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OpenGL beginning openGL game programming compile error

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Lonefox1    140
Hi there, ive just got the book beginning openGL Game Programming by dave astle and kevin hawkins. Im trying to compile the second lesson, im getting this error: In function `int WinMain(HINSTANCE__*, HINSTANCE__*, CHAR*, int)': 215 [Warning] passing NULL used for non-pointer converting 1 of `HWND__* CreateWindowExA(DWORD, const CHAR*, const CHAR*, DWORD, int, int, int, int, HWND__*, HMENU__*, HINSTANCE__*, void*)' Im using DevCPP latest version for compiling. The warning only pops up when i do a rebuild all, just compiling the files one at a time gives no warnings. Any ideas why its having this problem? heres the function:
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd)
    WNDCLASSEX windowClass;     // window class
    HWND       hwnd;            // window handle
    MSG        msg;             // message
    DWORD      dwExStyle;       // Window Extended Style
    DWORD      dwStyle;         // Window Style
    RECT       windowRect;

    g_glRender = new CGfxOpenGL;

    windowRect.left=(long)0;                        // Set Left Value To 0
    windowRect.right=(long)windowWidth; // Set Right Value To Requested Width;                         // Set Top Value To 0
    windowRect.bottom=(long)windowHeight;   // Set Bottom Value To Requested Height

    // fill out the window class structure
    windowClass.cbSize          = sizeof(WNDCLASSEX);           = CS_HREDRAW | CS_VREDRAW;
    windowClass.lpfnWndProc     = MainWindowProc;
    windowClass.cbClsExtra      = 0;
    windowClass.cbWndExtra      = 0;
    windowClass.hInstance       = hInstance;
    windowClass.hIcon           = LoadIcon(NULL, IDI_APPLICATION);  // default icon
    windowClass.hCursor         = LoadCursor(NULL, IDC_ARROW);      // default arrow
    windowClass.hbrBackground   = NULL;                             // don't need background
    windowClass.lpszMenuName    = NULL;                             // no menu
    windowClass.lpszClassName   = "GLClass";
    windowClass.hIconSm         = LoadIcon(NULL, IDI_WINLOGO);      // windows logo small icon

    // register the windows class
    if (!RegisterClassEx(&windowClass))
        return 0;

    if (fullscreen)                             // fullscreen?
        DEVMODE dmScreenSettings;                   // device mode
        dmScreenSettings.dmSize = sizeof(dmScreenSettings); 
        dmScreenSettings.dmPelsWidth = windowWidth;         // screen width
        dmScreenSettings.dmPelsHeight = windowHeight;           // screen height
        dmScreenSettings.dmBitsPerPel = windowBits;             // bits per pixel

        if (ChangeDisplaySettings(&dmScreenSettings, CDS_FULLSCREEN) != DISP_CHANGE_SUCCESSFUL)
            // setting display mode failed, switch to windowed
            MessageBox(NULL, "Display mode failed", NULL, MB_OK);
            fullscreen = FALSE; 

    if (fullscreen)                             // Are We Still In Fullscreen Mode?
        dwExStyle=WS_EX_APPWINDOW;                  // Window Extended Style
        dwStyle=WS_POPUP;                       // Windows Style
        ShowCursor(FALSE);                      // Hide Mouse Pointer
        dwExStyle=WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;   // Window Extended Style
        dwStyle=WS_OVERLAPPEDWINDOW;                    // Windows Style

    AdjustWindowRectEx(&windowRect, dwStyle, FALSE, dwExStyle);     // Adjust Window To True Requested Size

    // class registered, so now create our window
    hwnd = CreateWindowEx(NULL,                                 // extended style
        "GLClass",                          // class name
        "BOGLGP - Chapter 2 - OpenGL Application",      // app name
        dwStyle | WS_CLIPCHILDREN |
        0, 0,                               // x,y coordinate
        windowRect.right - windowRect.left,
        windowRect.bottom -, // width, height
        NULL,                               // handle to parent
        NULL,                               // handle to menu
        hInstance,                          // application instance
        NULL);                              // no extra params

    hDC = GetDC(hwnd);

    // check if window creation failed (hwnd would equal NULL)
    if (!hwnd)
        return 0;

    ShowWindow(hwnd, SW_SHOW);          // display the window
    UpdateWindow(hwnd);                 // update the window


    while (!exiting)

        while (PeekMessage (&msg, NULL, 0, 0, PM_NOREMOVE))
            if (!GetMessage (&msg, NULL, 0, 0))
                exiting = true;

            TranslateMessage (&msg);
            DispatchMessage (&msg);

    delete g_glRender;

    if (fullscreen)
        ChangeDisplaySettings(NULL,0);          // If So Switch Back To The Desktop
        ShowCursor(TRUE);                       // Show Mouse Pointer

    return (int)msg.wParam;

cheers, lone [Edited by - Lonefox1 on June 3, 2005 7:38:42 AM]

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well...youre calling CreateWindowEx not sure how it handles the params as Ive never used it...but if you eliminate the Ex....such as this:

hwnd = CreateWindow(NULL, // extended style
"GLClass", // class name
"BOGLGP - Chapter 2 - OpenGL Application", // app name
0, 0, // x,y coordinate
windowRect.right - windowRect.left,
windowRect.bottom -, // width, height
NULL, // handle to parent
NULL, // handle to menu
hInstance, // application instance
NULL); // no extra params

it should fix your problem...

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