a window understanding

This is a discussion on a window understanding within the Windows Programming forums, part of the Platform Specific Boards category; i m learning windows api still starter in it went on some tutrial i understand almost all code but there ...

  1. #1
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    Dec 2008
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    183

    a window understanding

    i m learning windows api still starter in it went on some tutrial i understand almost all code but there is that line whish i don't understand
    const char g_szClassName[] = "Program";

    he says its class etc but i dont understand what it class of it its name doesnt even appear on task manager pls help me understand it more thanks anyways here is full code
    Code:
    #include <windows.h>
    
    const char g_szClassName[] = "myWindowClass";
    
    // Step 4: the Window Procedure
    LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
    {
        switch(msg)
        {
            case WM_CLOSE:
                DestroyWindow(hwnd);
            break;
            case WM_DESTROY:
                PostQuitMessage(0);
            break;
            default:
                return DefWindowProc(hwnd, msg, wParam, lParam);
        }
        return 0;
    }
    
    int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
        LPSTR lpCmdLine, int nCmdShow)
    {
        WNDCLASSEX wc;
        HWND hwnd;
        MSG Msg;
    
        //Step 1: Registering the Window Class
        wc.cbSize        = sizeof(WNDCLASSEX);
        wc.style         = 0;
        wc.lpfnWndProc   = WndProc;
        wc.cbClsExtra    = 0;
        wc.cbWndExtra    = 0;
        wc.hInstance     = hInstance;
        wc.hIcon         = LoadIcon(NULL, IDI_APPLICATION);
        wc.hCursor       = LoadCursor(NULL, IDC_ARROW);
        wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
        wc.lpszMenuName  = NULL;
        wc.lpszClassName = g_szClassName;
        wc.hIconSm       = LoadIcon(NULL, IDI_APPLICATION);
    
        if(!RegisterClassEx(&wc))
        {
            MessageBox(NULL, "Window Registration Failed!", "Error!",
                MB_ICONEXCLAMATION | MB_OK);
            return 0;
        }
    
        // Step 2: Creating the Window
        hwnd = CreateWindowEx(
            WS_EX_CLIENTEDGE,
            g_szClassName,
            "The title of my window",
            WS_OVERLAPPEDWINDOW,
            CW_USEDEFAULT, CW_USEDEFAULT, 240, 120,
            NULL, NULL, hInstance, NULL);
    
        if(hwnd == NULL)
        {
            MessageBox(NULL, "Window Creation Failed!", "Error!",
                MB_ICONEXCLAMATION | MB_OK);
            return 0;
        }
    
        ShowWindow(hwnd, nCmdShow);
        UpdateWindow(hwnd);
    
        // Step 3: The Message Loop
        while(GetMessage(&Msg, NULL, 0, 0) > 0)
        {
            TranslateMessage(&Msg);
            DispatchMessage(&Msg);
        }
        return Msg.wParam;
    }

  2. #2
    Ugly C Lover audinue's Avatar
    Join Date
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    Location
    Indonesia
    Posts
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    All windows based on a class identifier defined by the application by calling:
    Code:
    CreateWindowsEx(exStyle, className, ...);
    For instance if you want to create a button then set the className to BUTTON.
    Look at PSDK for more className information.

    However if you need a custom window, with custom window handler (WndProc listener), custom background, custom cursor, etc ... that exists in WNDCLASSEX struct then you must register the WNDCLASSEX with unique className identifier by using
    Code:
    RegisterClassEx(&wc);
    Somehow, look at your code:

    Code:
        switch(msg)
        {
            case WM_CLOSE:
                DestroyWindow(hwnd);
            break;
            case WM_DESTROY:
                PostQuitMessage(0);
            break;
            default:
                return DefWindowProc(hwnd, msg, wParam, lParam);
        }
        return 0; //DEAD statement, this statement will never be executed.
    Hope this will help.
    Last edited by audinue; 03-01-2009 at 10:12 PM.
    Just GET it OFF out my mind!!

  3. #3
    Registered User
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    Dec 2008
    Posts
    183
    yah thanks i also used spy++ in msv6 to understand more abt classes

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