How to enforce signals to behave as callback

Hi What I want to do is to emit signal as standard callback so that execution blocks until all slots are finished – otherwise it will break logic of my program (emitter depends on actions taken by slots at that time). I now that I can use Qt::AutoConnection (in the same thread), Qt::DirectConnection or Qt::BlockingQueuedConnection but it depends on how the slots are attached to signal’s object (one can connect slots as Qt::QueuedConnection). Is there any way to enforce direct connection ?