QMap value type with virtual destructor

[Vikram.Saralaya]

Hello,

I solved a problem that troubled me for a while and now I am interested in getting more insight into what has been happening here..

I have a custom data type that I want to store as a value in QMap.

QMap<uint, CustomType>

QMap<uint, CustomType>

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My CustomType looks like:

class CustomType
{
public:
    CustomType() { m_objectRef = nullptr; m_slotName = nullptr; }
    CustomType(QObject* obj, const char* slotName) { m_objectRef = obj; m_slotName = slotName; }
    virtual ~CustomType() {}
 
    // Accessors
    QObject*                GetObjectName() { return m_objectRef; }
    const char*             GetSlotName()   { return m_slotName; }
 
private:
    QObject*                m_objectRef;
    const char*             m_slotName;
};

class CustomType
{
public:
    CustomType() { m_objectRef = nullptr; m_slotName = nullptr; }
    CustomType(QObject* obj, const char* slotName) { m_objectRef = obj; m_slotName = slotName; }
    virtual ~CustomType() {}

    // Accessors
    QObject*                GetObjectName() { return m_objectRef; }
    const char*             GetSlotName()   { return m_slotName; }

private:
    QObject*                m_objectRef;
    const char*             m_slotName;
};

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I get a compilation error saying:

undefined reference to `_imp___ZTV10CustomType'

undefined reference to `_imp___ZTV10CustomType'

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Solution:
Remove virtual keyword from the destructor.

My question:
Why can't I have a virtual destructor here?

Thank you!

Regards
Vikram