 in c440618

	ON_DECL
	void ON_ErrorMessage(
	int, /* 0 = warning message, 1 = serious error message, 2 = assert failure */
	const char*
	);
	/*

Think we need to add either PCL_EXPORT to this.

OR add the two defines:

ON_DLL_EXPORTS
ON_COMPILING_OPENNURBS

However, it now complained about linking to:
./x64/debug/zlib.lib

Needs a bit more digging :D

[SunBlack]

Same here with ./x64/debug/zlib.lib 😢 Until now I don't have an idea why MSVC is trying to link against it.

[larshg]

Its happening in this file by pragmas:
https://github.com/PointCloudLibrary/pcl/blob/cc7fe363c6463a0abc617b1e17e94ab4bd4169ef/surface/include/pcl/surface/3rdparty/opennurbs/examples_linking_pragmas.h

Probably easier to add the PCL_EXPORT in front of all the debug functions.

[larshg]

Maybe its here rather:
https://github.com/PointCloudLibrary/pcl/blob/8d5fa69f0afde84e153df6e2321ea5165b12d59c/surface/src/3rdparty/opennurbs/opennurbs_zlib.cpp