[Qt-interest] QThread Question

[Sean Harmer]

Hi Donal,

On Thursday 06 Aug 2009 12:10:57 Donal O'Connor wrote:
> Ok I see but actually looking at the code, there are some instance's where
> it is just a regular method and not a slot. Does this mean, when the method
> is called, that it is run in the calling thread?
Yes, as there is no mechanism to switch it over to the other thread in this 
case. It is just a direct call. The same applies even if the function is a 
slot but is called directly.

Queued connections hand the call over to the worker thread by posting to the 
worker thread's event queue. This event is interpreted by the thread's exec() 
function which then calls the appropriate slot with the correct arguments. 
This is why you must enter the event loop (by calling exec()) in order to get 
signals/slots working across thread boundaries.

> Plus, no where have specified the connection type to be Queued, I'm
> assuming direct connection is the default and this results in the slot
> being called in the calling thread?
If the thread has been moved to itself, then this is not strictly necessary as 
connect() figures this out for you. However, when dealing with threads I find 
it useful to be explicit to minimise confusion/ambiguity.

> Bit of a mess the code here!
Good luck!

Sean