Sending windows messages

This is a discussion on Sending windows messages within the Windows Programming forums, part of the Platform Specific Boards category; I made this windows source code (With Dev-C++) Code: #include <windows.h> #include <iostream> #include "resource.h" /* Declare Windows procedure */ ...

  1. #1
    C / C++
    Join Date
    Jan 2006
    Location
    The Netherlands
    Posts
    312

    Sending windows messages

    I made this windows source code (With Dev-C++)

    Code:
    #include <windows.h>
    #include <iostream>
    #include "resource.h"
    
    /*  Declare Windows procedure  */
    LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);
    
    /*  Make the class name into a global variable  */
    char szClassName[ ] = "Echt venster";
    
    int WINAPI WinMain (HINSTANCE hThisInstance,
                        HINSTANCE hPrevInstance,
                        LPSTR lpszArgument,
                        int nFunsterStil)
    
    {
        HWND hwnd;               /* This is the handle for our window */
        MSG messages;            /* Here messages to the application are saved */
        WNDCLASSEX wincl;        /* Data structure for the windowclass */
    
        /* The Window structure */
        wincl.hInstance = hThisInstance;
        wincl.lpszClassName = szClassName;
        wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
        wincl.style = CS_DBLCLKS;                 /* Catch double-clicks */
        wincl.cbSize = sizeof (WNDCLASSEX);
    
        /* Use default icon and mouse-pointer */
        wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
        wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
        wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
        wincl.lpszMenuName = NULL;                 /* No menu */
        wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
        wincl.cbWndExtra = 0;                      /* structure or the window instance */
        /* Use Windows's default color as the background of the window */
        wincl.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    
        
    
        /* Register the window class, and if it fails quit the program */
        if (!RegisterClassEx (&wincl))
            return 0;
    
        /* The class is registered, let's create the program*/
        hwnd = CreateWindowEx (
               0,                   /* Extended possibilites for variation */
               szClassName,         /* Classname */
               "Echt venster",       /* Title Text */
               WS_OVERLAPPEDWINDOW, /* default window */
               CW_USEDEFAULT,       /* Windows decides the position */
               CW_USEDEFAULT,       /* where the window ends up on the screen */
               544,                 /* The programs width */
               375,                 /* and height in pixels */
               HWND_DESKTOP,        /* The window is a child-window to desktop */
               NULL,                /* No menu */
               hThisInstance,       /* Program Instance handler */
               NULL                 /* No Window Creation data */
               );
    
        /* Make the window visible on the screen */
        ShowWindow (hwnd, nFunsterStil);
    
        int num = 5;
        
        if(num == 5)
        {
          messages = WM_DESTROY;
        }
    
        /* Run the message loop. It will run until GetMessage() returns 0 */
        while (GetMessage (&messages, NULL, 0, 0))
        {
            /* Translate virtual-key messages into character messages */
            TranslateMessage(&messages);
            /* Send message to WindowProcedure */
            DispatchMessage(&messages);
        }
    
        /* The program return-value is 0 - The value that PostQuitMessage() gave */
        return messages.wParam;
    }
    
    
    /*  This function is called by the Windows function DispatchMessage()  */
    
    LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
    {
        HDC         hdc;	//device context
        PAINTSTRUCT ps;	//paint stucture
        RECT        rect;     //rectangle sturcture
        switch (message)                  /* handle the messages */
        {
            case WM_DESTROY:
                PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
                break;
            case WM_PAINT:
                hdc = BeginPaint (hwnd, &ps) ;
              
                GetClientRect (hwnd, &rect) ;
              
                DrawText (hdc, TEXT ("hello world!"), -1, &rect,
                          DT_SINGLELINE | DT_LEFT | DT_TOP) ;
                EndPaint (hwnd, &ps) ;
                break;
            default:                      /* for messages that we don't deal with */
                return DefWindowProc (hwnd, message, wParam, lParam);
        }
    
        return 0;
    }
    Int this part:
    Code:
        int num = 5;
        
        if(num == 5)
        {
          messages = WM_DESTROY;
        }
    I want to send the message destroy but it sais:

    main.cpp: In function `int WinMain(HINSTANCE__*, HINSTANCE__*, CHAR*, int)':
    main.cpp:67: no match for `MSG& = int' operator
    C:/Dev-Cpp/include/winuser.h:2141: candidates are: tagMSG&
    tagMSG:perator=(const tagMSG&)
    How can I send a quit message to the "windows code"?
    Operating Systems:
    - Ubuntu 9.04
    - XP

    Compiler: gcc

  2. #2
    Confused Magos's Avatar
    Join Date
    Sep 2001
    Location
    Sweden
    Posts
    3,145
    Are you asking how to quit the message loop? call PostQuitMessage(0); or DestroyWindow(hwnd) as its WM_DESTROY handler calls PostQuitMessage (in your code above).
    MagosX.com

    Give a man a fish and you feed him for a day.
    Teach a man to fish and you feed him for a lifetime.

  3. #3
    C / C++
    Join Date
    Jan 2006
    Location
    The Netherlands
    Posts
    312
    And how can I call a second paint function?
    (Example: I want "Hello World" painted right and left in the window)
    Operating Systems:
    - Ubuntu 9.04
    - XP

    Compiler: gcc

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