Original Post
Hi.
I have discovered a problem with multithreading processes in my program. Here is an example.
- program starts
- CMyProgramApp::InitInstance() calls RestoreState() in CMainFrame()
- RestoreState() restores the windows positions via registry
- RestoreState() restores data (int, char, binary, etc) from registry to variables in CMyProgramDoc()
- RestoreState() calls a function in CMyProgramDoc() which begins a worker thread
- worker thread does some calculation
Problem: For some reason, I have found that if the calculation is big i.e. it takes a long time, the thread never gets closed and deleted.
The worker thread PostMessage main frame a message indicating that it is done. However, sometimes main frame never received the message!
-----
UINT WorkerThreadFunc(LPVOID pParam)
{
...
pWnd->PostMessage(WM_USER_WORKERTHREAD_CLOSED, 0, 0);
return 0;
-----
There is a handler in main frame to handle the message that class a function in doc to close the worker thread; however, I found that if the worker thread takes a long time to finish a calculation, main frame never receive or ignores the PostMessage.
The only problem I can think of right now is I am starting the worker thread too early. In other words, I should start the worker thread after the program has started and all window positions have been restored.
Do you see any other flaws? Please post.
Thanks,
Kuphryn
ostMessage(HWND, MESSAGE, 0, 0) instead, as this is how the documentation says to communicate with the parent window. MFC keeps track of which thread owns what, so maybe it won't let you access the message queue of the other window that way.