Re: Child / Parent windows not in same thread

From:
"ScottMcP [MVP]" <scottmcp@mvps.org>
Newsgroups:
microsoft.public.vc.mfc
Date:
Thu, 21 Jun 2012 11:20:02 -0700 (PDT)
Message-ID:
<b2946cdc-6b8a-46f0-af20-2fd79d60815c@googlegroups.com>
On Thursday, June 21, 2012 1:35:53 PM UTC-4, Maja wrote:

On Jun 21, 5:05 pm, "ScottMcP [MVP]" <scott...@mvps.org> wrote:

But, if I can be sure that both the message loops of the main thre=

ad

and my second thread are alive, and I don't hold any locks , I can ge=

t

away without this deadlocks problems ? or no


It would probably work if, as you say, both the message loops are alive=

.. But it's not good enough for your thread to hold no locks. The main threa=
d also has to hold no locks.

 
 
Thank you for quick reply
One more question
 
Now after I think more , maybe I can't be that sure, so I am in a
doubt if I should do this thread thing at all.
 
 I found the following post
 
http://groups.google.com/group/microsoft.public.win32.programmer.ole/brow=

se_thread/thread/f4d67cb4d0b085c0/8f463a49544f48fc?lnk=gst&q=Validity+o=
f+creating+a+child+window+in+a+separate+process#8f463a49544f48fc

which suggests that creating the window as WS_POPUP instead as
WS_CHILD is more secure, so if this is true does it mean that no
chance for deadlocks exists ?


Using WS_POPUP, and passing NULL as the hwndParent, will make sure that you=
r window will not have a parent/child relationship with the main thread win=
dows. However, you are still subject to possible deadlocks if you SendMess=
age to any window created in another thread.

The combination of WS_POPUP and never using SendMessage to the other thread=
 should make you safe from deadlocks. (And it is OK to use PostMessage to =
the other thread.)

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