Question

I have an RPC thread that is calling back to me from that thread. I need to somehow inform Qt that it needs to make a function call from the main thread. In straight Windows I could do this by using a custom message and then posting that message to the message queue, e.g., I could create a WM_CALLFUNCTION message and pass the function pointer through wParam and the parameter (class pointer) through lParam.

Has anyone an idea how I could do this with Qt? I’ve come across QCustomEvent but I have no idea how to use it or how to process it. Any help would be hugely appreciated!

Edit:

In the end I went with QMetaObject::invokeMethod which works perfectly.

Answer 1

In Qt 3, the usual way to communicate
with the GUI thread from a non-GUI
thread was by posting a custom event
to a QObject in the GUI thread. In Qt
4, this still works and can be
generalized to the case where one
thread needs to communicate with any
other thread that has an event loop.

To ease programming, Qt 4 also allows
you to establish signal–slot
connections across threads. Behind the
scenes, these connections are
implemented using an event. If the
signal has any parameters, these are
also stored in the event. Like
previously, if the sender and receiver
live in the same thread, Qt makes a
direct function call.

—
http://doc.qt.nokia.com/qq/qq14-threading.html#signalslotconnectionsacrossthreads