HWND is the type used by windows for window handles. It's what get's returned by CreateWindow() and is passed into DestroyWindow(). As for checking it, just set a breakpoint in your debugger and check the value of the variable in which you store the result of CreateWindow() (in VS you can just hold your mouse over the variable and it should show it's value). Also set a breakpoint just before you call DestroyWindow() and check that value that you pass in, it *should* be the same as what was returned by CreateWindow().
Post you're WinMain(), init and uninit code. It should help.
Another problem - DestroyWindow(hWnd) causes error
Author
I think the debugger in Dev-C++ is not that useful... anyway, here is my CreateWindow call
It is commented in German, sorry for that (now you know why my English is that bad ;) ).
And here is my de-init code:
Thanks for you patience so far.
hWnd=CreateWindowEx( dwExStyle, // Die erweiterten Eigenschaften des Fensters szClass, // Der Name der Klasse title, // Der Titel des Fensters WS_CLIPSIBLINGS | // Wird von OpenGL benötigt WS_CLIPCHILDREN | // Wird auch von OpenGL benötigt dwStyle, // auch Eigenschaften des Fensters 0, 0, // Die Position des zu erstellenden Fensters WindowRect.right-WindowRect.left, // Hier werden die ermittelten Werte für die Breite eingesetzt WindowRect.bottom-WindowRect.top, // und hier für die Länge NULL, // Es soll kein übergordnetes Fendster erstellt werden NULL, // kein Menü hInstance, // Die Instanz wird übergeben NULL)It is commented in German, sorry for that (now you know why my English is that bad ;) ).
And here is my de-init code:
if (hRC) // Rendering Context (RC) vorhanden? { if (!wglMakeCurrent(NULL,NULL)) // Kann der DC und RC überhaupt // gelöscht werden? { MessageBox(NULL,"Entfernen des DC und RC fehlgeschlagen.","Fehler",MB_OK | MB_ICONINFORMATION); }; if (!wglDeleteContext(hRC)) // Kann der RC gelöscht werden? { MessageBox(NULL,"Entfernen des RC fehlgeschlagen.","Fehler...",MB_OK | MB_ICONINFORMATION); }; hRC=NULL; // Der RC wird NULL gesetzt, also entfernt }; if (hDC && !ReleaseDC(hWnd,hDC)) // Kann der Device Context (DC) freigegeben werden? { MessageBox(NULL,"Freigabe des Device Context fehlgeschlagen.","Fehler",MB_OK | MB_ICONINFORMATION); hDC=NULL; // Der DC wird entfernt }; // ***** Here the program crashes as DestroyWindow is called ****** if (hWnd && !DestroyWindow(hWnd)) // Kann das Programmfenster geschlossen werden? { MessageBox(NULL,"Konnte hWnd nicht löschen.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION); hWnd=NULL; // Setze den hWnd auf NULL }; if (!UnregisterClass(szClass,hInstance)) // Kann die Registrierung rückgängig gemacht werden? { MessageBox(NULL,"Konnte Klasse nicht entfernen.","SHUTDOWN ERROR",MB_OK | MB_ICONINFORMATION); hInstance=NULL; // Setze hInstance auf NULL };[...]Thanks for you patience so far.
Author
Heureka, I got it! I have been so stupid I can not believe... After deinitialising the Window I have made a MessageBox-call to check if everything has been shut down correctly, and in that call I passed hWnd as first parameter, as the parent window. But of course the window was already destroyed and so this little MessageBox crashed the program.
So I am very sorry for wasting your time, but during the checking for memory lecks I have found some of them in some of my classes, so the whole thing also has its positive effect.
Again, thanks for you patience =)
So I am very sorry for wasting your time, but during the checking for memory lecks I have found some of them in some of my classes, so the whole thing also has its positive effect.
Again, thanks for you patience =)
I can't see anything wrong in the code you pasted... Anyway, you can use the GetLastError() and FormatMessage() functions to know why it is failing.
LPVOID lpMsgBuf;FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM, NULL, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language (LPTSTR) &lpMsgBuf, 0, NULL );// Display the string.MessageBox( NULL, lpMsgBuf, "GetLastError", MB_OK|MB_ICONINFORMATION );// Free the buffer.LocalFree( lpMsgBuf );Quote:Original post by Marco H
Heureka, I got it! I have been so stupid I can not believe... After deinitialising the Window I have made a MessageBox-call to check if everything has been shut down correctly, and in that call I passed hWnd as first parameter, as the parent window. But of course the window was already destroyed and so this little MessageBox crashed the program.
So I am very sorry for wasting your time, but during the checking for memory lecks I have found some of them in some of my classes, so the whole thing also has its positive effect.
Again, thanks for you patience =)
LOL! No worries [smile]
As a side note, you're english is a lot better than some native speakers of the language that I know....
Quote:Original post by theNestruo
Anyway, you can use the GetLastError() and FormatMessage() functions to know why it is failing.
Good suggestion in general, but the program was crashing so it wouldn't help in this case.
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