newbie Windows problem...

This is a discussion on newbie Windows problem... within the Windows Programming forums, part of the Platform Specific Boards category; Code: #include <windows.h> int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd) { WNDCLASS wndclass; HWND hWindow; if(RegisterClass(&wndclass) == ...

  1. #1
    Rad gcn_zelda's Avatar
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    newbie Windows problem...

    Code:
    #include <windows.h>
    int WINAPI WinMain(HINSTANCE hInstance,
                       HINSTANCE hPrevInstance,
                       LPSTR lpCmdLine,
                       int nShowCmd)
    {
                       WNDCLASS wndclass;
                       HWND     hWindow;
                       if(RegisterClass(&wndclass) == 0)
                                                   return FALSE;
                       hWindow = CreateWindow
                       ("MyWindow",            // from wndclass.lpszClassName
                       "Gcn_Zelda's Window",        // this will show on title bar
                        WS_OVERLAPPEDWINDOW,   // border, title, min-max-close button
                        // WS_OVERLAPPED          // border, title
                        // WS_POPUP               // no title, no button
                        // WS_VISIBLE             // window is visible from start
                        // WS_VSCROLL             // window has vertical scroll bar
                        // WS_HSCROLL             // window has horizontal scroll bar
                        // WS_MAXIMIZE            // window is created in maximized state
                        // WS_MINIMIZE            // window is created in minimized state
                        0,                     // starting x-coord (upper-left)
                        0,                     // starting y-coord (upper-left)
                        CW_USEDEFAULT,         // window's x-size
                        CW_USEDEFAULT,         // window's y-size
                        NULL,                  // parent window's handle
                        NULL,                  // handle to a menu
                        hInstance,             // copy from WinMain()
                        NULL);                 // disregard...
                        if(hWindow == NULL)
                                return FALSE;
                        ShowWindow(hWindow, SW_SHOW);        // show created window
                                         // SW_HIDE          // hide created window
                                         // SW_RESTORE       // show window in restored state
                                         // SW_MAXIMIZE      // show window in maximized state
                                         // SW_MINIMIZE      // show window in minimized state
    }
    My program compiles, but the Console screen pops up and dissapears quickly. Does anybody know the problem? I'm using Dev C++ 4....

  2. #2
    C++ Developer XSquared's Avatar
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    Create a windows project, not a console project.
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  3. #3
    Rad gcn_zelda's Avatar
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    ...stupid me...thanks.

  4. #4
    Rad gcn_zelda's Avatar
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    I tried

    I just tried that and it still doesn't work. Now, the Dev-C++ screen minimizes and nothing happens. It says "Compilation Completed"

  5. #5
    carry on JaWiB's Avatar
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    not sure what your problem is, but you might want to do more if an error occurs, like:
    Code:
    if(hWindow == NULL)
    {
    MessageBox(NULL, "Window Creation Failed!", "Error!",
                MB_ICONEXCLAMATION | MB_OK);                            
    return FALSE ; //now return error
    }
    oh, and don't you have to do more to register the window? i haven't done windows programming in a while...
    "Think not but that I know these things; or think
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    Of knowing what I ought."
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  6. #6
    It's full of stars adrianxw's Avatar
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    >>> don't you have to do more to register the window?

    Not to actually register the class, but you'll certainly want to fill in the members of your wndclass structure, here is an example from one of my tutorial programs...

    Code:
        WinClass.cbSize = sizeof(WNDCLASSEX);   
        WinClass.hInstance = hThisInst;
        WinClass.lpszClassName = "Window";
        WinClass.lpfnWndProc = WindowFunc; 
        WinClass.style = 0;     
        WinClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
        WinClass.hIconSm = LoadIcon(NULL, IDI_WINLOGO);
        WinClass.hCursor = LoadCursor(NULL, IDC_ARROW);
        WinClass.lpszMenuName = NULL; 
        WinClass.cbClsExtra = 0; 
        WinClass.cbWndExtra = 0;
        WinClass.hbrBackground = (HBRUSH) GetStockObject(WHITE_BRUSH);
    ... change the structure name and any of the other things you want, NOTE I am using WNDCLASSEX, not WNDCLASS.
    Wave upon wave of demented avengers march cheerfully out of obscurity unto the dream.

  7. #7
    i want wookie cookies the Wookie's Avatar
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    isn't a callback function also required to handle the painting of the window? or will windows automatically handle that?

  8. #8
    Banned master5001's Avatar
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    Actually, you are missing someting crucial here. After registering you need to setup the callback system for your program:

    Example
    Code:
      MSG messages;
    
      while(GetMessage(&messages, NULL, 0, 0)) {
         TranslateMessage(&messages);
         DispatchMessage(&messages);
      }

  9. #9
    Cat
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    Yes, you are missing several important points:

    * You need to fill in some of the data members before you register the class. For example, you aren't supplying a class name or a callback function, so the class is useless (and you're making a window for a class that doesn't exist because you registered a class with an unknown name (an uninitialized name), but try to make a window of class "MyWindow"

    * You need a message pump (as master5001 said)

    * You need a window procedure (callback) that, at a minimum, responds to WM_DESTROY by calling PostQuitMessage(), and that passes all other calls to the default window procedure. This procedure is another function that you must specify in the class structure.

  10. #10
    It's full of stars adrianxw's Avatar
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    I had assumed that what you had posted was an extract. If that is, indeed, your whole program, then as the others have added, you are way off. Attached is a real basic Windows program.
    Attached Files Attached Files
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