Consider introducing a QTryMutexLocker in addition to QMutexLocker

class QTryMutexLocker
{
public:  
  QTryMutexLocker(QMutex &m, int timeout = 0);  ~TryMutexLocker();
  bool isLocked() const;
private:  
  QMutex &m_mutex;  bool m_locked;
};

QTryMutexLocker::QTryMutexLocker(QMutex &m, int timeout)
    : m_mutex(m)
    , m_locked(m.tryLock(timeout))
{
}

QTryMutexLocker::~QTryMutexLocker()
{
    if(m_locked)
        m_mutex.unlock();
}

bool QTryMutexLocker::isLocked() const
{
    return m_locked;
}