Qt statically linked to a library -> symbol(s) not found for architecture x86_64

[hitme]

hey,

i'm trying to implement a static library that uses qt.
so far, i am able to build qt sources statically and link them to my library. as soon as i try to include the library to a main application i get several

bq. Undefined symbols for architecture x86_64:
"vtable for NI::NT::ScriptApi::Fields", referenced from:
ScriptApi::Fields::Fields() in libNTFramework.a(Fields.o)
ScriptApi::Fields::~Fields() in libNTFramework.a(Fields.o)
NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
(...)
ld: symbol(s) not found for architecture x86_64

errors. when using qt built dynamically the errors do not occur.
checking my library by using

@lipo -info libNTFramework.a@

output tells me that everything is built fine for the x86_64 arch:

bq. Architectures in the fat file: (...)/libNTFramework.a are: x86_64 i386

Fields.h:
@class Fields : public QObject
{
Q_OBJECT
friend class ComponentManager;

public:
QScriptValue scriptValue() const;

public slots:
void bind(const QString name, QScriptValue control);
void set(const QString name, const QVariant value);
QVariant get(const QString name) const;

private:
Fields();
virtual ~Fields();

QScriptValue m_scriptValue;
ComponentManager* const componentManager() const;

};@

Fields.cpp:
@Fields::Fields()
{
}

Fields::~Fields()
{
}

QScriptValue Fields::scriptValue() const
{
return m_scriptValue;
}

(...)@

update:

ComponentManager.cpp
@ComponentManager::ComponentManager(QScriptEngine* const engine,
ScriptableWizard* const wizard,
Application* const application) :
m_application(application),
m_scriptEngine(engine),
m_scriptableWizard(wizard)
{
s_instance = this;
m_scriptApiFields = new ScriptApi::Fields();
(...)
}

//! Delete the ComponentManager and all singletons created by it.
ComponentManager::~ComponentManager()
{
delete m_scriptApiFields;
(...)
}
(...)@

any ideas what i am missing?
thx in advance!

[hitme]

mmh, noone? still struggeling with this... suggestions appreciated...

[hitme]

is the the problem description too poor? or noone any experience with this? would be great if someone could lead me into the right direction...

[koahnig]

welcome to devnet

Why is your constructor and your destructor private?
Typically those are public. You want make a special constructor private, if you want to exclude it from use. But there is no other one. I am not sure, if the destructor may be private at all.

[hitme]

hi and thx for the welcome... "fields" is a singleton object that is created and managed in the friend class "componentmanager". i declared it private to make sure it is only created once/in the one friend class.

[koahnig]

I have no experience with singleton objects, but I am wondering how you are constructing a Fields object and how you want to destruct. You need to have a constructor even when managed in a friend class. At least in C++.

[hitme]

there is a constructor and the object is created/deleted the common way (see my initial post, i added some lines of ComponentManager.cpp). when using a library that contains the dynamically linked qt sources all goes fine, the application can be compiled/linked and executed.