Linker errors from inherited virtual functions, help!

stooo (4)
Hi all. I've done my best to research this myself but I've got some linker errors I just can't get rid of, all related to inherited virtual functions. I'm trying to override two virtual functions, open() and close(), from the VST3 SDK. I think all relevant code is below, class declarations are from different files but linked with appropriate #include directives. Any help appreciated, thanks very much.

Base class - from VSTGUIEditor.h
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class VSTGUIEditor : public EditorView, public VSTGUIEditorInterface, public CBaseObject
{
public:
	/** Constructor. */
	VSTGUIEditor (void* controller, ViewRect* size = 0);
	
	/** Destructor. */
	~VSTGUIEditor ();

	//---Internal function-----
	/** Called when the editor will be opened. */
	virtual bool PLUGIN_API open (void* parent) = 0;
	/** Called when the editor will be closed. */
	virtual void PLUGIN_API close () = 0;

	/** Sets the idle rate controlling the parameter update rate. */
	void setIdleRate (int32 millisec);

	//---from CBaseObject---------------
	CMessageResult notify (CBaseObject* sender, const char* message);
	void forget () { EditorView::release (); }
	void remember () { EditorView::addRef (); }
	VSTGUI_INT32 getNbReference () const { return refCount; }

	//---from IPlugView-------
	tresult PLUGIN_API isPlatformTypeSupported (FIDString type);
	tresult PLUGIN_API onSize (ViewRect* newSize);

	//---from VSTGUIEditorInterface-------
	/** Called from VSTGUI when a user begins editing. 
		The default implementation calls performEdit of the EditController. */
	void beginEdit (VSTGUI_INT32 index);
	/** Called from VSTGUI when a user ends editing. 
		The default implementation calls endEdit of the EditController. */
	void endEdit (VSTGUI_INT32 index);

	VSTGUI_INT32 getKnobMode () const;
private:
	//---from IPlugView-------
	tresult PLUGIN_API attached (void* parent, FIDString type);
	tresult PLUGIN_API removed ();
	tresult PLUGIN_API onKeyDown (char16 key, int16 keyMsg, int16 modifiers);
	tresult PLUGIN_API onKeyUp (char16 key, int16 keyMsg, int16 modifiers);
	tresult PLUGIN_API onWheel (float distance);

	CVSTGUITimer* timer;
};


Derived class - from vst3call.cpp. Calling VSTGUIEditor constructor.
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class myclass : 	public VSTGUIEditor
{
public:
//------------------------------------------------------------------------

	myclass  (void* controller, ViewRect* size)
		: VSTGUIEditor (controller, size)
	{}

	 bool PLUGIN_API open (void* parent);
	 void PLUGIN_API close ();
};


Creating instance of inherited class - from vst3call.cpp

 
 
	myclass testinstance (&objs,&err);

Where parameters &objs and &err are (I think)correctly initialised for the VSTGUIEditor constructor.

And to the linker errors:


Error	21	error LNK2019: unresolved external symbol "public: __thiscall Steinberg::Vst::VSTGUIEditor::VSTGUIEditor(void *,struct Steinberg::ViewRect *)" (??0VSTGUIEditor@Vst@Steinberg@@QAE@PAXPAUViewRect@2@@Z) referenced in function "public: __thiscall Steinberg::Vst::myclass::myclass(void *,struct Steinberg::ViewRect *)" (??0myclass@Vst@Steinberg@@QAE@PAXPAUViewRect@2@@Z)	C:\...\VST3 GUI take3\vst3_call.obj
Error	22	error LNK2001: unresolved external symbol "public: virtual void __thiscall Steinberg::Vst::EditorView::attachedToParent(void)" (?attachedToParent@EditorView@Vst@Steinberg@@UAEXXZ)	C:\...\VST3 GUI take3\vst3_call.obj
Error	23	error LNK2001: unresolved external symbol "public: virtual void __thiscall Steinberg::Vst::EditorView::removedFromParent(void)" (?removedFromParent@EditorView@Vst@Steinberg@@UAEXXZ)	C:\...\VST3 GUI take3\vst3_call.obj
Error	24	error LNK2001: unresolved external symbol "public: virtual bool __stdcall Steinberg::Vst::myclass::open(void *)" (?open@myclass@Vst@Steinberg@@UAG_NPAX@Z)	C:\...\VST3 GUI take3\vst3_call.obj
Error	25	error LNK2001: unresolved external symbol "public: virtual void __stdcall Steinberg::Vst::myclass::close(void)" (?close@myclass@Vst@Steinberg@@UAGXXZ)	C:\...\VST3 GUI take3\vst3_call.obj
Error	26	error LNK2001: unresolved external symbol "public: virtual long __stdcall Steinberg::Vst::VSTGUIEditor::isPlatformTypeSupported(char const *)" (?isPlatformTypeSupported@VSTGUIEditor@Vst@Steinberg@@UAGJPBD@Z)	C:\...\VST3 GUI take3\vst3_call.obj
Error	27	error LNK2001: unresolved external symbol "private: virtual long __stdcall Steinberg::Vst::VSTGUIEditor::attached(void *,char const *)" (?attached@VSTGUIEditor@Vst@Steinberg@@EAGJPAXPBD@Z)	C:\...\VST3 GUI take3\vst3_call.obj
Error	28	error LNK2001: unresolved external symbol "private: virtual long __stdcall Steinberg::Vst::VSTGUIEditor::removed(void)" (?removed@VSTGUIEditor@Vst@Steinberg@@EAGJXZ)	C:\...\VST3 GUI take3\vst3_call.obj
Error	29	error LNK2001: unresolved external symbol "private: virtual long __stdcall Steinberg::Vst::VSTGUIEditor::onWheel(float)" (?onWheel@VSTGUIEditor@Vst@Steinberg@@EAGJM@Z)	C:\...\VST3 GUI take3\vst3_call.obj
Error	30	error LNK2001: unresolved external symbol "private: virtual long __stdcall Steinberg::Vst::VSTGUIEditor::onKeyDown(wchar_t,short,short)" (?onKeyDown@VSTGUIEditor@Vst@Steinberg@@EAGJ_WFF@Z)	C:\...\VST3 GUI take3\vst3_call.obj
Error	31	error LNK2001: unresolved external symbol "private: virtual long __stdcall Steinberg::Vst::VSTGUIEditor::onKeyUp(wchar_t,short,short)" (?onKeyUp@VSTGUIEditor@Vst@Steinberg@@EAGJ_WFF@Z)	C:\...\VST3 GUI take3\vst3_call.obj
Error	32	error LNK2001: unresolved external symbol "public: virtual long __stdcall Steinberg::CPluginView::getSize(struct Steinberg::ViewRect *)" (?getSize@CPluginView@Steinberg@@UAGJPAUViewRect@2@@Z)	C:\...\VST3 GUI take3\vst3_call.obj
Error	33	error LNK2001: unresolved external symbol "public: virtual long __stdcall Steinberg::Vst::VSTGUIEditor::onSize(struct Steinberg::ViewRect *)" (?onSize@VSTGUIEditor@Vst@Steinberg@@UAGJPAUViewRect@3@@Z)	C:\...\VST3 GUI take3\vst3_call.obj
Error	34	error LNK2001: unresolved external symbol "public: virtual long __thiscall Steinberg::Vst::VSTGUIEditor::getKnobMode(void)const " (?getKnobMode@VSTGUIEditor@Vst@Steinberg@@UBEJXZ)	C:\...\VST3 GUI take3\vst3_call.obj
Error	35	error LNK2001: unresolved external symbol "public: virtual void __thiscall Steinberg::Vst::VSTGUIEditor::beginEdit(long)" (?beginEdit@VSTGUIEditor@Vst@Steinberg@@UAEXJ@Z)	C:\...\VST3 GUI take3\vst3_call.obj
Error	36	error LNK2001: unresolved external symbol "public: virtual void __thiscall Steinberg::Vst::VSTGUIEditor::endEdit(long)" (?endEdit@VSTGUIEditor@Vst@Steinberg@@UAEXJ@Z)	C:\...\VST3 GUI take3\vst3_call.obj
Error	37	error LNK2001: unresolved external symbol "public: virtual enum VSTGUI::CMessageResult __thiscall Steinberg::Vst::VSTGUIEditor::notify(class VSTGUI::CBaseObject *,char const *)" (?notify@VSTGUIEditor@Vst@Steinberg@@UAE?AW4CMessageResult@VSTGUI@@PAVCBaseObject@5@PBD@Z)	C:\...\VST3 GUI take3\vst3_call.obj
Error	38	error LNK2019: unresolved external symbol "public: virtual __thiscall Steinberg::Vst::VSTGUIEditor::~VSTGUIEditor(void)" (??1VSTGUIEditor@Vst@Steinberg@@UAE@XZ) referenced in function "public: virtual __thiscall Steinberg::Vst::myclass::~myclass(void)" (??1myclass@Vst@Steinberg@@UAE@XZ)	C:\...\VST3 GUI take3\vst3_call.obj
Error	39	error LNK1120: 18 unresolved externals	C:\...\VST3 GUI take3.exe

Last edited on
mmay (55)
Are you sure the VST3 link library has been included in the linker line/properties?
stooo (4)
Thanks for the reply, yeah the base dll is included in the linker properties. Sorry I should have mentioned that elsewhere in the code I call other functions from the SDK without issue.
mmay (55)
Are there multiple VST3 libraries involved? ... I notice that the notify() / forget() / remember() / getNbReference() methods seem to be being resolved okay (or they aren't ever invoked)... *thinking out aloud* also wondering if your PLUGIN_API symbol is being defined correctly, but the beginEdit() / endEdit() routines aren't found either (there may be different name mangling if PLUGIN_API was not defined appropriately). Hmmmm...

If it was me, I'd probably check the VST3 .lib files to see what entrypoints _are_ defined (looking specifically for the ones you're missing, of course). The errors seem to be pointing toward a missing library (or incorrect compile) somewhere along the line... v(-_-)v. You are using the correct compiler for the link libraries I hope?
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stooo (4)
Many thanks for your suggestions. There's just the one VST3 library, and I'm using Visual Studio 2010 to compile.

My original assumption was that there was a fault with my method of inheriting/overriding virtual functions - I have a lot of gaps in my c++ knowledge - but if my method is correct I'll be looking further at the .lib definitions as suggested. :) Any other ideas anybody?
mmay (55)
Sorry, me again <(^_^)...

... out of curiosity, is the namespace "Steinberg" (and the nested namespace "Vst") something you've added, or are they present within VSTGUIEditor.h?

(just wondering if you might have wrapped the #includes within a namespace Steinberg, which might result in the observed missing symbols...)
stooo (4)
Haha thanks again mmay.

The Steinberg/Vst namespaces are part of the SDK, and so yes are present within VSTGUIEditor.h. It's a good thought, I had temporarily forgotten the namespaces were there :), but sadly no there doesn't appear to be any problems with wrapping #includes within the namespace definitions...
mmay (55)
Are there any sample programs provided with the SDK (that use that class)? ... do those link in your working environment? That would help to disprove any mismatch between your compiler or linker or 32 vs 64-bit or settings or library version etc.

If you #ifdef out that class... does the rest of the code link?

I do know how annoying it is to have a nice shiny SDK that just Doesn't Seem To Work... but I'm running out of ideas here (>_<).
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