Re: Need help solving a threading issue

"Scott McPhillips [MVP]" <org-dot-mvps-at-scottmcp>
Mon, 30 Jul 2007 00:48:34 -0400
shadowulf wrote:

Hi folks,

I have an MFC application that has some GUI functionality. It's main
thead creates a worker thread (using AfxBeginThread), and this worker
thread needs to create an instance of a class (which we'll call
'network' for now) which does some TCP/IP networking stuff;
functionality achieved by inheriting from another class. Also, The
'network' class and the main thead talk to each other via PostMessage.

Now my problem is that I can't figure out how to instantiate the
network class to get everything to work. Here's my attempts and
resultant failures:

ATTEMPT 1) I tried making the network class derive from CDialog to
support windows messaging. It uses a plain dialog resource and calls
ShowWindow(FALSE) since i'm not aqctually interested in any GUI
functionality in the network class. But if the worker thread creates
the network class and calls DoModal on it, the network class stops the
main thread from receiving any GUI interaction.

When you create a worker thread you cannot use CDialog in it. A worker
thread does not have an MFC message pump, but CDialog relies on having
an MFC message pump in-thread.

In what way do you want to support windows messaging for your network
class? If you want CAsyncSocket/CSocket to work then you MUST create a
UI thread, not worker thread.

Scott McPhillips [MVP VC++]

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