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There are two methods. I've included code with both. I used a bool to signal the other thread, but vastly prefer using events since threads often have waits within them. Also note that I can't remember the last time I checked a thread exit code, but you may have a reason. Finally, if you don't call MFC within the thread (with a few exceptions), you could just use _beginthreadex(). I just did this last week.
1) Call AfxBeingThread() with the CREATE_SUSPENDED flag.
2) set CWinThread::m_bAutoDelete to false
3) Call CWinThread::Resume()
4) At exit, after setting the bool (or setting an event, which is my preferred method), call WaitOnSingleObject() with CWinThread::m_hThread
5) Call GetThreadExitCode() to get exit code
6) Delete the CWinThread object
I've run into problems with MFC complaining about item 6.
CWinThread* StartAfxThread(AFX_THREADPROC pThreadProc, LPVOID pParam = NULL, int priority = THREAD_PRIORITY_NORMAL)
{
CWinThread* pThread = ::AfxBeginThread(pThreadProc, pParam, priority, 0, CREATE_SUSPENDED);
pThread->m_bAutoDelete = false;
pThread->ResumeThread();
return pThread;
}
CWinThread* pThread = StartAfxThread(TheThread);
isRunning = false;
if (::WaitForSingleObject(pThread->m_hThread, 1000) == WAIT_TIMEOUT)
{
::TerminateThread(pThread->m_hThread, (DWORD) -1);
Sleep(10);
}
DWORD exitCode = 0;
::GetExitCodeThread(pThread->m_hThread, &exitCode);
_tprintf(_T("Exit code: %u"), exitCode);
delete pThread;
1) Call AfxBeingThread() with the CREATE_SUSPENDED flag.
2) Duplicate CWindThread::m_hThread
3) Call CWinThread::Resume()
4) At exit, after setting the bool, call WaitOnSingleObject() with the duplicate handle.
5) Call GetThreadExitCode() to get exit code
6) Close the duplicate handle
HANDLE StartAfxThread(AFX_THREADPROC pThreadProc, LPVOID pParam = NULL, int priority = THREAD_PRIORITY_NORMAL)
{
CWinThread* pThread = ::AfxBeginThread(pThreadProc, pParam, priority, 0, CREATE_SUSPENDED);
HANDLE hProcess = GetCurrentProcess();
HANDLE hDup;
if (!::DuplicateHandle(hProcess, pThread->m_hThread, hProcess, &hDup, 0, FALSE, DUPLICATE_SAME_ACCESS))
hDup = NULL;
pThread->ResumeThread();
return hDup;
}
HANDLE hThread = StartAfxThread(TheThread);
isRunning = false;
if (::WaitForSingleObject(hThread, 1000) == WAIT_TIMEOUT)
{
::TerminateThread(hThread, (DWORD) -1);
Sleep(10);
}
DWORD exitCode = 0;
::GetExitCodeThread(hThread, &exitCode);
_tprintf(_T("Exit code: %u"), exitCode);
CloseHandle(hThread);
Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke
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When the user clicks cancel, I don't want the window to close if the thread is still running. I want to have the thread safely finish first.
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
DWORD exitcode;
GetExitCodeThread(hTread->m_hThread, &exitcode);
if (exitcode != STILL_ACTIVE )
OnCancel();
-@SuDhIrKuMaR@-
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By default a CWinThread object with auto delete itself upon thread exit. Not only will the thread handle within be invalid, the pointer itself will be invalid.
Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke
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hi all,
anyone have a idea the meaning of the bold lines.
using child pointer to a the parent class.
class CPolygon {
protected:
int width, height;
public:
void set_values (int a, int b)
{ width=a; height=b; }
//virtual int area (void) =0;
virtual int area (void)
{return 0;}
void printarea (void)
{ cout << this->area() << endl; }
};
class CTriangle: public CPolygon {
public:
int area (void)
{ return (width * height / 2); }
int test;
};
int main () {
CRectangle rect;
CTriangle trgl;
CPolygon * ppoly1 = ▭
CPolygon * ppoly2 = &trgl;
CTriangle * ptrgl = (CTriangle *) ▭
ppoly1->set_values (4,5);
ppoly2->set_values (4,5);
ptrgl->set_values (4,5);
ppoly1->printarea();
ppoly2->printarea();
ptrgl->printarea();
ptrgl->test = 1;
cout << ppoly1->area() << endl;
cout << ppoly2->area() << endl;
cout << ptrgl->area() << endl;
system("PAUSE");
return EXIT_SUCCESS;
}
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The definition of CRectangle isn't present so I can't tell if the cast makes sense. I have to say it look like nonsense to me however. Also, as a general rule avoid C-style casts.
Steve
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Let me restate my question
below code can be compile and run with no problem. but, i confused how the bold line works. I have not initialzed a CTriangle object in the bold line but i can access the data by a CTriangle pointer.
I dont think it is a good practice but i am quite confused how it works...
class CPolygon {
protected:
int width, height;
public:
void set_values (int a, int b)
{ width=a; height=b; }
virtual int area (void)
{return 0;}
void printarea (void)
{ cout << this->area() << endl; }
};
class CTriangle: public CPolygon {
public:
int area (void)
{ return (width * height / 2); }
int testdata;
};
int main () {
CPolygon poly;
CTriangle trgl;
CPolygon * ppoly2 = &trgl;
CTriangle * ptrgl = (CTriangle *) &poly;
ppoly2->set_values (4,5);
ptrgl->set_values (4,5);
ppoly2->printarea();
ptrgl->printarea();
ptrgl->testdata = 100;
cout << ppoly1->area() << endl;
cout << ppoly2->area() << endl;
cout << ptrgl->area() << endl;
cout << ptrgl->testdata << endl;
system("PAUSE");
return EXIT_SUCCESS;
}
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The fact that it works is a fluke. The local poly is NOT a CTriangle. It just so happens that in the two classes the vtable[^] pointer is at the same location as are the first two members (width and height). Accessing testdata (via ptrgl) is wrong in this code. Also the wrong instance of virtual functions will be called. If I could give a single piece of advice to new C++ programmers it would be to stop casting yourself into strife.
Steve
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I search the boards to no avail.
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CString strText("GOOD");
char *pChar= (char *)(LPCTSTR)strText;
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Please never suggest that unless you further elaborate.
Such conversion may be used only with extreme care.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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Do you mean to say i should elaborate what i have given there an an example?
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I mean since your technique is dangerous hence you should explicitely state whenever it is viable.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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I have been looking for a way to access the dictionary in windows.
I have found how to spell check and to edit the dictionary but that is doing a comparison of words in a file utilizing msword.olb in C++.
I am looking to pull a word from the dictionary with the option of pulling the definition with it. Is that possible within the C++/.net environment to utilize the dictionary built into word or word pad this way?
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Hi
I want to make a program that retrieves other windows' pixel values. First i made a default application which title name is "Untitled - NewWindow" and one more MFC project which is trying to draw to that window.
The code is:
void CDeviceContextDlg::OnBnClickedButton1()
{
::EnumWindows(EnumWindowsProc, NULL);
}
BOOL CALLBACK EnumWindowsProc(HWND hwnd, LPARAM lParam)
{
if(hwnd == FindWindow(NULL,L"Untitled - NewWindow"))
{
HDC dc = GetDC(hwnd);
CDeviceContextDlg *dlg = (CDeviceContextDlg *)AfxGetMainWnd();
if((dlg->Clientdc.Attach(dc)))
{
dlg->Clientdc.SetBkColor(RGB(255,0,0));
};
};
return TRUE;
}
It gives run-time error. I debugged it and in that line:
HDC dc = GetDC(hwnd);
In Debugger:
dc 0x53011041 {unused=??? } HDC__ *
unused CXX0030: Error: expression cannot be evaluated
Is it because process gdi handle table is process specific and it is impossible to get DC and draw another process' window?
Or is there a way to draw another process' window or getpixel values?
Thanks
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Maybe this [^] helps.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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Just fixed the vote on this post of yours. 
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Thank you friend. ![Rose | [Rose]](https://www.codeproject.com/script/Forums/Images/rose.gif)
Anyway don't bother. Let's my personal troll having a touch of glory...
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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I am searching ebay for a device that would let you find and punch one troll at a time, with a folded fist, through the internet.
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Well, you can buy one (ore more) of these [^] and then proceed with voodoo ceremony.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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I tested this real quick, and it works fine for me.
This example finds a NotePad instance and Blts the Notepad window
to my window (note that "*pThis" in the callback == the HWND for the dialog window)...
BOOL CALLBACK CMFCTesterDlg::EnumWindowsProc(HWND hwnd, LPARAM lParam)
{
if(hwnd == ::FindWindow(NULL, L"Untitled - Notepad"))
{
CMFCTesterDlg *pThis = (CMFCTesterDlg *)lParam;
HWND hwnddest = *pThis;
RECT rect;
::GetWindowRect(hwnd, &rect);
HDC dc = ::GetDCEx(hwnd, NULL, DCX_WINDOW);
HDC destdc = ::GetDC(hwnddest);
::BitBlt(destdc, 0, 0, rect.right-rect.left, rect.bottom-rect.top, dc, 0, 0, SRCCOPY);
::ReleaseDC(hwnddest, destdc);
::ReleaseDC(hwnd, dc);
};
return TRUE;
}
void CMFCTesterDlg::OnOK()
{
::EnumWindows(&CMFCTesterDlg::EnumWindowsProc, (LPARAM)this);
}
Also, why the search within a search (FindWindow() within an EnumWindows() callback)??
Mark Salsbery
Microsoft MVP - Visual C++
![Java | [Coffee]](https://www.codeproject.com/script/Forums/Images/coffee.gif)
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Thank you Mr.Mark Salsbery. Got it. 
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iwdu150
I have tried your Percent Progress Bar, and have use it in a application I am building. What I mean is I am using the DLL and the XML. This application that I am building is for my own use and will not be release to the public. The DLL and XML have really come in handy and I have enjoyed using. You did a good job.
The reason I am contacting you is that I noticed that the word ‘TRIAL’ is tacked onto the name ‘Progress Bar Trial.dll’ and ‘Progress Bar Trial.xml’. This has me a little worried, will it expire or maybe die on me in the near future. If not then great; but if so, please let me know. Also let me know how I can get a good copy of it. Once again, great job, I hope I can use it just the way it is.
Bob Allan
rallan@carolina.rr.com
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