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Thread: undefined symbol while loading plugin

  1. #1
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    Unhappy undefined symbol while loading plugin

    Hi,

    I have a plugin library (like the QT plug-and-paint example) that contains a series of QWidgets to enter data.

    The interface of the plugin has a pure virtual fuction called QWidget* impMainModules::loadScreen(QString pluginName) that returns a widget bases on a plugin name.

    All worked fine until I wanted to create a QtableModel to use in some of the widgets:
    Qt Code:
    1. class fieldInRowModel : public QAbstractTableModel
    2. {
    3. Q_OBJECT
    4. public:
    5. fieldInRowModel(QObject *parent=0);
    6. ~fieldInRowModel();
    7.  
    8. int rowCount(const QModelIndex & parent = QModelIndex()) const;
    9. int columnCount(const QModelIndex &parent = QModelIndex()) const;
    10. QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const;
    11. void setDatabase (QSqlDatabase db);
    12. private:
    13. QSqlDatabase database;
    14.  
    15. };
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    Implemented as:
    Qt Code:
    1. fieldInRowModel::fieldInRowModel(QObject *parent)
    2. {
    3.  
    4. }
    5.  
    6. fieldInRowModel::~fieldInRowModel()
    7. {
    8.  
    9. }
    10.  
    11. int fieldInRowModel::rowCount(const QModelIndex &) const
    12. {
    13. return 0; //Test value
    14. }
    15.  
    16. int fieldInRowModel::columnCount(const QModelIndex &) const
    17. {
    18. return 0; //Test value
    19. }
    20. QVariant fieldInRowModel::data(const QModelIndex &/*index*/, int /*role*/) const
    21. {
    22. return QVariant(); //Test value
    23. }
    24. void fieldInRowModel::setDatabase (QSqlDatabase db)
    25. {
    26. database = db;
    27. }
    To copy to clipboard, switch view to plain text mode 

    fieldInRowModel is in a separate file called moduleclasses.h and cpp that are part of the plugin library project .

    Now, with the inclusion of this class in the plugin library, I get the following error when the main application intents to load the plugin.
    Qt Code:
    1. undefined symbol: _ZTV15fieldInRowModel
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    fieldInRowModel is internal for the library thus the main application should not know that it exists.

    Any idea how to fix it?

    Thanks a lot!
    Carlos.

  2. #2
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    Default Re: undefined symbol while loading plugin

    From plugin you are exposing only interfaces or types known to plugin user (application).
    Apparently you are trying to expose from plugin to some application custom type: fieldInRowModel.
    Type fieldInRowModel should be visible for application as QAbstractTableModel type, nothing more.

  3. #3
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    Default Re: undefined symbol while loading plugin

    Qt Code:
    1. QVariant fieldInRowModel::data(const QModelIndex &/*index*/, int /*role*/) const
    2. {
    3. return QVariant(); //Test value
    4. }
    To copy to clipboard, switch view to plain text mode 

    I guess you might have put your code like that on purpose. Just double check you do aware your code has some problem right? You didn't specify the parameter name in signature of your function definition.
    Dong Back Kim

  4. #4
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    Default Re: undefined symbol while loading plugin

    Hi,

    The problem was related to the way I included some header files, so they were exposed to the plugin user.

    Thanks.

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