Share data accross threads and emit signals

[anda_skoa]

Is this class still thread-safe since it does not use any functions of QObject? What about emit?

That should be ok.

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?

The thread calling the method is the one executing its code.
If the receiver of the signal has a different thread affinity than the thread executing the emit, then the slot will be executed by the receiver's owner thread (assuming Qt::AutoConnection).

However, I would suggest to unlock before emitting, otherwise it is easy to get into a recursive lock situation (e.g. the slot or a methods called from the slot calling a method of this object again).

Cheers,
_