Polygon 2

It compiles but it wont executes, it goes in debug mode VC++ 2008.
I dont understand whats wrong.

Code:

---

#include <windows.h>

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdLine, int iCmdShow)
{
    static TCHAR szAppName[] = TEXT ("AltWind") ;
    HWND        hwnd ;
    MSG          msg ;
    WNDCLASS    wndclass ;
   
    wndclass.style        = CS_HREDRAW | CS_VREDRAW ;
    wndclass.lpfnWndProc  = WndProc ;
    wndclass.cbClsExtra    = 0 ;
    wndclass.cbWndExtra    = 0 ;
    wndclass.hInstance    = hInstance ;
    wndclass.hIcon        = LoadIcon (NULL, IDI_APPLICATION) ;
    wndclass.hCursor      = LoadCursor (NULL, IDC_ARROW) ;
    wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
    wndclass.lpszMenuName  = NULL ;
    wndclass.lpszClassName = szAppName ;
   
    hwnd = CreateWindow (szAppName, TEXT ("Alternate and Winding Fill Modes"),
                          WS_OVERLAPPEDWINDOW,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          NULL, NULL, hInstance, NULL) ;
   
    ShowWindow (hwnd, iCmdShow) ;
    UpdateWindow (hwnd) ;
   
    while (GetMessage (&msg, NULL, 0, 0))
    {
          TranslateMessage (&msg) ;
          DispatchMessage (&msg) ;
    }
    return msg.wParam ;
}

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    static int  cxClient, cyClient ;
    HDC          hdc ;
    PAINTSTRUCT  ps ;
    static POINT        points [7] = { {20,50}, {180,50}, {180,20}, {230,70}, {180,120}, {180,90}, {20,90} } ;
   
    switch (message)
    {
    case WM_SIZE:
          cxClient = LOWORD (lParam) ;
          cyClient = HIWORD (lParam) ;
          return 0 ;

    case WM_PAINT:
          hdc = BeginPaint (hwnd, &ps) ;

          SelectObject (hdc, GetStockObject (GRAY_BRUSH)) ;
          Polygon(hdc, points, 7) ;
         
          EndPaint (hwnd, &ps) ;
          return 0 ;
         
    case WM_DESTROY:
          PostQuitMessage (0) ;
          return 0 ;
    }
    return DefWindowProc (hwnd, message, wParam, lParam) ;
}

---

Before you CreateWindow you need to RegisterClass. You should also check the return value of CreateWindow to make sure the window is valid.

Thanks, i added RegisterClass but still the same.

Code:

---

#include <windows.h>

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdLine, int iCmdShow)
{
    static TCHAR szAppName[] = TEXT ("AltWind") ;
    HWND        hwnd ;
    MSG          msg ;
    WNDCLASS    wndclass ;
   
    wndclass.style        = CS_HREDRAW | CS_VREDRAW ;
    wndclass.lpfnWndProc  = WndProc ;
    wndclass.cbClsExtra    = 0 ;
    wndclass.cbWndExtra    = 0 ;
    wndclass.hInstance    = hInstance ;
    wndclass.hIcon        = LoadIcon (NULL, IDI_APPLICATION) ;
    wndclass.hCursor      = LoadCursor (NULL, IDC_ARROW) ;
    wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
    wndclass.lpszMenuName  = NULL ;
    wndclass.lpszClassName = szAppName ;
   
        if (!RegisterClass (&wndclass))
    {
          MessageBox (NULL, TEXT ("Program requires Windows NT!"),
                      szAppName, MB_ICONERROR) ;
          return 0 ;
    }
   
    hwnd = CreateWindow (szAppName, TEXT ("Polygon"),
                          WS_OVERLAPPEDWINDOW,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          NULL, NULL, hInstance, NULL) ;
   
    ShowWindow (hwnd, iCmdShow) ;
    UpdateWindow (hwnd) ;
   
    while (GetMessage (&msg, NULL, 0, 0))
    {
          TranslateMessage (&msg) ;
          DispatchMessage (&msg) ;
    }
    return msg.wParam ;
}

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    static int  cxClient, cyClient ;
    HDC          hdc ;
    PAINTSTRUCT  ps ;
        static POINT        points [7] = { {20,50}, {180,50}, {180,20}, {230,70}, {180,120}, {180,90}, {20,90} } ;
   
    switch (message)
    {
    case WM_SIZE:
          cxClient = LOWORD (lParam) ;
          cyClient = HIWORD (lParam) ;
          return 0 ;

    case WM_PAINT:
          hdc = BeginPaint (hwnd, &ps) ;

                  SelectObject (hdc, GetStockObject (GRAY_BRUSH)) ;
                  Polygon(hdc, points, 7) ;
         
          EndPaint (hwnd, &ps) ;
          return 0 ;
         
    case WM_DESTROY:
          PostQuitMessage (0) ;
          return 0 ;
    }
    return DefWindowProc (hwnd, message, wParam, lParam) ;
}

---

I don't know what to tell you then. I used the exact code as above, in Visual Studio 2008 and it runs.

Does anything display for you? Are you getting the error message if RegisterClass fails? Are you checking the window handle after CreateWindow?

Thanks, thats all i needed to know. If it runs for you i got a bug in my system.

No error message whatsoever btw.