I'm trying to use a DLL which consists of one UI which I have subclassed. (I'm using Qt3 and Visual Studio .NET 2003) The UI is called MyMainWindowBase.ui which results in MyMainWindowBase.h and MyMainWindowBase.cpp when uic'ed. Then I subclass this in my own class called MyMainWindow. MyMainWindow includes my own DLL_EXPORT macro. But when I create a DLL and try to link this with some other code I get a lot of unresolved externals from MyMainWindowBase. I guess this is because the symbols in that class are not exported, because if I remove the DLL_EXPORT macro from MyMainWindow I get a lot of unresolved externals from that too. How can I get the symbols from the base class exported, or is there something else I'm missing?

Myinterface.obj : error LNK2001: unresolved external symbol "protected: virtual void __thiscall MyMainWindowBase::languageChange(void)" (?languageChange@MyMainWindowBase@@MAEXXZ)
Myinterface.obj : error LNK2019: unresolved external symbol "public: virtual __thiscall MyMainWindowBase::~MyMainWindowBase(void)" (??1MyMainWindowBase@@UAE@XZ) referenced in function $L32824
Myinterface.obj : error LNK2001: unresolved external symbol "public: virtual bool __thiscall MyMainWindowBase::qt_property(int,int,class QVariant *)" (?qt_property@MyMainWindowBase@@UAE_NHHPAVQVariant @@@Z)
Myinterface.obj : error LNK2001: unresolved external symbol "public: virtual bool __thiscall MyMainWindowBase::qt_emit(int,struct QUObject *)" (?qt_emit@MyMainWindowBase@@UAE_NHPAUQUObject@@@Z)
Myinterface.obj : error LNK2001: unresolved external symbol "public: virtual bool __thiscall MyMainWindowBase::qt_invoke(int,struct QUObject *)" (?qt_invoke@MyMainWindowBase@@UAE_NHPAUQUObject@@@ Z)
Myinterface.obj : error LNK2001: unresolved external symbol "public: virtual void * __thiscall MyMainWindowBase::qt_cast(char const *)" (?qt_cast@MyMainWindowBase@@UAEPAXPBD@Z)
Myinterface.obj : error LNK2001: unresolved external symbol "public: virtual char const * __thiscall MyMainWindowBase::className(void)const " (?className@MyMainWindowBase@@UBEPBDXZ)
Myinterface.obj : error LNK2019: unresolved external symbol "public: static class QMetaObject * __cdecl MyMainWindowBase::staticMetaObject(void)" (?staticMetaObject@MyMainWindowBase@@SAPAVQMetaObj ect@@XZ) referenced in function "public: virtual class QMetaObject * __thiscall MyMainWindowBase::metaObject(void)const " (?metaObject@MyMainWindowBase@@UBEPAVQMetaObject@@ XZ)
..\lib\debug\win32\Mymainwindow.dll : fatal error LNK1120: 8 unresolved externals