invoke methods in another thread and get return values

[high_flyer]

Just to be clear I understand:
Are you looking for signals/slots with return values other than void, is that it?

[elk]

Yes, it's the slots returning values.

[high_flyer]

I can't test at the moment, but its possible that slots actually can be defined with a return value - however, when used as a slot, how do you want to get the value?
Since you are not calling the slot directly, but only invoke its call (as in emit a signal), and not by the object invoking emitting the signal - so what good would it be for you if the slot is retuning a value - you can't get to that value any way (in the object that emitted the signal)!
Or in other words, you can get the return value only there where the slot is really called - namely in the MetaObject but there you probably wont know what to do with the return value...

Try defining a slot that returns a value and see if the connection works.
If it does, you are still stuck with my question - when and how do you want to get the return value from the slot?

[stampede]

Have you seen QFuture and QtConcurrent ?
This does exactly what you ask in the thread title.

[elk]

If it does, you are still stuck with my question - when and how do you want to get the return value from the slot?

As I did say, I use QMetaObject::invokeMethod().
It is possible to get return value (see Q_RETURN_ARG macro), but only in Qt:irectConnection, i.e. slot will be running in the same thread as a caller object. But I need it running in another thread. It can be achieved only in queued connection, in this case invokeMethod() with the Q_RETURN_ARG is useless. But I can write some data in memory passing its pointer as a slot argument (using Qt::BlockingQueuedConnection, of course). But I thought there is another way similar to invokeMethod() with Q_RETURN_ARG.

int someValue() is more beautiful than void giveMeSomeValue(int *where).

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Added after 11 minutes:

This does exactly what you ask in the thread title.

Can I select a particular QThread from global pool?

[stampede]

Try defining a slot that returns a value and see if the connection works.

Yes, connection to a slot returning value works ok.

Can I select a particular QThread from global pool?

I don't know, why do you need a particular thread to run your code ?

[elk]

I don't know, why do you need a particular thread to run your code ?

Because that code interacts with a network (QTcpSocket)