@kshegunov Right... Thanks, something didnt trigger in the brain. Now its fine:

connect(uap, &CUaProxy::uaItemChanged, this, [this, i]( const CUaProxy::MsgType msgt, const int riskIndex, const QVariant& value) { this->onUaMsgReceived(msgt, i, riskIndex, value); }, Qt::QueuedConnection);

Also needed Qt::QueuedConnection eventually.

@jsulm
Yeah, i understand (just forget to start thread). In that example thread->start() was called though.
In the last example deletion of ThreadEx object should be handled by application main loop.

@abforce said in Looking for the best multithreading patterns for database access:

For this purpose can I employ a callback pattern?

You can simply use signals/slots across threads

You're welcome !

Since you have it working now, please mark that thread as solved using the "Topic Tools" button so that other forum users may know a solution has been found :)