Use of a factory in a QTPlugin

[PeterPaulAndMary]

Hi,

I wanted to implement a factory method in my plugin interface for using more than one instance of the implemented plugin in my program afterwards.

So I have

virtual QObject *createInstance() = 0;

virtual QObject *createInstance() = 0;

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in the interface for my plugins.
And an example plugin implements this part like this:

QObject *TemplatePlugin::createInstance()
{
    return new TemplatePlugin();
}

QObject *TemplatePlugin::createInstance()
{
    return new TemplatePlugin();
}

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But this seems not to work even if I try to manually cast my class TemplatePlugin to QObject.
The result is allways:

plugininterface.h:19: undefined reference to `_imp___ZTV15PluginInterface'

Perhaps I'm doing it all wrong right now, but that's why I'm asking.

Thanks in advance!