Share data accross threads and emit signals

[Lykurg]

Hi,

I need to have access to several information from different threads so I made a class like this:

class Foo
{
  public:
    void increase()
    {
      QWriteLocker l(&m_lock);
      m_ints << 42;
    }
 
  private:
    QReadWriteLock m_lock;
    QVector<int> m_ints;
};

class Foo
{
  public:
    void increase()
    {
      QWriteLocker l(&m_lock);
      m_ints << 42;
    }

  private:
    QReadWriteLock m_lock;
    QVector<int> m_ints;
};

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Foo is then instantiated in the main thread and a pointer is passed to the relevant threads. So far so good. Now I'd like to get informed if e.g. m_ints gets changed. So QObject came into play but as it is only reentrant (except connect and disconnect) it is getting complicated.

Let's think of this modified class:

class Foo : public QObject
{
  public:
    Foo: QObject(0) {}
 
    void increase()
    {
      QWriteLocker l(&m_lock);
      m_ints << 42;
      emit added(42);
    }
 
  signals:
    void added(int);
 
  private:
    QReadWriteLock m_lock;
    QVector<int> m_ints;
};

class Foo : public QObject
{
  public:
    Foo: QObject(0) {}

    void increase()
    {
      QWriteLocker l(&m_lock);
      m_ints << 42;
      emit added(42);
    }

  signals:
    void added(int);

  private:
    QReadWriteLock m_lock;
    QVector<int> m_ints;
};

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So, Foo's thread affinity is my main thread.

1. Is this class still thread-safe since it does not use any functions of QObject? What about emit?
2. What does this mean for calling increase() through a pointer from a different tread. Which thread does the "work" (manipulating m_ints) of increase(): The main thread or the local thread?

If that solution is bad, what would be a good approach to get informed about changes? (Beside the caller of the function emits afterwards the changes ala

myFoo->increase();
emit mySignalAdded(42);

myFoo->increase();
emit mySignalAdded(42);

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Thanks
Lykurg