How to run a thread as a member function of a class?

[Bob Stanneveld]

Normally, when you use MFC and you create a dialog class, this class has a member called IDD. This is the dialog resource (how the windows looks and what controls are on it). Since I don't know your classes, I don't know why you don't have them, but you can remove the line: : CDialog(...). viveking wrote: D:\CLTRK\CLTRK02\TrayDialog.cpp(487) : error C2664: '__thiscall CTrayDialog::CTrayDialog(unsigned int,class CWnd *)' : cannot convert parameter 1 from 'class CTrayDialog *const ' to 'unsigned int' I must have switched the parameters. So the dialog resource comes second instead of first. If you are wondering what the other parameter is, it's the parent window of the dialog. Behind every great black man...             ... is the police. - Conspiracy brother Blog[^]

[Eytukan]

forget everything.... i'll come with a simpler example.. please wait.:confused: vivek

[Cedric Moonen]

Can you post the header file of your class ? Please use formating tags (the code tag just above the emoticons).

[Eytukan]

Though it looks primitive.. please dont ignore.. see the class test with its data member "text" and function "disp()" i wanna access it from the Thread1 and Thread2.. #include #include #include char fValue[10]; CWinThread *pThread1,*pThread2; UINT Thread1(LPVOID lp) { CClientDC cdc(AfxGetApp()->m_pMainWnd); int j=250; for(int i=1;i<=600;i++) { cdc.TextOut(i,j,"Thread1"); cdc.SetBkColor(0x0009999); Sleep(6); strcpy(fValue,"Thread1"); Text = fValue; ///// I WANT TO ACCESS THE DATA MEMBER "TEXT" FROM CLASS TEST// cdc.TextOut(500,500,Text); } disp();/// HOW TO ACCESS MEMBER FUNCTION "DISP" FROM CLASS TEST// return 0; } UINT Thread2(LPVOID lp) { CClientDC cdc(AfxGetApp()->m_pMainWnd); cdc.SetBkColor(0x0990009); int j=280; for(int i=1;i<=600;i++) { cdc.TextOut(i,j,"Thread1"); Sleep(5); strcpy(fValue,"Thread2"); Text = fValue;///// I WANT TO ACCESS THE DATA MEMBER "TEXT" FROM CLASS "TEST"// cdc.TextOut(500,500,Text); } disp();/// HOW TO ACCESS MEMBER FUNCTION "DISP" FROM CLASS TEST// return 0; } class test { public: CString Text; void disp() { AfxMessageBox(Text); } }; CMenu cm; class MyWindow: public CFrameWnd , public test { public: MyWindow() { Create(0,"Threads of MFC"); } void q() { PostQuitMessage(0); } void Threads() { AfxMessageBox("Starting...."); } DECLARE_MESSAGE_MAP() }; BEGIN_MESSAGE_MAP(MyWindow,CFrameWnd) END_MESSAGE_MAP() class MyWin:public CWinApp { public : BOOL InitInstance() { MyWindow *x; x=new MyWindow; m_pMainWnd=x; pThread1=AfxBeginThread(Thread1,x); pThread2=AfxBeginThread(Thread2,x); x->ShowWindow(SW_SHOWMAXIMIZED); return 1; } }; MyWin App; thanks bob, vivek

[Eytukan]

cedric, my program is too complex.. even i'm worn out looking at the code.. can u post a simple program which wil explain it clearly? should i declare the thread inside the class? just like we do for member functions? i.e class test { public UINT Thread(LPVOID lp); } ?? do we have any alternative for CWinThread? vivek

[David Crow]

viveking wrote: disp();/// HOW TO ACCESS MEMBER FUNCTION "DISP" FROM CLASS TEST// Try:

UINT Thread2(LPVOID lp)
{
MyWindow *mw = (MyWindow *) lp;
mw->disp();
return 0;
}

---

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

[Eytukan]

:(

[Bob Stanneveld]

Hello, Add the following lines of code to TrayDialog.cpp:

CTrayDialog::CTrayDialog() : CDialog(NULL, CTrayDialog::IDD)
{
}

What you are doing here is add the unresolved external symbol (the default contructor), but I think that you need an other solution: change the following code:

void CTrayDialog::TestThread()
{
CTrayDialog *obj;
obj=new CTrayDialog;
pThread=AfxBeginThread(Thread,obj);
}

to:

void CTrayDialog::TestThread()
{
CTrayDialog *obj;
obj=new CTrayDialog(this);
pThread=AfxBeginThread(Thread,obj);
}

Hope this helps. :-D Behind every great black man...             ... is the police. - Conspiracy brother Blog[^]

[Michael Dunn]

See the FAQ 6.1 Why can't I use a member function as a callback?[^] --Mike-- Visual C++ MVP :cool: LINKS~! Ericahist | 1ClickPicGrabber | CP SearchBar v2.0.2 | C++ Forum FAQ Strange things are afoot at the U+004B U+20DD

[Paul Steane]

I suggest you have a look at Joseph M. Newcomer's articles on "Threads and Processes" at http://www.flounder.com/mvp_tips.htm[^]

[Bob Stanneveld]

Hello, Sorry for this late reply.. A couple of things:* You pass a pointer x, that points to a MyWindow object to the thread as parameter, but you don't use it in either of your threads..

• You call AfxGetApp() to get the value of m_pMainWnd

• Your main app window is x

• MyWindow derives from Test Thinking about all these things don't ring a bell? Anyway, what you want to achieve can be done in at least the following 2 ways:

  static_cast<MyWindow*>(AfxGetApp()->m_pMainWnd)->Text;

  static_cast<MyWindow*>(lp)->Text;

  Hope this helps :-D Behind every great black man...             ... is the police. - Conspiracy brother Blog[^]

[Eytukan]

bob,david,cedric,michael, and paul........ paul the link u gave is ultimate.. thank u so much. really resourceful.i think i wont be disturbing u guys again.. everything's there :) The Thread Solution It is almost always the case that you can use threads to do the job more easily. This is not without certain costs and hazards, but it ultimately is the better method. Here's a solution to handling the invert-everything. Note that we have to move from the pure-C domain (which we interface to via a static method) to the MFC domain. To the class (in this example, a CView-derived class), add the following declarations: static UINT run(LPVOID p); void run(); volatile BOOL running; To start a thread, your handler does void CMyView::doInvert() { running = TRUE; AfxBeginThread(run, this); } UINT CMyView::run(LPVOID p) { CMyView * me = (CMyView *)p; me->run(); return 0; } void CMyView::run() { for(int x=y = 0; running && y < image.height; y++) for(int x = 0; running && x < image.width; x++) changePixel(x, y); running = FALSE; } The command to stop the thread is very simple: void CMyView::OnStop() { running = FALSE; } That's all there is to it! :laugh: vivek

[Eytukan]

http://www.flounder.com/workerthreads.htm[^] thank u so much guys, vivek