Re: Getting thread to stop in CDialog type class
<andreas.zetterstrom@gmail.com> wrote in message
news:39e33a6a-dbc7-466f-b578-0aee7ff42089@z1g2000yqn.googlegroups.com...
Let's see if I can explain this...
I have a class based on a standard CDialog, in it I have a thread
which loops every 100 ms. This thread has two purposes;
1) it invalidates a painting area, forcing the dialog to redraw even
if windows don't see it as nessesary
2) it updates values in various labels and such
My problem is with #2, and specifically when the app is about to exit.
At OnDestroy I have to stop the thread, as after OnDestroy has
finished the hWnds to all child labels are not usable anymore. To do
this I wait in OnDestroy for the thread to finish its current cycle
(using a semaphore), and then stop it. The problem is that writing
data to the labels is essentially sending a message to the message
queue, and the message queue is at the moment stopped in OnDestroyed
(I think), thus a deadlock! I can't for the life of me figure out how
to reliably stop the thread without this deadlock occuring.
Move the code to destroy the thread earlier in the lifetime of the dialog.
OnDestroy is too late. Perhaps OnClose, but I'm not sure if this is called
for a dialog. If not, perhaps override OnOK and OnCancel.
-- David