Important: Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

Can't find linker symbol for virtual table for 'QMutexLocker' value



  • I have a class which allows the user read/write access to a array.
    mem.h
    @
    typedef std::auto_ptr<QByteArray> QByteArrayPtr;
    class mem : public QObject
    {
    Q_OBJECT
    public:
    explicit mem(QObject *parent = 0) : QObject(parent ) {}
    void CleanUp();

    qint32 Write (const QByteArray pbuf);
    QByteArrayPtr Read(const qint32 timeout = ULONG_MAX);
    

    private:
    QMutex mutex;
    QWaitCondition cond;
    QList<QByteArray*> pblock;// memory block

    };
    @

    mem.c

    @
    void mem::CleanUp()
    {
    int size = 0;
    int i;
    QMutexLocker locker(&mutex);
    size = pblock.size();
    for (i=0;i<size;i++) {
    QByteArray *pbuf = pblock.at(0);
    pbuf->clear();
    delete pbuf;
    }
    }

    qint32 mem::Write(const QByteArray pbuf)
    {
    qint32 writebytes = 0;
    QMutexLocker locker(&mutex);

    if (pblock.size() >= 16) {
            return 0;
    }
    
    QByteArray *newpbuf = new QByteArray;
    *newpbuf = pbuf;
    pblock << newpbuf;
    writebytes = pbuf.size();
    cond.wakeOne();
    
    return writebytes;
    

    }

    QByteArrayPtr mem::Read(const qint32 timeout)
    {
    QByteArrayPtr block;
    QMutexLocker locker(&mutex);
    if (pblock.size() == 0) {
    cond.wait(locker.mutex(), timeout);
    }

    if (pblock.size() != 0) {
    block.reset(pblock.at(0));
    pblock.removeAt(0);
    }
    return block;
    }
    @

    after saving the data into mem i try to read them. But i got the error
    can't find linker symbol for virtual table for 'QMutexLocker' value
    QMutex::lock: Deadlock detected in thread 368
    Do you have any ideas where i do wrong?
    Thank you



  • Are those two errors from the same run? Because if the symbol cannot be found, that is (dynamic) link time error, while the error from QMutex::lock() is a runtime error.

    If they are from the same run, it looks like your app is picking up a different Qt library than you link your project with.


Log in to reply