What am I missing? Unresolved externals

[derick]

Found something:

After undefining XPAF_DLL_EXPORT the unresolved externals went away...

Is there a difference in Qt4? I think I read somewhere that the moc now understands macro expantions....

[wysota]

Does that class of yours inherit QObject?

[derick]

Yes they do.

When I build the DLL my classes are not exported. I even tried to export my classes with:

# define XPAF_DLL_EXPORT Q_DECL_EXPORT
and
# define XPAF_DLL_EXPORT __declspec(dllexport)

Anything that I should try with QT4?

[derick]

Does anybody have some sample classes exported in external DLLs? Please

My code compiles but I get an error as my DLL does not show the exported classes. Or do we need to load DEF files?

[wysota]

Check Qt4 sources

[derick]

Maybe a more specific hint .. I only found some specific macros for plugins.

[derick]

I even tried:

#include <QtCore/qglobal.h>
// Win 32 DLL export macros
#ifdef WIN32
# ifdef BUILD_DLL
//#  define XPAF_DLL_EXPORT  __declspec(dllexport)
#  define XPAF_DLL_EXPORT  Q_DECL_EXPORT
# else
#  define XPAF_DLL_EXPORT  // Empty
# endif
#endif // WIN32

#include <QtCore/qglobal.h>
// Win 32 DLL export macros
#ifdef WIN32
# ifdef BUILD_DLL
//#  define XPAF_DLL_EXPORT  __declspec(dllexport)
#  define XPAF_DLL_EXPORT  Q_DECL_EXPORT
# else
#  define XPAF_DLL_EXPORT  // Empty
# endif
#endif // WIN32

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[wysota]

Are you sure you pinpointed the problem correctly? It looks like your plugin can't resolve a symbol. I know it shouldn't even try to, but... It looks like an overall compiler issue not a Qt one. Try to build any plugin which needs an external dependency (for example one that needs a "foo()" function. When you succeed, you'll come back to Qt. Maybe you lack some compiler option?

[derick]

Hmmm... after using:

#include <QtCore/qglobal.h>
#  define XPAF_DLL_EXPORT  Q_DECL_EXPORT

#include <QtCore/qglobal.h>
#  define XPAF_DLL_EXPORT  Q_DECL_EXPORT

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And the rebuild of the whole planet... one DLL worked .... phew....
Now to sort out the other...
It still is the same unresolved symbols so I'll check some defines...

[derick]

Sigh ... still no joy...

When creating a 2nd DLL the imports of the 1st does not work:

ezGScreenInterface.obj : error LNK2001: unresolved external symbol "public: static struct QMetaObject const ezCrm::ezBase::staticMetaObject" (?staticMetaObject@ezBase@ezCrm@@2UQMetaObject@@B)

ezGScreenInterface.obj : error LNK2001: unresolved external symbol "public: static struct QMetaObject const ezCrm::ezBase::staticMetaObject" (?staticMetaObject@ezBase@ezCrm@@2UQMetaObject@@B)

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ezGScreenInterfac declated in 2nd DLL
ezBase declared in 1st DLL

Any idea why teh meta object does not get exported in the 1st DLL?

[jacek]

When creating a 2nd DLL the imports of the 1st does not work:

When you compile code that will use your DLL (not the DLL itself), you need __declspec(dllimport) (in the same place where __declspec(dllexport) was).

[Paul Drummond]

I sorry, I am having a problem very similar to this, but when reading this thread I keep thinking, shouldn't Qt be abstracting all this?

Where in the Qt documentation does it say I need to have "dllexport", "dllimport" declarations everywhere?